merge: add options to warn or ignore on colliding unknown files

A 'colliding unknown file' is a file that meets all of the following
conditions:

- is untracked or ignored on disk
- is present in the changeset being merged or updated to
- has different contents

Previously, we would always abort whenever we saw such files. With this config
option we can choose to warn and back the unknown files up instead, or even
forgo the warning entirely and silently back the unknown files up.

Common use cases for this configuration include a large scale transition of
formerly ignored unknown files to tracked files. In some cases the files can be
given new names, but in other cases, external "convention over configuration"
constraints have determined that the file must retain the same name as before.

mercurial/help/config.txt

@@ -1,1935 +1,1948 b''
 The Mercurial system uses a set of configuration files to control
 aspects of its behavior.
 
 Troubleshooting
 ===============
 
 If you're having problems with your configuration,
 :hg:`config --debug` can help you understand what is introducing
 a setting into your environment.
 
 See :hg:`help config.syntax` and :hg:`help config.files`
 for information about how and where to override things.
 
 Structure
 =========
 
 The configuration files use a simple ini-file format. A configuration
 file consists of sections, led by a ``[section]`` header and followed
 by ``name = value`` entries::
 
   [ui]
   username = Firstname Lastname <[e-mail]>
   verbose = True
 
 The above entries will be referred to as ``ui.username`` and
 ``ui.verbose``, respectively. See :hg:`help config.syntax`.
 
 Files
 =====
 
 Mercurial reads configuration data from several files, if they exist.
 These files do not exist by default and you will have to create the
 appropriate configuration files yourself: global configuration like
 the username setting is typically put into
 ``%USERPROFILE%\mercurial.ini`` or ``$HOME/.hgrc`` and local
 configuration is put into the per-repository ``<repo>/.hg/hgrc`` file.
 
 The names of these files depend on the system on which Mercurial is
 installed. ``*.rc`` files from a single directory are read in
 alphabetical order, later ones overriding earlier ones. Where multiple
 paths are given below, settings from earlier paths override later
 ones.
 
 .. container:: verbose.unix
 
   On Unix, the following files are consulted:
 
   - ``<repo>/.hg/hgrc`` (per-repository)
   - ``$HOME/.hgrc`` (per-user)
   - ``<install-root>/etc/mercurial/hgrc`` (per-installation)
   - ``<install-root>/etc/mercurial/hgrc.d/*.rc`` (per-installation)
   - ``/etc/mercurial/hgrc`` (per-system)
   - ``/etc/mercurial/hgrc.d/*.rc`` (per-system)
   - ``<internal>/default.d/*.rc`` (defaults)
 
 .. container:: verbose.windows
 
   On Windows, the following files are consulted:
 
   - ``<repo>/.hg/hgrc`` (per-repository)
   - ``%USERPROFILE%\.hgrc`` (per-user)
   - ``%USERPROFILE%\Mercurial.ini`` (per-user)
   - ``%HOME%\.hgrc`` (per-user)
   - ``%HOME%\Mercurial.ini`` (per-user)
   - ``HKEY_LOCAL_MACHINE\SOFTWARE\Mercurial`` (per-installation)
   - ``<install-dir>\hgrc.d\*.rc`` (per-installation)
   - ``<install-dir>\Mercurial.ini`` (per-installation)
   - ``<internal>/default.d/*.rc`` (defaults)
 
   .. note::
 
    The registry key ``HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mercurial``
    is used when running 32-bit Python on 64-bit Windows.
 
 .. container:: verbose.plan9
 
   On Plan9, the following files are consulted:
 
   - ``<repo>/.hg/hgrc`` (per-repository)
   - ``$home/lib/hgrc`` (per-user)
   - ``<install-root>/lib/mercurial/hgrc`` (per-installation)
   - ``<install-root>/lib/mercurial/hgrc.d/*.rc`` (per-installation)
   - ``/lib/mercurial/hgrc`` (per-system)
   - ``/lib/mercurial/hgrc.d/*.rc`` (per-system)
   - ``<internal>/default.d/*.rc`` (defaults)
 
 Per-repository configuration options only apply in a
 particular repository. This file is not version-controlled, and
 will not get transferred during a "clone" operation. Options in
 this file override options in all other configuration files. On
 Plan 9 and Unix, most of this file will be ignored if it doesn't
 belong to a trusted user or to a trusted group. See
 :hg:`help config.trusted` for more details.
 
 Per-user configuration file(s) are for the user running Mercurial. On
 Windows 9x, ``%HOME%`` is replaced by ``%APPDATA%``. Options in these
 files apply to all Mercurial commands executed by this user in any
 directory. Options in these files override per-system and per-installation
 options.
 
 Per-installation configuration files are searched for in the
 directory where Mercurial is installed. ``<install-root>`` is the
 parent directory of the **hg** executable (or symlink) being run. For
 example, if installed in ``/shared/tools/bin/hg``, Mercurial will look
 in ``/shared/tools/etc/mercurial/hgrc``. Options in these files apply
 to all Mercurial commands executed by any user in any directory.
 
 Per-installation configuration files are for the system on
 which Mercurial is running. Options in these files apply to all
 Mercurial commands executed by any user in any directory. Registry
 keys contain PATH-like strings, every part of which must reference
 a ``Mercurial.ini`` file or be a directory where ``*.rc`` files will
 be read.  Mercurial checks each of these locations in the specified
 order until one or more configuration files are detected.
 
 Per-system configuration files are for the system on which Mercurial
 is running. Options in these files apply to all Mercurial commands
 executed by any user in any directory. Options in these files
 override per-installation options.
 
 Mercurial comes with some default configuration. The default configuration
 files are installed with Mercurial and will be overwritten on upgrades. Default
 configuration files should never be edited by users or administrators but can
 be overridden in other configuration files. So far the directory only contains
 merge tool configuration but packagers can also put other default configuration
 there.
 
 Syntax
 ======
 
 A configuration file consists of sections, led by a ``[section]`` header
 and followed by ``name = value`` entries (sometimes called
 ``configuration keys``)::
 
     [spam]
     eggs=ham
     green=
        eggs
 
 Each line contains one entry. If the lines that follow are indented,
 they are treated as continuations of that entry. Leading whitespace is
 removed from values. Empty lines are skipped. Lines beginning with
 ``#`` or ``;`` are ignored and may be used to provide comments.
 
 Configuration keys can be set multiple times, in which case Mercurial
 will use the value that was configured last. As an example::
 
     [spam]
     eggs=large
     ham=serrano
     eggs=small
 
 This would set the configuration key named ``eggs`` to ``small``.
 
 It is also possible to define a section multiple times. A section can
 be redefined on the same and/or on different configuration files. For
 example::
 
     [foo]
     eggs=large
     ham=serrano
     eggs=small
 
     [bar]
     eggs=ham
     green=
        eggs
 
     [foo]
     ham=prosciutto
     eggs=medium
     bread=toasted
 
 This would set the ``eggs``, ``ham``, and ``bread`` configuration keys
 of the ``foo`` section to ``medium``, ``prosciutto``, and ``toasted``,
 respectively. As you can see there only thing that matters is the last
 value that was set for each of the configuration keys.
 
 If a configuration key is set multiple times in different
 configuration files the final value will depend on the order in which
 the different configuration files are read, with settings from earlier
 paths overriding later ones as described on the ``Files`` section
 above.
 
 A line of the form ``%include file`` will include ``file`` into the
 current configuration file. The inclusion is recursive, which means
 that included files can include other files. Filenames are relative to
 the configuration file in which the ``%include`` directive is found.
 Environment variables and ``~user`` constructs are expanded in
 ``file``. This lets you do something like::
 
   %include ~/.hgrc.d/$HOST.rc
 
 to include a different configuration file on each computer you use.
 
 A line with ``%unset name`` will remove ``name`` from the current
 section, if it has been set previously.
 
 The values are either free-form text strings, lists of text strings,
 or Boolean values. Boolean values can be set to true using any of "1",
 "yes", "true", or "on" and to false using "0", "no", "false", or "off"
 (all case insensitive).
 
 List values are separated by whitespace or comma, except when values are
 placed in double quotation marks::
 
   allow_read = "John Doe, PhD", brian, betty
 
 Quotation marks can be escaped by prefixing them with a backslash. Only
 quotation marks at the beginning of a word is counted as a quotation
 (e.g., ``foo"bar baz`` is the list of ``foo"bar`` and ``baz``).
 
 Sections
 ========
 
 This section describes the different sections that may appear in a
 Mercurial configuration file, the purpose of each section, its possible
 keys, and their possible values.
 
 ``alias``
 ---------
 
 Defines command aliases.
 
 Aliases allow you to define your own commands in terms of other
 commands (or aliases), optionally including arguments. Positional
 arguments in the form of ``$1``, ``$2``, etc. in the alias definition
 are expanded by Mercurial before execution. Positional arguments not
 already used by ``$N`` in the definition are put at the end of the
 command to be executed.
 
 Alias definitions consist of lines of the form::
 
     <alias> = <command> [<argument>]...
 
 For example, this definition::
 
     latest = log --limit 5
 
 creates a new command ``latest`` that shows only the five most recent
 changesets. You can define subsequent aliases using earlier ones::
 
     stable5 = latest -b stable
 
 .. note::
 
    It is possible to create aliases with the same names as
    existing commands, which will then override the original
    definitions. This is almost always a bad idea!
 
 An alias can start with an exclamation point (``!``) to make it a
 shell alias. A shell alias is executed with the shell and will let you
 run arbitrary commands. As an example, ::
 
    echo = !echo $@
 
 will let you do ``hg echo foo`` to have ``foo`` printed in your
 terminal. A better example might be::
 
    purge = !$HG status --no-status --unknown -0 | xargs -0 rm
 
 which will make ``hg purge`` delete all unknown files in the
 repository in the same manner as the purge extension.
 
 Positional arguments like ``$1``, ``$2``, etc. in the alias definition
 expand to the command arguments. Unmatched arguments are
 removed. ``$0`` expands to the alias name and ``$@`` expands to all
 arguments separated by a space. ``"$@"`` (with quotes) expands to all
 arguments quoted individually and separated by a space. These expansions
 happen before the command is passed to the shell.
 
 Shell aliases are executed in an environment where ``$HG`` expands to
 the path of the Mercurial that was used to execute the alias. This is
 useful when you want to call further Mercurial commands in a shell
 alias, as was done above for the purge alias. In addition,
 ``$HG_ARGS`` expands to the arguments given to Mercurial. In the ``hg
 echo foo`` call above, ``$HG_ARGS`` would expand to ``echo foo``.
 
 .. note::
 
    Some global configuration options such as ``-R`` are
    processed before shell aliases and will thus not be passed to
    aliases.
 
 
 ``annotate``
 ------------
 
 Settings used when displaying file annotations. All values are
 Booleans and default to False. See :hg:`help config.diff` for
 related options for the diff command.
 
 ``ignorews``
     Ignore white space when comparing lines.
 
 ``ignorewsamount``
     Ignore changes in the amount of white space.
 
 ``ignoreblanklines``
     Ignore changes whose lines are all blank.
 
 
 ``auth``
 --------
 
 Authentication credentials for HTTP authentication. This section
 allows you to store usernames and passwords for use when logging
 *into* HTTP servers. See :hg:`help config.web` if
 you want to configure *who* can login to your HTTP server.
 
 Each line has the following format::
 
     <name>.<argument> = <value>
 
 where ``<name>`` is used to group arguments into authentication
 entries. Example::
 
     foo.prefix = hg.intevation.org/mercurial
     foo.username = foo
     foo.password = bar
     foo.schemes = http https
 
     bar.prefix = secure.example.org
     bar.key = path/to/file.key
     bar.cert = path/to/file.cert
     bar.schemes = https
 
 Supported arguments:
 
 ``prefix``
     Either ``*`` or a URI prefix with or without the scheme part.
     The authentication entry with the longest matching prefix is used
     (where ``*`` matches everything and counts as a match of length
     1). If the prefix doesn't include a scheme, the match is performed
     against the URI with its scheme stripped as well, and the schemes
     argument, q.v., is then subsequently consulted.
 
 ``username``
     Optional. Username to authenticate with. If not given, and the
     remote site requires basic or digest authentication, the user will
     be prompted for it. Environment variables are expanded in the
     username letting you do ``foo.username = $USER``. If the URI
     includes a username, only ``[auth]`` entries with a matching
     username or without a username will be considered.
 
 ``password``
     Optional. Password to authenticate with. If not given, and the
     remote site requires basic or digest authentication, the user
     will be prompted for it.
 
 ``key``
     Optional. PEM encoded client certificate key file. Environment
     variables are expanded in the filename.
 
 ``cert``
     Optional. PEM encoded client certificate chain file. Environment
     variables are expanded in the filename.
 
 ``schemes``
     Optional. Space separated list of URI schemes to use this
     authentication entry with. Only used if the prefix doesn't include
     a scheme. Supported schemes are http and https. They will match
     static-http and static-https respectively, as well.
     (default: https)
 
 If no suitable authentication entry is found, the user is prompted
 for credentials as usual if required by the remote.
 
 
 ``committemplate``
 ------------------
 
 ``changeset``
     String: configuration in this section is used as the template to
     customize the text shown in the editor when committing.
 
 In addition to pre-defined template keywords, commit log specific one
 below can be used for customization:
 
 ``extramsg``
     String: Extra message (typically 'Leave message empty to abort
     commit.'). This may be changed by some commands or extensions.
 
 For example, the template configuration below shows as same text as
 one shown by default::
 
     [committemplate]
     changeset = {desc}\n\n
         HG: Enter commit message.  Lines beginning with 'HG:' are removed.
         HG: {extramsg}
         HG: --
         HG: user: {author}\n{ifeq(p2rev, "-1", "",
        "HG: branch merge\n")
        }HG: branch '{branch}'\n{if(activebookmark,
        "HG: bookmark '{activebookmark}'\n")   }{subrepos %
        "HG: subrepo {subrepo}\n"              }{file_adds %
        "HG: added {file}\n"                   }{file_mods %
        "HG: changed {file}\n"                 }{file_dels %
        "HG: removed {file}\n"                 }{if(files, "",
        "HG: no files changed\n")}
 
 .. note::
 
    For some problematic encodings (see :hg:`help win32mbcs` for
    detail), this customization should be configured carefully, to
    avoid showing broken characters.
 
    For example, if a multibyte character ending with backslash (0x5c) is
    followed by the ASCII character 'n' in the customized template,
    the sequence of backslash and 'n' is treated as line-feed unexpectedly
    (and the multibyte character is broken, too).
 
 Customized template is used for commands below (``--edit`` may be
 required):
 
 - :hg:`backout`
 - :hg:`commit`
 - :hg:`fetch` (for merge commit only)
 - :hg:`graft`
 - :hg:`histedit`
 - :hg:`import`
 - :hg:`qfold`, :hg:`qnew` and :hg:`qrefresh`
 - :hg:`rebase`
 - :hg:`shelve`
 - :hg:`sign`
 - :hg:`tag`
 - :hg:`transplant`
 
 Configuring items below instead of ``changeset`` allows showing
 customized message only for specific actions, or showing different
 messages for each action.
 
 - ``changeset.backout`` for :hg:`backout`
 - ``changeset.commit.amend.merge`` for :hg:`commit --amend` on merges
 - ``changeset.commit.amend.normal`` for :hg:`commit --amend` on other
 - ``changeset.commit.normal.merge`` for :hg:`commit` on merges
 - ``changeset.commit.normal.normal`` for :hg:`commit` on other
 - ``changeset.fetch`` for :hg:`fetch` (impling merge commit)
 - ``changeset.gpg.sign`` for :hg:`sign`
 - ``changeset.graft`` for :hg:`graft`
 - ``changeset.histedit.edit`` for ``edit`` of :hg:`histedit`
 - ``changeset.histedit.fold`` for ``fold`` of :hg:`histedit`
 - ``changeset.histedit.mess`` for ``mess`` of :hg:`histedit`
 - ``changeset.histedit.pick`` for ``pick`` of :hg:`histedit`
 - ``changeset.import.bypass`` for :hg:`import --bypass`
 - ``changeset.import.normal.merge`` for :hg:`import` on merges
 - ``changeset.import.normal.normal`` for :hg:`import` on other
 - ``changeset.mq.qnew`` for :hg:`qnew`
 - ``changeset.mq.qfold`` for :hg:`qfold`
 - ``changeset.mq.qrefresh`` for :hg:`qrefresh`
 - ``changeset.rebase.collapse`` for :hg:`rebase --collapse`
 - ``changeset.rebase.merge`` for :hg:`rebase` on merges
 - ``changeset.rebase.normal`` for :hg:`rebase` on other
 - ``changeset.shelve.shelve`` for :hg:`shelve`
 - ``changeset.tag.add`` for :hg:`tag` without ``--remove``
 - ``changeset.tag.remove`` for :hg:`tag --remove`
 - ``changeset.transplant.merge`` for :hg:`transplant` on merges
 - ``changeset.transplant.normal`` for :hg:`transplant` on other
 
 These dot-separated lists of names are treated as hierarchical ones.
 For example, ``changeset.tag.remove`` customizes the commit message
 only for :hg:`tag --remove`, but ``changeset.tag`` customizes the
 commit message for :hg:`tag` regardless of ``--remove`` option.
 
 When the external editor is invoked for a commit, the corresponding
 dot-separated list of names without the ``changeset.`` prefix
 (e.g. ``commit.normal.normal``) is in the ``HGEDITFORM`` environment
 variable.
 
 In this section, items other than ``changeset`` can be referred from
 others. For example, the configuration to list committed files up
 below can be referred as ``{listupfiles}``::
 
     [committemplate]
     listupfiles = {file_adds %
        "HG: added {file}\n"     }{file_mods %
        "HG: changed {file}\n"   }{file_dels %
        "HG: removed {file}\n"   }{if(files, "",
        "HG: no files changed\n")}
 
 ``decode/encode``
 -----------------
 
 Filters for transforming files on checkout/checkin. This would
 typically be used for newline processing or other
 localization/canonicalization of files.
 
 Filters consist of a filter pattern followed by a filter command.
 Filter patterns are globs by default, rooted at the repository root.
 For example, to match any file ending in ``.txt`` in the root
 directory only, use the pattern ``*.txt``. To match any file ending
 in ``.c`` anywhere in the repository, use the pattern ``**.c``.
 For each file only the first matching filter applies.
 
 The filter command can start with a specifier, either ``pipe:`` or
 ``tempfile:``. If no specifier is given, ``pipe:`` is used by default.
 
 A ``pipe:`` command must accept data on stdin and return the transformed
 data on stdout.
 
 Pipe example::
 
   [encode]
   # uncompress gzip files on checkin to improve delta compression
   # note: not necessarily a good idea, just an example
   *.gz = pipe: gunzip
 
   [decode]
   # recompress gzip files when writing them to the working dir (we
   # can safely omit "pipe:", because it's the default)
   *.gz = gzip
 
 A ``tempfile:`` command is a template. The string ``INFILE`` is replaced
 with the name of a temporary file that contains the data to be
 filtered by the command. The string ``OUTFILE`` is replaced with the name
 of an empty temporary file, where the filtered data must be written by
 the command.
 
 .. note::
 
    The tempfile mechanism is recommended for Windows systems,
    where the standard shell I/O redirection operators often have
    strange effects and may corrupt the contents of your files.
 
 This filter mechanism is used internally by the ``eol`` extension to
 translate line ending characters between Windows (CRLF) and Unix (LF)
 format. We suggest you use the ``eol`` extension for convenience.
 
 
 ``defaults``
 ------------
 
 (defaults are deprecated. Don't use them. Use aliases instead.)
 
 Use the ``[defaults]`` section to define command defaults, i.e. the
 default options/arguments to pass to the specified commands.
 
 The following example makes :hg:`log` run in verbose mode, and
 :hg:`status` show only the modified files, by default::
 
   [defaults]
   log = -v
   status = -m
 
 The actual commands, instead of their aliases, must be used when
 defining command defaults. The command defaults will also be applied
 to the aliases of the commands defined.
 
 
 ``diff``
 --------
 
 Settings used when displaying diffs. Everything except for ``unified``
 is a Boolean and defaults to False. See :hg:`help config.annotate`
 for related options for the annotate command.
 
 ``git``
     Use git extended diff format.
 
 ``nobinary``
     Omit git binary patches.
 
 ``nodates``
     Don't include dates in diff headers.
 
 ``noprefix``
     Omit 'a/' and 'b/' prefixes from filenames. Ignored in plain mode.
 
 ``showfunc``
     Show which function each change is in.
 
 ``ignorews``
     Ignore white space when comparing lines.
 
 ``ignorewsamount``
     Ignore changes in the amount of white space.
 
 ``ignoreblanklines``
     Ignore changes whose lines are all blank.
 
 ``unified``
     Number of lines of context to show.
 
 ``email``
 ---------
 
 Settings for extensions that send email messages.
 
 ``from``
     Optional. Email address to use in "From" header and SMTP envelope
     of outgoing messages.
 
 ``to``
     Optional. Comma-separated list of recipients' email addresses.
 
 ``cc``
     Optional. Comma-separated list of carbon copy recipients'
     email addresses.
 
 ``bcc``
     Optional. Comma-separated list of blind carbon copy recipients'
     email addresses.
 
 ``method``
     Optional. Method to use to send email messages. If value is ``smtp``
     (default), use SMTP (see the ``[smtp]`` section for configuration).
     Otherwise, use as name of program to run that acts like sendmail
     (takes ``-f`` option for sender, list of recipients on command line,
     message on stdin). Normally, setting this to ``sendmail`` or
     ``/usr/sbin/sendmail`` is enough to use sendmail to send messages.
 
 ``charsets``
     Optional. Comma-separated list of character sets considered
     convenient for recipients. Addresses, headers, and parts not
     containing patches of outgoing messages will be encoded in the
     first character set to which conversion from local encoding
     (``$HGENCODING``, ``ui.fallbackencoding``) succeeds. If correct
     conversion fails, the text in question is sent as is.
     (default: '')
 
     Order of outgoing email character sets:
 
     1. ``us-ascii``: always first, regardless of settings
     2. ``email.charsets``: in order given by user
     3. ``ui.fallbackencoding``: if not in email.charsets
     4. ``$HGENCODING``: if not in email.charsets
     5. ``utf-8``: always last, regardless of settings
 
 Email example::
 
   [email]
   from = Joseph User <[e-mail]>
   method = /usr/sbin/sendmail
   # charsets for western Europeans
   # us-ascii, utf-8 omitted, as they are tried first and last
   charsets = iso-8859-1, iso-8859-15, windows-1252
 
 
 ``extensions``
 --------------
 
 Mercurial has an extension mechanism for adding new features. To
 enable an extension, create an entry for it in this section.
 
 If you know that the extension is already in Python's search path,
 you can give the name of the module, followed by ``=``, with nothing
 after the ``=``.
 
 Otherwise, give a name that you choose, followed by ``=``, followed by
 the path to the ``.py`` file (including the file name extension) that
 defines the extension.
 
 To explicitly disable an extension that is enabled in an hgrc of
 broader scope, prepend its path with ``!``, as in ``foo = !/ext/path``
 or ``foo = !`` when path is not supplied.
 
 Example for ``~/.hgrc``::
 
   [extensions]
   # (the color extension will get loaded from Mercurial's path)
   color =
   # (this extension will get loaded from the file specified)
   myfeature = ~/.hgext/myfeature.py
 
 
 ``format``
 ----------
 
 ``usegeneraldelta``
     Enable or disable the "generaldelta" repository format which improves
     repository compression by allowing "revlog" to store delta against arbitrary
     revision instead of the previous stored one. This provides significant
     improvement for repositories with branches.
 
     Repositories with this on-disk format require Mercurial version 1.9.
 
     Enabled by default.
 
 ``dotencode``
     Enable or disable the "dotencode" repository format which enhances
     the "fncache" repository format (which has to be enabled to use
     dotencode) to avoid issues with filenames starting with ._ on
     Mac OS X and spaces on Windows.
 
     Repositories with this on-disk format require Mercurial version 1.7.
 
     Enabled by default.
 
 ``usefncache``
     Enable or disable the "fncache" repository format which enhances
     the "store" repository format (which has to be enabled to use
     fncache) to allow longer filenames and avoids using Windows
     reserved names, e.g. "nul".
 
     Repositories with this on-disk format require Mercurial version 1.1.
 
     Enabled by default.
 
 ``usestore``
     Enable or disable the "store" repository format which improves
     compatibility with systems that fold case or otherwise mangle
     filenames. Disabling this option will allow you to store longer filenames
     in some situations at the expense of compatibility.
 
     Repositories with this on-disk format require Mercurial version 0.9.4.
 
     Enabled by default.
 
 ``graph``
 ---------
 
 Web graph view configuration. This section let you change graph
 elements display properties by branches, for instance to make the
 ``default`` branch stand out.
 
 Each line has the following format::
 
     <branch>.<argument> = <value>
 
 where ``<branch>`` is the name of the branch being
 customized. Example::
 
     [graph]
     # 2px width
     default.width = 2
     # red color
     default.color = FF0000
 
 Supported arguments:
 
 ``width``
     Set branch edges width in pixels.
 
 ``color``
     Set branch edges color in hexadecimal RGB notation.
 
 ``hooks``
 ---------
 
 Commands or Python functions that get automatically executed by
 various actions such as starting or finishing a commit. Multiple
 hooks can be run for the same action by appending a suffix to the
 action. Overriding a site-wide hook can be done by changing its
 value or setting it to an empty string.  Hooks can be prioritized
 by adding a prefix of ``priority.`` to the hook name on a new line
 and setting the priority. The default priority is 0.
 
 Example ``.hg/hgrc``::
 
   [hooks]
   # update working directory after adding changesets
   changegroup.update = hg update
   # do not use the site-wide hook
   incoming =
   incoming.email = /my/email/hook
   incoming.autobuild = /my/build/hook
   # force autobuild hook to run before other incoming hooks
   priority.incoming.autobuild = 1
 
 Most hooks are run with environment variables set that give useful
 additional information. For each hook below, the environment
 variables it is passed are listed with names of the form ``$HG_foo``.
 
 ``changegroup``
   Run after a changegroup has been added via push, pull or unbundle.
   ID of the first new changeset is in ``$HG_NODE``. URL from which
   changes came is in ``$HG_URL``.
 
 ``commit``
   Run after a changeset has been created in the local repository. ID
   of the newly created changeset is in ``$HG_NODE``. Parent changeset
   IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.
 
 ``incoming``
   Run after a changeset has been pulled, pushed, or unbundled into
   the local repository. The ID of the newly arrived changeset is in
   ``$HG_NODE``. URL that was source of changes came is in ``$HG_URL``.
 
 ``outgoing``
   Run after sending changes from local repository to another. ID of
   first changeset sent is in ``$HG_NODE``. Source of operation is in
   ``$HG_SOURCE``; Also see :hg:`help config.preoutgoing` hook.
 
 ``post-<command>``
   Run after successful invocations of the associated command. The
   contents of the command line are passed as ``$HG_ARGS`` and the result
   code in ``$HG_RESULT``. Parsed command line arguments are passed as
   ``$HG_PATS`` and ``$HG_OPTS``. These contain string representations of
   the python data internally passed to <command>. ``$HG_OPTS`` is a
   dictionary of options (with unspecified options set to their defaults).
   ``$HG_PATS`` is a list of arguments. Hook failure is ignored.
 
 ``pre-<command>``
   Run before executing the associated command. The contents of the
   command line are passed as ``$HG_ARGS``. Parsed command line arguments
   are passed as ``$HG_PATS`` and ``$HG_OPTS``. These contain string
   representations of the data internally passed to <command>. ``$HG_OPTS``
   is a dictionary of options (with unspecified options set to their
   defaults). ``$HG_PATS`` is a list of arguments. If the hook returns
   failure, the command doesn't execute and Mercurial returns the failure
   code.
 
 ``prechangegroup``
   Run before a changegroup is added via push, pull or unbundle. Exit
   status 0 allows the changegroup to proceed. Non-zero status will
   cause the push, pull or unbundle to fail. URL from which changes
   will come is in ``$HG_URL``.
 
 ``precommit``
   Run before starting a local commit. Exit status 0 allows the
   commit to proceed. Non-zero status will cause the commit to fail.
   Parent changeset IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.
 
 ``prelistkeys``
   Run before listing pushkeys (like bookmarks) in the
   repository. Non-zero status will cause failure. The key namespace is
   in ``$HG_NAMESPACE``.
 
 ``preoutgoing``
   Run before collecting changes to send from the local repository to
   another. Non-zero status will cause failure. This lets you prevent
   pull over HTTP or SSH. Also prevents against local pull, push
   (outbound) or bundle commands, but not effective, since you can
   just copy files instead then. Source of operation is in
   ``$HG_SOURCE``. If "serve", operation is happening on behalf of remote
   SSH or HTTP repository. If "push", "pull" or "bundle", operation
   is happening on behalf of repository on same system.
 
 ``prepushkey``
   Run before a pushkey (like a bookmark) is added to the
   repository. Non-zero status will cause the key to be rejected. The
   key namespace is in ``$HG_NAMESPACE``, the key is in ``$HG_KEY``,
   the old value (if any) is in ``$HG_OLD``, and the new value is in
   ``$HG_NEW``.
 
 ``pretag``
   Run before creating a tag. Exit status 0 allows the tag to be
   created. Non-zero status will cause the tag to fail. ID of
   changeset to tag is in ``$HG_NODE``. Name of tag is in ``$HG_TAG``. Tag is
   local if ``$HG_LOCAL=1``, in repository if ``$HG_LOCAL=0``.
 
 ``pretxnopen``
   Run before any new repository transaction is open. The reason for the
   transaction will be in ``$HG_TXNNAME`` and a unique identifier for the
   transaction will be in ``HG_TXNID``. A non-zero status will prevent the
   transaction from being opened.
 
 ``pretxnclose``
   Run right before the transaction is actually finalized. Any
   repository change will be visible to the hook program. This lets you
   validate the transaction content or change it. Exit status 0 allows
   the commit to proceed. Non-zero status will cause the transaction to
   be rolled back. The reason for the transaction opening will be in
   ``$HG_TXNNAME`` and a unique identifier for the transaction will be in
   ``HG_TXNID``. The rest of the available data will vary according the
   transaction type. New changesets will add ``$HG_NODE`` (id of the
   first added changeset), ``$HG_URL`` and ``$HG_SOURCE`` variables,
   bookmarks and phases changes will set ``HG_BOOKMARK_MOVED`` and
   ``HG_PHASES_MOVED`` to ``1``, etc.
 
 ``txnclose``
   Run after any repository transaction has been committed. At this
   point, the transaction can no longer be rolled back. The hook will run
   after the lock is released. See :hg:`help config.pretxnclose` docs for
   details about available variables.
 
 ``txnabort``
   Run when a transaction is aborted. See :hg:`help config.pretxnclose`
   docs for details about available variables.
 
 ``pretxnchangegroup``
   Run after a changegroup has been added via push, pull or unbundle,
   but before the transaction has been committed. Changegroup is
   visible to hook program. This lets you validate incoming changes
   before accepting them. Passed the ID of the first new changeset in
   ``$HG_NODE``. Exit status 0 allows the transaction to commit. Non-zero
   status will cause the transaction to be rolled back and the push,
   pull or unbundle will fail. URL that was source of changes is in
   ``$HG_URL``.
 
 ``pretxncommit``
   Run after a changeset has been created but the transaction not yet
   committed. Changeset is visible to hook program. This lets you
   validate commit message and changes. Exit status 0 allows the
   commit to proceed. Non-zero status will cause the transaction to
   be rolled back. ID of changeset is in ``$HG_NODE``. Parent changeset
   IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.
 
 ``preupdate``
   Run before updating the working directory. Exit status 0 allows
   the update to proceed. Non-zero status will prevent the update.
   Changeset ID of first new parent is in ``$HG_PARENT1``. If merge, ID
   of second new parent is in ``$HG_PARENT2``.
 
 ``listkeys``
   Run after listing pushkeys (like bookmarks) in the repository. The
   key namespace is in ``$HG_NAMESPACE``. ``$HG_VALUES`` is a
   dictionary containing the keys and values.
 
 ``pushkey``
   Run after a pushkey (like a bookmark) is added to the
   repository. The key namespace is in ``$HG_NAMESPACE``, the key is in
   ``$HG_KEY``, the old value (if any) is in ``$HG_OLD``, and the new
   value is in ``$HG_NEW``.
 
 ``tag``
   Run after a tag is created. ID of tagged changeset is in ``$HG_NODE``.
   Name of tag is in ``$HG_TAG``. Tag is local if ``$HG_LOCAL=1``, in
   repository if ``$HG_LOCAL=0``.
 
 ``update``
   Run after updating the working directory. Changeset ID of first
   new parent is in ``$HG_PARENT1``. If merge, ID of second new parent is
   in ``$HG_PARENT2``. If the update succeeded, ``$HG_ERROR=0``. If the
   update failed (e.g. because conflicts not resolved), ``$HG_ERROR=1``.
 
 .. note::
 
    It is generally better to use standard hooks rather than the
    generic pre- and post- command hooks as they are guaranteed to be
    called in the appropriate contexts for influencing transactions.
    Also, hooks like "commit" will be called in all contexts that
    generate a commit (e.g. tag) and not just the commit command.
 
 .. note::
 
    Environment variables with empty values may not be passed to
    hooks on platforms such as Windows. As an example, ``$HG_PARENT2``
    will have an empty value under Unix-like platforms for non-merge
    changesets, while it will not be available at all under Windows.
 
 The syntax for Python hooks is as follows::
 
   hookname = python:modulename.submodule.callable
   hookname = python:/path/to/python/module.py:callable
 
 Python hooks are run within the Mercurial process. Each hook is
 called with at least three keyword arguments: a ui object (keyword
 ``ui``), a repository object (keyword ``repo``), and a ``hooktype``
 keyword that tells what kind of hook is used. Arguments listed as
 environment variables above are passed as keyword arguments, with no
 ``HG_`` prefix, and names in lower case.
 
 If a Python hook returns a "true" value or raises an exception, this
 is treated as a failure.
 
 
 ``hostfingerprints``
 --------------------
 
 Fingerprints of the certificates of known HTTPS servers.
 A HTTPS connection to a server with a fingerprint configured here will
 only succeed if the servers certificate matches the fingerprint.
 This is very similar to how ssh known hosts works.
 The fingerprint is the SHA-1 hash value of the DER encoded certificate.
 The CA chain and web.cacerts is not used for servers with a fingerprint.
 
 For example::
 
     [hostfingerprints]
     hg.intevation.org = fa:1f:d9:48:f1:e7:74:30:38:8d:d8:58:b6:94:b8:58:28:7d:8b:d0
 
 This feature is only supported when using Python 2.6 or later.
 
 
 ``http_proxy``
 --------------
 
 Used to access web-based Mercurial repositories through a HTTP
 proxy.
 
 ``host``
     Host name and (optional) port of the proxy server, for example
     "myproxy:8000".
 
 ``no``
     Optional. Comma-separated list of host names that should bypass
     the proxy.
 
 ``passwd``
     Optional. Password to authenticate with at the proxy server.
 
 ``user``
     Optional. User name to authenticate with at the proxy server.
 
 ``always``
     Optional. Always use the proxy, even for localhost and any entries
     in ``http_proxy.no``. (default: False)
 
+``merge``
+---------
+
+This section specifies behavior during merges and updates.
+
+``checkunknown``
+   Controls behavior when an unknown file on disk has the same name as a tracked
+   file in the changeset being merged or updated to, and has different
+   contents. Options are ``abort``, ``warn`` and ``ignore``. With ``abort``,
+   abort on such files. With ``warn``, warn on such files and back them up as
+   .orig. With ``ignore``, don't print a warning and back them up as
+   .orig. (default: ``abort``)
+
 ``merge-patterns``
 ------------------
 
 This section specifies merge tools to associate with particular file
 patterns. Tools matched here will take precedence over the default
 merge tool. Patterns are globs by default, rooted at the repository
 root.
 
 Example::
 
   [merge-patterns]
   **.c = kdiff3
   **.jpg = myimgmerge
 
 ``merge-tools``
 ---------------
 
 This section configures external merge tools to use for file-level
 merges. This section has likely been preconfigured at install time.
 Use :hg:`config merge-tools` to check the existing configuration.
 Also see :hg:`help merge-tools` for more details.
 
 Example ``~/.hgrc``::
 
   [merge-tools]
   # Override stock tool location
   kdiff3.executable = ~/bin/kdiff3
   # Specify command line
   kdiff3.args = $base $local $other -o $output
   # Give higher priority
   kdiff3.priority = 1
 
   # Changing the priority of preconfigured tool
   meld.priority = 0
 
   # Disable a preconfigured tool
   vimdiff.disabled = yes
 
   # Define new tool
   myHtmlTool.args = -m $local $other $base $output
   myHtmlTool.regkey = Software\FooSoftware\HtmlMerge
   myHtmlTool.priority = 1
 
 Supported arguments:
 
 ``priority``
   The priority in which to evaluate this tool.
   (default: 0)
 
 ``executable``
   Either just the name of the executable or its pathname.  On Windows,
   the path can use environment variables with ${ProgramFiles} syntax.
   (default: the tool name)
 
 ``args``
   The arguments to pass to the tool executable. You can refer to the
   files being merged as well as the output file through these
   variables: ``$base``, ``$local``, ``$other``, ``$output``. The meaning
   of ``$local`` and ``$other`` can vary depending on which action is being
   performed. During and update or merge, ``$local`` represents the original
   state of the file, while ``$other`` represents the commit you are updating
   to or the commit you are merging with. During a rebase ``$local``
   represents the destination of the rebase, and ``$other`` represents the
   commit being rebased.
   (default: ``$local $base $other``)
 
 ``premerge``
   Attempt to run internal non-interactive 3-way merge tool before
   launching external tool.  Options are ``true``, ``false``, ``keep`` or
   ``keep-merge3``. The ``keep`` option will leave markers in the file if the
   premerge fails. The ``keep-merge3`` will do the same but include information
   about the base of the merge in the marker (see internal :merge3 in
   :hg:`help merge-tools`).
   (default: True)
 
 ``binary``
   This tool can merge binary files. (default: False, unless tool
   was selected by file pattern match)
 
 ``symlink``
   This tool can merge symlinks. (default: False)
 
 ``check``
   A list of merge success-checking options:
 
   ``changed``
     Ask whether merge was successful when the merged file shows no changes.
   ``conflicts``
     Check whether there are conflicts even though the tool reported success.
   ``prompt``
     Always prompt for merge success, regardless of success reported by tool.
 
 ``fixeol``
   Attempt to fix up EOL changes caused by the merge tool.
   (default: False)
 
 ``gui``
   This tool requires a graphical interface to run. (default: False)
 
 ``regkey``
   Windows registry key which describes install location of this
   tool. Mercurial will search for this key first under
   ``HKEY_CURRENT_USER`` and then under ``HKEY_LOCAL_MACHINE``.
   (default: None)
 
 ``regkeyalt``
   An alternate Windows registry key to try if the first key is not
   found.  The alternate key uses the same ``regname`` and ``regappend``
   semantics of the primary key.  The most common use for this key
   is to search for 32bit applications on 64bit operating systems.
   (default: None)
 
 ``regname``
   Name of value to read from specified registry key.
   (default: the unnamed (default) value)
 
 ``regappend``
   String to append to the value read from the registry, typically
   the executable name of the tool.
   (default: None)
 
 
 ``patch``
 ---------
 
 Settings used when applying patches, for instance through the 'import'
 command or with Mercurial Queues extension.
 
 ``eol``
     When set to 'strict' patch content and patched files end of lines
     are preserved. When set to ``lf`` or ``crlf``, both files end of
     lines are ignored when patching and the result line endings are
     normalized to either LF (Unix) or CRLF (Windows). When set to
     ``auto``, end of lines are again ignored while patching but line
     endings in patched files are normalized to their original setting
     on a per-file basis. If target file does not exist or has no end
     of line, patch line endings are preserved.
     (default: strict)
 
 ``fuzz``
     The number of lines of 'fuzz' to allow when applying patches. This
     controls how much context the patcher is allowed to ignore when
     trying to apply a patch.
     (default: 2)
 
 ``paths``
 ---------
 
 Assigns symbolic names and behavior to repositories.
 
 Options are symbolic names defining the URL or directory that is the
 location of the repository. Example::
 
     [paths]
     my_server = https://example.com/my_repo
     local_path = /home/me/repo
 
 These symbolic names can be used from the command line. To pull
 from ``my_server``: :hg:`pull my_server`. To push to ``local_path``:
 :hg:`push local_path`.
 
 Options containing colons (``:``) denote sub-options that can influence
 behavior for that specific path. Example::
 
     [paths]
     my_server = https://example.com/my_path
     my_server:pushurl = ssh://example.com/my_path
 
 The following sub-options can be defined:
 
 ``pushurl``
    The URL to use for push operations. If not defined, the location
    defined by the path's main entry is used.
 
 The following special named paths exist:
 
 ``default``
    The URL or directory to use when no source or remote is specified.
 
    :hg:`clone` will automatically define this path to the location the
    repository was cloned from.
 
 ``default-push``
    (deprecated) The URL or directory for the default :hg:`push` location.
    ``default:pushurl`` should be used instead.
 
 ``phases``
 ----------
 
 Specifies default handling of phases. See :hg:`help phases` for more
 information about working with phases.
 
 ``publish``
     Controls draft phase behavior when working as a server. When true,
     pushed changesets are set to public in both client and server and
     pulled or cloned changesets are set to public in the client.
     (default: True)
 
 ``new-commit``
     Phase of newly-created commits.
     (default: draft)
 
 ``checksubrepos``
     Check the phase of the current revision of each subrepository. Allowed
     values are "ignore", "follow" and "abort". For settings other than
     "ignore", the phase of the current revision of each subrepository is
     checked before committing the parent repository. If any of those phases is
     greater than the phase of the parent repository (e.g. if a subrepo is in a
     "secret" phase while the parent repo is in "draft" phase), the commit is
     either aborted (if checksubrepos is set to "abort") or the higher phase is
     used for the parent repository commit (if set to "follow").
     (default: follow)
 
 
 ``profiling``
 -------------
 
 Specifies profiling type, format, and file output. Two profilers are
 supported: an instrumenting profiler (named ``ls``), and a sampling
 profiler (named ``stat``).
 
 In this section description, 'profiling data' stands for the raw data
 collected during profiling, while 'profiling report' stands for a
 statistical text report generated from the profiling data. The
 profiling is done using lsprof.
 
 ``type``
     The type of profiler to use.
     (default: ls)
 
     ``ls``
       Use Python's built-in instrumenting profiler. This profiler
       works on all platforms, but each line number it reports is the
       first line of a function. This restriction makes it difficult to
       identify the expensive parts of a non-trivial function.
     ``stat``
       Use a third-party statistical profiler, statprof. This profiler
       currently runs only on Unix systems, and is most useful for
       profiling commands that run for longer than about 0.1 seconds.
 
 ``format``
     Profiling format.  Specific to the ``ls`` instrumenting profiler.
     (default: text)
 
     ``text``
       Generate a profiling report. When saving to a file, it should be
       noted that only the report is saved, and the profiling data is
       not kept.
     ``kcachegrind``
       Format profiling data for kcachegrind use: when saving to a
       file, the generated file can directly be loaded into
       kcachegrind.
 
 ``frequency``
     Sampling frequency.  Specific to the ``stat`` sampling profiler.
     (default: 1000)
 
 ``output``
     File path where profiling data or report should be saved. If the
     file exists, it is replaced. (default: None, data is printed on
     stderr)
 
 ``sort``
     Sort field.  Specific to the ``ls`` instrumenting profiler.
     One of ``callcount``, ``reccallcount``, ``totaltime`` and
     ``inlinetime``.
     (default: inlinetime)
 
 ``limit``
     Number of lines to show. Specific to the ``ls`` instrumenting profiler.
     (default: 30)
 
 ``nested``
     Show at most this number of lines of drill-down info after each main entry.
     This can help explain the difference between Total and Inline.
     Specific to the ``ls`` instrumenting profiler.
     (default: 5)
 
 ``progress``
 ------------
 
 Mercurial commands can draw progress bars that are as informative as
 possible. Some progress bars only offer indeterminate information, while others
 have a definite end point.
 
 ``delay``
     Number of seconds (float) before showing the progress bar. (default: 3)
 
 ``changedelay``
     Minimum delay before showing a new topic. When set to less than 3 * refresh,
     that value will be used instead. (default: 1)
 
 ``refresh``
     Time in seconds between refreshes of the progress bar. (default: 0.1)
 
 ``format``
     Format of the progress bar.
 
     Valid entries for the format field are ``topic``, ``bar``, ``number``,
     ``unit``, ``estimate``, speed, and item. item defaults to the last 20
     characters of the item, but this can be changed by adding either ``-<num>``
     which would take the last num characters, or ``+<num>`` for the first num
     characters.
 
     (default: Topic bar number estimate)
 
 ``width``
     If set, the maximum width of the progress information (that is, min(width,
     term width) will be used).
 
 ``clear-complete``
     Clear the progress bar after it's done. (default: True)
 
 ``disable``
     If true, don't show a progress bar.
 
 ``assume-tty``
     If true, ALWAYS show a progress bar, unless disable is given.
 
 ``revsetalias``
 ---------------
 
 Alias definitions for revsets. See :hg:`help revsets` for details.
 
 ``server``
 ----------
 
 Controls generic server settings.
 
 ``uncompressed``
     Whether to allow clients to clone a repository using the
     uncompressed streaming protocol. This transfers about 40% more
     data than a regular clone, but uses less memory and CPU on both
     server and client. Over a LAN (100 Mbps or better) or a very fast
     WAN, an uncompressed streaming clone is a lot faster (~10x) than a
     regular clone. Over most WAN connections (anything slower than
     about 6 Mbps), uncompressed streaming is slower, because of the
     extra data transfer overhead. This mode will also temporarily hold
     the write lock while determining what data to transfer.
     (default: True)
 
 ``preferuncompressed``
     When set, clients will try to use the uncompressed streaming
     protocol. (default: False)
 
 ``validate``
     Whether to validate the completeness of pushed changesets by
     checking that all new file revisions specified in manifests are
     present. (default: False)
 
 ``maxhttpheaderlen``
     Instruct HTTP clients not to send request headers longer than this
     many bytes. (default: 1024)
 
 ``bundle1``
     Whether to allow clients to push and pull using the legacy bundle1
     exchange format. (default: True)
 
 ``bundle1gd``
     Like ``bundle1` but only used if the repository is using the
     *generaldelta* storage format. (default: True)
 
 ``bundle1.push``
     Whether to allow clients to push using the legacy bundle1 exchange
     format. (default: True)
 
 ``bundle1gd.push``
     Like ``bundle1.push` but only used if the repository is using the
     *generaldelta* storage format. (default: True)
 
 ``bundle1.pull``
     Whether to allow clients to pull using the legacy bundle1 exchange
     format. (default: True)
 
 ``bundle1gd.pull``
     Like ``bundle1.pull` but only used if the repository is using the
     *generaldelta* storage format. (default: True)
 
     Large repositories using the *generaldelta* storage format should
     consider setting this option because converting *generaldelta*
     repositories to the exchange format required by the bundle1 data
     format can consume a lot of CPU.
 
 ``smtp``
 --------
 
 Configuration for extensions that need to send email messages.
 
 ``host``
     Host name of mail server, e.g. "mail.example.com".
 
 ``port``
     Optional. Port to connect to on mail server. (default: 465 if
     ``tls`` is smtps; 25 otherwise)
 
 ``tls``
     Optional. Method to enable TLS when connecting to mail server: starttls,
     smtps or none. (default: none)
 
 ``verifycert``
     Optional. Verification for the certificate of mail server, when
     ``tls`` is starttls or smtps. "strict", "loose" or False. For
     "strict" or "loose", the certificate is verified as same as the
     verification for HTTPS connections (see ``[hostfingerprints]`` and
     ``[web] cacerts`` also). For "strict", sending email is also
     aborted, if there is no configuration for mail server in
     ``[hostfingerprints]`` and ``[web] cacerts``.  --insecure for
     :hg:`email` overwrites this as "loose". (default: strict)
 
 ``username``
     Optional. User name for authenticating with the SMTP server.
     (default: None)
 
 ``password``
     Optional. Password for authenticating with the SMTP server. If not
     specified, interactive sessions will prompt the user for a
     password; non-interactive sessions will fail. (default: None)
 
 ``local_hostname``
     Optional. The hostname that the sender can use to identify
     itself to the MTA.
 
 
 ``subpaths``
 ------------
 
 Subrepository source URLs can go stale if a remote server changes name
 or becomes temporarily unavailable. This section lets you define
 rewrite rules of the form::
 
     <pattern> = <replacement>
 
 where ``pattern`` is a regular expression matching a subrepository
 source URL and ``replacement`` is the replacement string used to
 rewrite it. Groups can be matched in ``pattern`` and referenced in
 ``replacements``. For instance::
 
     http://server/(.*)-hg/ = http://hg.server/\1/
 
 rewrites ``http://server/foo-hg/`` into ``http://hg.server/foo/``.
 
 Relative subrepository paths are first made absolute, and the
 rewrite rules are then applied on the full (absolute) path. The rules
 are applied in definition order.
 
 ``trusted``
 -----------
 
 Mercurial will not use the settings in the
 ``.hg/hgrc`` file from a repository if it doesn't belong to a trusted
 user or to a trusted group, as various hgrc features allow arbitrary
 commands to be run. This issue is often encountered when configuring
 hooks or extensions for shared repositories or servers. However,
 the web interface will use some safe settings from the ``[web]``
 section.
 
 This section specifies what users and groups are trusted. The
 current user is always trusted. To trust everybody, list a user or a
 group with name ``*``. These settings must be placed in an
 *already-trusted file* to take effect, such as ``$HOME/.hgrc`` of the
 user or service running Mercurial.
 
 ``users``
   Comma-separated list of trusted users.
 
 ``groups``
   Comma-separated list of trusted groups.
 
 
 ``ui``
 ------
 
 User interface controls.
 
 ``archivemeta``
     Whether to include the .hg_archival.txt file containing meta data
     (hashes for the repository base and for tip) in archives created
     by the :hg:`archive` command or downloaded via hgweb.
     (default: True)
 
 ``askusername``
     Whether to prompt for a username when committing. If True, and
     neither ``$HGUSER`` nor ``$EMAIL`` has been specified, then the user will
     be prompted to enter a username. If no username is entered, the
     default ``USER@HOST`` is used instead.
     (default: False)
 
 ``clonebundlefallback``
     Whether failure to apply an advertised "clone bundle" from a server
     should result in fallback to a regular clone.
 
     This is disabled by default because servers advertising "clone
     bundles" often do so to reduce server load. If advertised bundles
     start mass failing and clients automatically fall back to a regular
     clone, this would add significant and unexpected load to the server
     since the server is expecting clone operations to be offloaded to
     pre-generated bundles. Failing fast (the default behavior) ensures
     clients don't overwhelm the server when "clone bundle" application
     fails.
 
     (default: False)
 
 ``commitsubrepos``
     Whether to commit modified subrepositories when committing the
     parent repository. If False and one subrepository has uncommitted
     changes, abort the commit.
     (default: False)
 
 ``debug``
     Print debugging information. (default: False)
 
 ``editor``
     The editor to use during a commit. (default: ``$EDITOR`` or ``vi``)
 
 ``fallbackencoding``
     Encoding to try if it's not possible to decode the changelog using
     UTF-8. (default: ISO-8859-1)
 
 ``graphnodetemplate``
     The template used to print changeset nodes in an ASCII revision graph.
     (default: ``{graphnode}``)
 
 ``ignore``
     A file to read per-user ignore patterns from. This file should be
     in the same format as a repository-wide .hgignore file. Filenames
     are relative to the repository root. This option supports hook syntax,
     so if you want to specify multiple ignore files, you can do so by
     setting something like ``ignore.other = ~/.hgignore2``. For details
     of the ignore file format, see the ``hgignore(5)`` man page.
 
 ``interactive``
     Allow to prompt the user. (default: True)
 
 ``logtemplate``
     Template string for commands that print changesets.
 
 ``merge``
     The conflict resolution program to use during a manual merge.
     For more information on merge tools see :hg:`help merge-tools`.
     For configuring merge tools see the ``[merge-tools]`` section.
 
 ``mergemarkers``
     Sets the merge conflict marker label styling. The ``detailed``
     style uses the ``mergemarkertemplate`` setting to style the labels.
     The ``basic`` style just uses 'local' and 'other' as the marker label.
     One of ``basic`` or ``detailed``.
     (default: ``basic``)
 
 ``mergemarkertemplate``
     The template used to print the commit description next to each conflict
     marker during merge conflicts. See :hg:`help templates` for the template
     format.
 
     Defaults to showing the hash, tags, branches, bookmarks, author, and
     the first line of the commit description.
 
     If you use non-ASCII characters in names for tags, branches, bookmarks,
     authors, and/or commit descriptions, you must pay attention to encodings of
     managed files. At template expansion, non-ASCII characters use the encoding
     specified by the ``--encoding`` global option, ``HGENCODING`` or other
     environment variables that govern your locale. If the encoding of the merge
     markers is different from the encoding of the merged files,
     serious problems may occur.
 
 ``origbackuppath``
     The path to a directory used to store generated .orig files. If the path is
     not a directory, one will be created.
 
 ``patch``
     An optional external tool that ``hg import`` and some extensions
     will use for applying patches. By default Mercurial uses an
     internal patch utility. The external tool must work as the common
     Unix ``patch`` program. In particular, it must accept a ``-p``
     argument to strip patch headers, a ``-d`` argument to specify the
     current directory, a file name to patch, and a patch file to take
     from stdin.
 
     It is possible to specify a patch tool together with extra
     arguments. For example, setting this option to ``patch --merge``
     will use the ``patch`` program with its 2-way merge option.
 
 ``portablefilenames``
     Check for portable filenames. Can be ``warn``, ``ignore`` or ``abort``.
     (default: ``warn``)
     If set to ``warn`` (or ``true``), a warning message is printed on POSIX
     platforms, if a file with a non-portable filename is added (e.g. a file
     with a name that can't be created on Windows because it contains reserved
     parts like ``AUX``, reserved characters like ``:``, or would cause a case
     collision with an existing file).
     If set to ``ignore`` (or ``false``), no warning is printed.
     If set to ``abort``, the command is aborted.
     On Windows, this configuration option is ignored and the command aborted.
 
 ``quiet``
     Reduce the amount of output printed. (default: False)
 
 ``remotecmd``
     Remote command to use for clone/push/pull operations. (default: ``hg``)
 
 ``report_untrusted``
     Warn if a ``.hg/hgrc`` file is ignored due to not being owned by a
     trusted user or group. (default: True)
 
 ``slash``
     Display paths using a slash (``/``) as the path separator. This
     only makes a difference on systems where the default path
     separator is not the slash character (e.g. Windows uses the
     backslash character (``\``)).
     (default: False)
 
 ``statuscopies``
     Display copies in the status command.
 
 ``ssh``
     Command to use for SSH connections. (default: ``ssh``)
 
 ``strict``
     Require exact command names, instead of allowing unambiguous
     abbreviations. (default: False)
 
 ``style``
     Name of style to use for command output.
 
 ``supportcontact``
     A URL where users should report a Mercurial traceback. Use this if you are a
     large organisation with its own Mercurial deployment process and crash
     reports should be addressed to your internal support.
 
 ``timeout``
     The timeout used when a lock is held (in seconds), a negative value
     means no timeout. (default: 600)
 
 ``traceback``
     Mercurial always prints a traceback when an unknown exception
     occurs. Setting this to True will make Mercurial print a traceback
     on all exceptions, even those recognized by Mercurial (such as
     IOError or MemoryError). (default: False)
 
 ``username``
     The committer of a changeset created when running "commit".
     Typically a person's name and email address, e.g. ``Fred Widget
     <[e-mail]>``. Environment variables in the
     username are expanded.
 
     (default: ``$EMAIL`` or ``username@hostname``. If the username in
     hgrc is empty, e.g. if the system admin set ``username =`` in the
     system hgrc, it has to be specified manually or in a different
     hgrc file)
 
 ``verbose``
     Increase the amount of output printed. (default: False)
 
 
 ``web``
 -------
 
 Web interface configuration. The settings in this section apply to
 both the builtin webserver (started by :hg:`serve`) and the script you
 run through a webserver (``hgweb.cgi`` and the derivatives for FastCGI
 and WSGI).
 
 The Mercurial webserver does no authentication (it does not prompt for
 usernames and passwords to validate *who* users are), but it does do
 authorization (it grants or denies access for *authenticated users*
 based on settings in this section). You must either configure your
 webserver to do authentication for you, or disable the authorization
 checks.
 
 For a quick setup in a trusted environment, e.g., a private LAN, where
 you want it to accept pushes from anybody, you can use the following
 command line::
 
     $ hg --config web.allow_push=* --config web.push_ssl=False serve
 
 Note that this will allow anybody to push anything to the server and
 that this should not be used for public servers.
 
 The full set of options is:
 
 ``accesslog``
     Where to output the access log. (default: stdout)
 
 ``address``
     Interface address to bind to. (default: all)
 
 ``allow_archive``
     List of archive format (bz2, gz, zip) allowed for downloading.
     (default: empty)
 
 ``allowbz2``
     (DEPRECATED) Whether to allow .tar.bz2 downloading of repository
     revisions.
     (default: False)
 
 ``allowgz``
     (DEPRECATED) Whether to allow .tar.gz downloading of repository
     revisions.
     (default: False)
 
 ``allowpull``
     Whether to allow pulling from the repository. (default: True)
 
 ``allow_push``
     Whether to allow pushing to the repository. If empty or not set,
     pushing is not allowed. If the special value ``*``, any remote
     user can push, including unauthenticated users. Otherwise, the
     remote user must have been authenticated, and the authenticated
     user name must be present in this list. The contents of the
     allow_push list are examined after the deny_push list.
 
 ``allow_read``
     If the user has not already been denied repository access due to
     the contents of deny_read, this list determines whether to grant
     repository access to the user. If this list is not empty, and the
     user is unauthenticated or not present in the list, then access is
     denied for the user. If the list is empty or not set, then access
     is permitted to all users by default. Setting allow_read to the
     special value ``*`` is equivalent to it not being set (i.e. access
     is permitted to all users). The contents of the allow_read list are
     examined after the deny_read list.
 
 ``allowzip``
     (DEPRECATED) Whether to allow .zip downloading of repository
     revisions. This feature creates temporary files.
     (default: False)
 
 ``archivesubrepos``
     Whether to recurse into subrepositories when archiving.
     (default: False)
 
 ``baseurl``
     Base URL to use when publishing URLs in other locations, so
     third-party tools like email notification hooks can construct
     URLs. Example: ``http://hgserver/repos/``.
 
 ``cacerts``
     Path to file containing a list of PEM encoded certificate
     authority certificates. Environment variables and ``~user``
     constructs are expanded in the filename. If specified on the
     client, then it will verify the identity of remote HTTPS servers
     with these certificates.
 
     This feature is only supported when using Python 2.6 or later. If you wish
     to use it with earlier versions of Python, install the backported
     version of the ssl library that is available from
     ``http://pypi.python.org``.
 
     To disable SSL verification temporarily, specify ``--insecure`` from
     command line.
 
     You can use OpenSSL's CA certificate file if your platform has
     one. On most Linux systems this will be
     ``/etc/ssl/certs/ca-certificates.crt``. Otherwise you will have to
     generate this file manually. The form must be as follows::
 
         -----BEGIN CERTIFICATE-----
         ... (certificate in base64 PEM encoding) ...
         -----END CERTIFICATE-----
         -----BEGIN CERTIFICATE-----
         ... (certificate in base64 PEM encoding) ...
         -----END CERTIFICATE-----
 
 ``cache``
     Whether to support caching in hgweb. (default: True)
 
 ``certificate``
     Certificate to use when running :hg:`serve`.
 
 ``collapse``
     With ``descend`` enabled, repositories in subdirectories are shown at
     a single level alongside repositories in the current path. With
     ``collapse`` also enabled, repositories residing at a deeper level than
     the current path are grouped behind navigable directory entries that
     lead to the locations of these repositories. In effect, this setting
     collapses each collection of repositories found within a subdirectory
     into a single entry for that subdirectory. (default: False)
 
 ``comparisoncontext``
     Number of lines of context to show in side-by-side file comparison. If
     negative or the value ``full``, whole files are shown. (default: 5)
 
     This setting can be overridden by a ``context`` request parameter to the
     ``comparison`` command, taking the same values.
 
 ``contact``
     Name or email address of the person in charge of the repository.
     (default: ui.username or ``$EMAIL`` or "unknown" if unset or empty)
 
 ``deny_push``
     Whether to deny pushing to the repository. If empty or not set,
     push is not denied. If the special value ``*``, all remote users are
     denied push. Otherwise, unauthenticated users are all denied, and
     any authenticated user name present in this list is also denied. The
     contents of the deny_push list are examined before the allow_push list.
 
 ``deny_read``
     Whether to deny reading/viewing of the repository. If this list is
     not empty, unauthenticated users are all denied, and any
     authenticated user name present in this list is also denied access to
     the repository. If set to the special value ``*``, all remote users
     are denied access (rarely needed ;). If deny_read is empty or not set,
     the determination of repository access depends on the presence and
     content of the allow_read list (see description). If both
     deny_read and allow_read are empty or not set, then access is
     permitted to all users by default. If the repository is being
     served via hgwebdir, denied users will not be able to see it in
     the list of repositories. The contents of the deny_read list have
     priority over (are examined before) the contents of the allow_read
     list.
 
 ``descend``
     hgwebdir indexes will not descend into subdirectories. Only repositories
     directly in the current path will be shown (other repositories are still
     available from the index corresponding to their containing path).
 
 ``description``
     Textual description of the repository's purpose or contents.
     (default: "unknown")
 
 ``encoding``
     Character encoding name. (default: the current locale charset)
     Example: "UTF-8".
 
 ``errorlog``
     Where to output the error log. (default: stderr)
 
 ``guessmime``
     Control MIME types for raw download of file content.
     Set to True to let hgweb guess the content type from the file
     extension. This will serve HTML files as ``text/html`` and might
     allow cross-site scripting attacks when serving untrusted
     repositories. (default: False)
 
 ``hidden``
     Whether to hide the repository in the hgwebdir index.
     (default: False)
 
 ``ipv6``
     Whether to use IPv6. (default: False)
 
 ``logoimg``
     File name of the logo image that some templates display on each page.
     The file name is relative to ``staticurl``. That is, the full path to
     the logo image is "staticurl/logoimg".
     If unset, ``hglogo.png`` will be used.
 
 ``logourl``
     Base URL to use for logos. If unset, ``https://mercurial-scm.org/``
     will be used.
 
 ``maxchanges``
     Maximum number of changes to list on the changelog. (default: 10)
 
 ``maxfiles``
     Maximum number of files to list per changeset. (default: 10)
 
 ``maxshortchanges``
     Maximum number of changes to list on the shortlog, graph or filelog
     pages. (default: 60)
 
 ``name``
     Repository name to use in the web interface.
     (default: current working directory)
 
 ``port``
     Port to listen on. (default: 8000)
 
 ``prefix``
     Prefix path to serve from. (default: '' (server root))
 
 ``push_ssl``
     Whether to require that inbound pushes be transported over SSL to
     prevent password sniffing. (default: True)
 
 ``refreshinterval``
     How frequently directory listings re-scan the filesystem for new
     repositories, in seconds. This is relevant when wildcards are used
     to define paths. Depending on how much filesystem traversal is
     required, refreshing may negatively impact performance.
 
     Values less than or equal to 0 always refresh.
     (default: 20)
 
 ``staticurl``
     Base URL to use for static files. If unset, static files (e.g. the
     hgicon.png favicon) will be served by the CGI script itself. Use
     this setting to serve them directly with the HTTP server.
     Example: ``http://hgserver/static/``.
 
 ``stripes``
     How many lines a "zebra stripe" should span in multi-line output.
     Set to 0 to disable. (default: 1)
 
 ``style``
     Which template map style to use. The available options are the names of
     subdirectories in the HTML templates path. (default: ``paper``)
     Example: ``monoblue``.
 
 ``templates``
     Where to find the HTML templates. The default path to the HTML templates
     can be obtained from ``hg debuginstall``.
 
 ``websub``
 ----------
 
 Web substitution filter definition. You can use this section to
 define a set of regular expression substitution patterns which
 let you automatically modify the hgweb server output.
 
 The default hgweb templates only apply these substitution patterns
 on the revision description fields. You can apply them anywhere
 you want when you create your own templates by adding calls to the
 "websub" filter (usually after calling the "escape" filter).
 
 This can be used, for example, to convert issue references to links
 to your issue tracker, or to convert "markdown-like" syntax into
 HTML (see the examples below).
 
 Each entry in this section names a substitution filter.
 The value of each entry defines the substitution expression itself.
 The websub expressions follow the old interhg extension syntax,
 which in turn imitates the Unix sed replacement syntax::
 
     patternname = s/SEARCH_REGEX/REPLACE_EXPRESSION/[i]
 
 You can use any separator other than "/". The final "i" is optional
 and indicates that the search must be case insensitive.
 
 Examples::
 
     [websub]
     issues = s|issue(\d+)|<a href="http://bts.example.org/issue\1">issue\1</a>|i
     italic = s/\b_(\S+)_\b/<i>\1<\/i>/
     bold = s/\*\b(\S+)\b\*/<b>\1<\/b>/
 
 ``worker``
 ----------
 
 Parallel master/worker configuration. We currently perform working
 directory updates in parallel on Unix-like systems, which greatly
 helps performance.
 
 ``numcpus``
     Number of CPUs to use for parallel operations. A zero or
     negative value is treated as ``use the default``.
     (default: 4 or the number of CPUs on the system, whichever is larger)

mercurial/merge.py

@@ -1,1560 +1,1573 b''
 # merge.py - directory-level update/merge handling for Mercurial
 #
 # Copyright 2006, 2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import errno
 import os
 import shutil
 import struct
 
 from .i18n import _
 from .node import (
     bin,
     hex,
     nullhex,
     nullid,
     nullrev,
 )
 from . import (
     copies,
     destutil,
     error,
     filemerge,
     obsolete,
     scmutil,
     subrepo,
     util,
     worker,
 )
 
 _pack = struct.pack
 _unpack = struct.unpack
 
 def _droponode(data):
     # used for compatibility for v1
     bits = data.split('\0')
     bits = bits[:-2] + bits[-1:]
     return '\0'.join(bits)
 
 class mergestate(object):
     '''track 3-way merge state of individual files
 
     The merge state is stored on disk when needed. Two files are used: one with
     an old format (version 1), and one with a new format (version 2). Version 2
     stores a superset of the data in version 1, including new kinds of records
     in the future. For more about the new format, see the documentation for
     `_readrecordsv2`.
 
     Each record can contain arbitrary content, and has an associated type. This
     `type` should be a letter. If `type` is uppercase, the record is mandatory:
     versions of Mercurial that don't support it should abort. If `type` is
     lowercase, the record can be safely ignored.
 
     Currently known records:
 
     L: the node of the "local" part of the merge (hexified version)
     O: the node of the "other" part of the merge (hexified version)
     F: a file to be merged entry
     C: a change/delete or delete/change conflict
     D: a file that the external merge driver will merge internally
        (experimental)
     m: the external merge driver defined for this merge plus its run state
        (experimental)
     X: unsupported mandatory record type (used in tests)
     x: unsupported advisory record type (used in tests)
 
     Merge driver run states (experimental):
     u: driver-resolved files unmarked -- needs to be run next time we're about
        to resolve or commit
     m: driver-resolved files marked -- only needs to be run before commit
     s: success/skipped -- does not need to be run any more
 
     '''
     statepathv1 = 'merge/state'
     statepathv2 = 'merge/state2'
 
     @staticmethod
     def clean(repo, node=None, other=None):
         """Initialize a brand new merge state, removing any existing state on
         disk."""
         ms = mergestate(repo)
         ms.reset(node, other)
         return ms
 
     @staticmethod
     def read(repo):
         """Initialize the merge state, reading it from disk."""
         ms = mergestate(repo)
         ms._read()
         return ms
 
     def __init__(self, repo):
         """Initialize the merge state.
 
         Do not use this directly! Instead call read() or clean()."""
         self._repo = repo
         self._dirty = False
 
     def reset(self, node=None, other=None):
         self._state = {}
         self._local = None
         self._other = None
         for var in ('localctx', 'otherctx'):
             if var in vars(self):
                 delattr(self, var)
         if node:
             self._local = node
             self._other = other
         self._readmergedriver = None
         if self.mergedriver:
             self._mdstate = 's'
         else:
             self._mdstate = 'u'
         shutil.rmtree(self._repo.join('merge'), True)
         self._results = {}
         self._dirty = False
 
     def _read(self):
         """Analyse each record content to restore a serialized state from disk
 
         This function process "record" entry produced by the de-serialization
         of on disk file.
         """
         self._state = {}
         self._local = None
         self._other = None
         for var in ('localctx', 'otherctx'):
             if var in vars(self):
                 delattr(self, var)
         self._readmergedriver = None
         self._mdstate = 's'
         unsupported = set()
         records = self._readrecords()
         for rtype, record in records:
             if rtype == 'L':
                 self._local = bin(record)
             elif rtype == 'O':
                 self._other = bin(record)
             elif rtype == 'm':
                 bits = record.split('\0', 1)
                 mdstate = bits[1]
                 if len(mdstate) != 1 or mdstate not in 'ums':
                     # the merge driver should be idempotent, so just rerun it
                     mdstate = 'u'
 
                 self._readmergedriver = bits[0]
                 self._mdstate = mdstate
             elif rtype in 'FDC':
                 bits = record.split('\0')
                 self._state[bits[0]] = bits[1:]
             elif not rtype.islower():
                 unsupported.add(rtype)
         self._results = {}
         self._dirty = False
 
         if unsupported:
             raise error.UnsupportedMergeRecords(unsupported)
 
     def _readrecords(self):
         """Read merge state from disk and return a list of record (TYPE, data)
 
         We read data from both v1 and v2 files and decide which one to use.
 
         V1 has been used by version prior to 2.9.1 and contains less data than
         v2. We read both versions and check if no data in v2 contradicts
         v1. If there is not contradiction we can safely assume that both v1
         and v2 were written at the same time and use the extract data in v2. If
         there is contradiction we ignore v2 content as we assume an old version
         of Mercurial has overwritten the mergestate file and left an old v2
         file around.
 
         returns list of record [(TYPE, data), ...]"""
         v1records = self._readrecordsv1()
         v2records = self._readrecordsv2()
         if self._v1v2match(v1records, v2records):
             return v2records
         else:
             # v1 file is newer than v2 file, use it
             # we have to infer the "other" changeset of the merge
             # we cannot do better than that with v1 of the format
             mctx = self._repo[None].parents()[-1]
             v1records.append(('O', mctx.hex()))
             # add place holder "other" file node information
             # nobody is using it yet so we do no need to fetch the data
             # if mctx was wrong `mctx[bits[-2]]` may fails.
             for idx, r in enumerate(v1records):
                 if r[0] == 'F':
                     bits = r[1].split('\0')
                     bits.insert(-2, '')
                     v1records[idx] = (r[0], '\0'.join(bits))
             return v1records
 
     def _v1v2match(self, v1records, v2records):
         oldv2 = set() # old format version of v2 record
         for rec in v2records:
             if rec[0] == 'L':
                 oldv2.add(rec)
             elif rec[0] == 'F':
                 # drop the onode data (not contained in v1)
                 oldv2.add(('F', _droponode(rec[1])))
         for rec in v1records:
             if rec not in oldv2:
                 return False
         else:
             return True
 
     def _readrecordsv1(self):
         """read on disk merge state for version 1 file
 
         returns list of record [(TYPE, data), ...]
 
         Note: the "F" data from this file are one entry short
               (no "other file node" entry)
         """
         records = []
         try:
             f = self._repo.vfs(self.statepathv1)
             for i, l in enumerate(f):
                 if i == 0:
                     records.append(('L', l[:-1]))
                 else:
                     records.append(('F', l[:-1]))
             f.close()
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
         return records
 
     def _readrecordsv2(self):
         """read on disk merge state for version 2 file
 
         This format is a list of arbitrary records of the form:
 
           [type][length][content]
 
         `type` is a single character, `length` is a 4 byte integer, and
         `content` is an arbitrary byte sequence of length `length`.
 
         Mercurial versions prior to 3.7 have a bug where if there are
         unsupported mandatory merge records, attempting to clear out the merge
         state with hg update --clean or similar aborts. The 't' record type
         works around that by writing out what those versions treat as an
         advisory record, but later versions interpret as special: the first
         character is the 'real' record type and everything onwards is the data.
 
         Returns list of records [(TYPE, data), ...]."""
         records = []
         try:
             f = self._repo.vfs(self.statepathv2)
             data = f.read()
             off = 0
             end = len(data)
             while off < end:
                 rtype = data[off]
                 off += 1
                 length = _unpack('>I', data[off:(off + 4)])[0]
                 off += 4
                 record = data[off:(off + length)]
                 off += length
                 if rtype == 't':
                     rtype, record = record[0], record[1:]
                 records.append((rtype, record))
             f.close()
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
         return records
 
     @util.propertycache
     def mergedriver(self):
         # protect against the following:
         # - A configures a malicious merge driver in their hgrc, then
         #   pauses the merge
         # - A edits their hgrc to remove references to the merge driver
         # - A gives a copy of their entire repo, including .hg, to B
         # - B inspects .hgrc and finds it to be clean
         # - B then continues the merge and the malicious merge driver
         #  gets invoked
         configmergedriver = self._repo.ui.config('experimental', 'mergedriver')
         if (self._readmergedriver is not None
             and self._readmergedriver != configmergedriver):
             raise error.ConfigError(
                 _("merge driver changed since merge started"),
                 hint=_("revert merge driver change or abort merge"))
 
         return configmergedriver
 
     @util.propertycache
     def localctx(self):
         if self._local is None:
             raise RuntimeError("localctx accessed but self._local isn't set")
         return self._repo[self._local]
 
     @util.propertycache
     def otherctx(self):
         if self._other is None:
             raise RuntimeError("localctx accessed but self._local isn't set")
         return self._repo[self._other]
 
     def active(self):
         """Whether mergestate is active.
 
         Returns True if there appears to be mergestate. This is a rough proxy
         for "is a merge in progress."
         """
         # Check local variables before looking at filesystem for performance
         # reasons.
         return bool(self._local) or bool(self._state) or \
                self._repo.vfs.exists(self.statepathv1) or \
                self._repo.vfs.exists(self.statepathv2)
 
     def commit(self):
         """Write current state on disk (if necessary)"""
         if self._dirty:
             records = self._makerecords()
             self._writerecords(records)
             self._dirty = False
 
     def _makerecords(self):
         records = []
         records.append(('L', hex(self._local)))
         records.append(('O', hex(self._other)))
         if self.mergedriver:
             records.append(('m', '\0'.join([
                 self.mergedriver, self._mdstate])))
         for d, v in self._state.iteritems():
             if v[0] == 'd':
                 records.append(('D', '\0'.join([d] + v)))
             # v[1] == local ('cd'), v[6] == other ('dc') -- not supported by
             # older versions of Mercurial
             elif v[1] == nullhex or v[6] == nullhex:
                 records.append(('C', '\0'.join([d] + v)))
             else:
                 records.append(('F', '\0'.join([d] + v)))
         return records
 
     def _writerecords(self, records):
         """Write current state on disk (both v1 and v2)"""
         self._writerecordsv1(records)
         self._writerecordsv2(records)
 
     def _writerecordsv1(self, records):
         """Write current state on disk in a version 1 file"""
         f = self._repo.vfs(self.statepathv1, 'w')
         irecords = iter(records)
         lrecords = irecords.next()
         assert lrecords[0] == 'L'
         f.write(hex(self._local) + '\n')
         for rtype, data in irecords:
             if rtype == 'F':
                 f.write('%s\n' % _droponode(data))
         f.close()
 
     def _writerecordsv2(self, records):
         """Write current state on disk in a version 2 file
 
         See the docstring for _readrecordsv2 for why we use 't'."""
         # these are the records that all version 2 clients can read
         whitelist = 'LOF'
         f = self._repo.vfs(self.statepathv2, 'w')
         for key, data in records:
             assert len(key) == 1
             if key not in whitelist:
                 key, data = 't', '%s%s' % (key, data)
             format = '>sI%is' % len(data)
             f.write(_pack(format, key, len(data), data))
         f.close()
 
     def add(self, fcl, fco, fca, fd):
         """add a new (potentially?) conflicting file the merge state
         fcl: file context for local,
         fco: file context for remote,
         fca: file context for ancestors,
         fd:  file path of the resulting merge.
 
         note: also write the local version to the `.hg/merge` directory.
         """
         if fcl.isabsent():
             hash = nullhex
         else:
             hash = util.sha1(fcl.path()).hexdigest()
             self._repo.vfs.write('merge/' + hash, fcl.data())
         self._state[fd] = ['u', hash, fcl.path(),
                            fca.path(), hex(fca.filenode()),
                            fco.path(), hex(fco.filenode()),
                            fcl.flags()]
         self._dirty = True
 
     def __contains__(self, dfile):
         return dfile in self._state
 
     def __getitem__(self, dfile):
         return self._state[dfile][0]
 
     def __iter__(self):
         return iter(sorted(self._state))
 
     def files(self):
         return self._state.keys()
 
     def mark(self, dfile, state):
         self._state[dfile][0] = state
         self._dirty = True
 
     def mdstate(self):
         return self._mdstate
 
     def unresolved(self):
         """Obtain the paths of unresolved files."""
 
         for f, entry in self._state.items():
             if entry[0] == 'u':
                 yield f
 
     def driverresolved(self):
         """Obtain the paths of driver-resolved files."""
 
         for f, entry in self._state.items():
             if entry[0] == 'd':
                 yield f
 
     def _resolve(self, preresolve, dfile, wctx, labels=None):
         """rerun merge process for file path `dfile`"""
         if self[dfile] in 'rd':
             return True, 0
         stateentry = self._state[dfile]
         state, hash, lfile, afile, anode, ofile, onode, flags = stateentry
         octx = self._repo[self._other]
         fcd = self._filectxorabsent(hash, wctx, dfile)
         fco = self._filectxorabsent(onode, octx, ofile)
         # TODO: move this to filectxorabsent
         fca = self._repo.filectx(afile, fileid=anode)
         # "premerge" x flags
         flo = fco.flags()
         fla = fca.flags()
         if 'x' in flags + flo + fla and 'l' not in flags + flo + fla:
             if fca.node() == nullid:
                 if preresolve:
                     self._repo.ui.warn(
                         _('warning: cannot merge flags for %s\n') % afile)
             elif flags == fla:
                 flags = flo
         if preresolve:
             # restore local
             if hash != nullhex:
                 f = self._repo.vfs('merge/' + hash)
                 self._repo.wwrite(dfile, f.read(), flags)
                 f.close()
             else:
                 self._repo.wvfs.unlinkpath(dfile, ignoremissing=True)
             complete, r, deleted = filemerge.premerge(self._repo, self._local,
                                                       lfile, fcd, fco, fca,
                                                       labels=labels)
         else:
             complete, r, deleted = filemerge.filemerge(self._repo, self._local,
                                                        lfile, fcd, fco, fca,
                                                        labels=labels)
         if r is None:
             # no real conflict
             del self._state[dfile]
             self._dirty = True
         elif not r:
             self.mark(dfile, 'r')
 
         if complete:
             action = None
             if deleted:
                 if fcd.isabsent():
                     # dc: local picked. Need to drop if present, which may
                     # happen on re-resolves.
                     action = 'f'
                 else:
                     # cd: remote picked (or otherwise deleted)
                     action = 'r'
             else:
                 if fcd.isabsent(): # dc: remote picked
                     action = 'g'
                 elif fco.isabsent(): # cd: local picked
                     if dfile in self.localctx:
                         action = 'am'
                     else:
                         action = 'a'
                 # else: regular merges (no action necessary)
             self._results[dfile] = r, action
 
         return complete, r
 
     def _filectxorabsent(self, hexnode, ctx, f):
         if hexnode == nullhex:
             return filemerge.absentfilectx(ctx, f)
         else:
             return ctx[f]
 
     def preresolve(self, dfile, wctx, labels=None):
         """run premerge process for dfile
 
         Returns whether the merge is complete, and the exit code."""
         return self._resolve(True, dfile, wctx, labels=labels)
 
     def resolve(self, dfile, wctx, labels=None):
         """run merge process (assuming premerge was run) for dfile
 
         Returns the exit code of the merge."""
         return self._resolve(False, dfile, wctx, labels=labels)[1]
 
     def counts(self):
         """return counts for updated, merged and removed files in this
         session"""
         updated, merged, removed = 0, 0, 0
         for r, action in self._results.itervalues():
             if r is None:
                 updated += 1
             elif r == 0:
                 if action == 'r':
                     removed += 1
                 else:
                     merged += 1
         return updated, merged, removed
 
     def unresolvedcount(self):
         """get unresolved count for this merge (persistent)"""
         return len([True for f, entry in self._state.iteritems()
                     if entry[0] == 'u'])
 
     def actions(self):
         """return lists of actions to perform on the dirstate"""
         actions = {'r': [], 'f': [], 'a': [], 'am': [], 'g': []}
         for f, (r, action) in self._results.iteritems():
             if action is not None:
                 actions[action].append((f, None, "merge result"))
         return actions
 
     def recordactions(self):
         """record remove/add/get actions in the dirstate"""
         branchmerge = self._repo.dirstate.p2() != nullid
         recordupdates(self._repo, self.actions(), branchmerge)
 
     def queueremove(self, f):
         """queues a file to be removed from the dirstate
 
         Meant for use by custom merge drivers."""
         self._results[f] = 0, 'r'
 
     def queueadd(self, f):
         """queues a file to be added to the dirstate
 
         Meant for use by custom merge drivers."""
         self._results[f] = 0, 'a'
 
     def queueget(self, f):
         """queues a file to be marked modified in the dirstate
 
         Meant for use by custom merge drivers."""
         self._results[f] = 0, 'g'
 
 def _checkunknownfile(repo, wctx, mctx, f, f2=None):
     if f2 is None:
         f2 = f
     return (repo.wvfs.isfileorlink(f)
         and repo.wvfs.audit.check(f)
         and repo.dirstate.normalize(f) not in repo.dirstate
         and mctx[f2].cmp(wctx[f]))
 
 def _checkunknownfiles(repo, wctx, mctx, force, actions):
     """
     Considers any actions that care about the presence of conflicting unknown
     files. For some actions, the result is to abort; for others, it is to
     choose a different action.
     """
     conflicts = set()
     if not force:
+        config = repo.ui.config('merge', 'checkunknown', default='abort')
+        valid = ['abort', 'ignore', 'warn']
+        if config not in valid:
+            validstr = ', '.join(["'" + v + "'" for v in valid])
+            raise error.ConfigError(_("merge.checkunknown not valid "
+                                      "('%s' is none of %s)")
+                                    % (config, validstr))
+
         for f, (m, args, msg) in actions.iteritems():
             if m in ('c', 'dc'):
                 if _checkunknownfile(repo, wctx, mctx, f):
                     conflicts.add(f)
             elif m == 'dg':
                 if _checkunknownfile(repo, wctx, mctx, f, args[0]):
                     conflicts.add(f)
 
-        for f in sorted(conflicts):
-            repo.ui.warn(_("%s: untracked file differs\n") % f)
-        if conflicts:
-            raise error.Abort(_("untracked files in working directory differ "
-                                "from files in requested revision"))
+        if config == 'abort':
+            for f in sorted(conflicts):
+                repo.ui.warn(_("%s: untracked file differs\n") % f)
+            if conflicts:
+                raise error.Abort(_("untracked files in working directory "
+                                    "differ from files in requested revision"))
+        elif config == 'warn':
+            for f in sorted(conflicts):
+                repo.ui.warn(_("%s: replacing untracked file\n") % f)
 
     for f, (m, args, msg) in actions.iteritems():
+        backup = f in conflicts
         if m == 'c':
             flags, = args
-            actions[f] = ('g', (flags, False), msg)
+            actions[f] = ('g', (flags, backup), msg)
         elif m == 'cm':
             fl2, anc = args
             different = _checkunknownfile(repo, wctx, mctx, f)
             if different:
                 actions[f] = ('m', (f, f, None, False, anc),
                               "remote differs from untracked local")
             else:
-                actions[f] = ('g', (fl2, False), "remote created")
+                actions[f] = ('g', (fl2, backup), "remote created")
 
 def _forgetremoved(wctx, mctx, branchmerge):
     """
     Forget removed files
 
     If we're jumping between revisions (as opposed to merging), and if
     neither the working directory nor the target rev has the file,
     then we need to remove it from the dirstate, to prevent the
     dirstate from listing the file when it is no longer in the
     manifest.
 
     If we're merging, and the other revision has removed a file
     that is not present in the working directory, we need to mark it
     as removed.
     """
 
     actions = {}
     m = 'f'
     if branchmerge:
         m = 'r'
     for f in wctx.deleted():
         if f not in mctx:
             actions[f] = m, None, "forget deleted"
 
     if not branchmerge:
         for f in wctx.removed():
             if f not in mctx:
                 actions[f] = 'f', None, "forget removed"
 
     return actions
 
 def _checkcollision(repo, wmf, actions):
     # build provisional merged manifest up
     pmmf = set(wmf)
 
     if actions:
         # k, dr, e and rd are no-op
         for m in 'a', 'am', 'f', 'g', 'cd', 'dc':
             for f, args, msg in actions[m]:
                 pmmf.add(f)
         for f, args, msg in actions['r']:
             pmmf.discard(f)
         for f, args, msg in actions['dm']:
             f2, flags = args
             pmmf.discard(f2)
             pmmf.add(f)
         for f, args, msg in actions['dg']:
             pmmf.add(f)
         for f, args, msg in actions['m']:
             f1, f2, fa, move, anc = args
             if move:
                 pmmf.discard(f1)
             pmmf.add(f)
 
     # check case-folding collision in provisional merged manifest
     foldmap = {}
     for f in sorted(pmmf):
         fold = util.normcase(f)
         if fold in foldmap:
             raise error.Abort(_("case-folding collision between %s and %s")
                              % (f, foldmap[fold]))
         foldmap[fold] = f
 
     # check case-folding of directories
     foldprefix = unfoldprefix = lastfull = ''
     for fold, f in sorted(foldmap.items()):
         if fold.startswith(foldprefix) and not f.startswith(unfoldprefix):
             # the folded prefix matches but actual casing is different
             raise error.Abort(_("case-folding collision between "
                                 "%s and directory of %s") % (lastfull, f))
         foldprefix = fold + '/'
         unfoldprefix = f + '/'
         lastfull = f
 
 def driverpreprocess(repo, ms, wctx, labels=None):
     """run the preprocess step of the merge driver, if any
 
     This is currently not implemented -- it's an extension point."""
     return True
 
 def driverconclude(repo, ms, wctx, labels=None):
     """run the conclude step of the merge driver, if any
 
     This is currently not implemented -- it's an extension point."""
     return True
 
 def manifestmerge(repo, wctx, p2, pa, branchmerge, force, matcher,
                   acceptremote, followcopies):
     """
     Merge p1 and p2 with ancestor pa and generate merge action list
 
     branchmerge and force are as passed in to update
     matcher = matcher to filter file lists
     acceptremote = accept the incoming changes without prompting
     """
     if matcher is not None and matcher.always():
         matcher = None
 
     copy, movewithdir, diverge, renamedelete = {}, {}, {}, {}
 
     # manifests fetched in order are going to be faster, so prime the caches
     [x.manifest() for x in
      sorted(wctx.parents() + [p2, pa], key=lambda x: x.rev())]
 
     if followcopies:
         ret = copies.mergecopies(repo, wctx, p2, pa)
         copy, movewithdir, diverge, renamedelete = ret
 
     repo.ui.note(_("resolving manifests\n"))
     repo.ui.debug(" branchmerge: %s, force: %s, partial: %s\n"
                   % (bool(branchmerge), bool(force), bool(matcher)))
     repo.ui.debug(" ancestor: %s, local: %s, remote: %s\n" % (pa, wctx, p2))
 
     m1, m2, ma = wctx.manifest(), p2.manifest(), pa.manifest()
     copied = set(copy.values())
     copied.update(movewithdir.values())
 
     if '.hgsubstate' in m1:
         # check whether sub state is modified
         for s in sorted(wctx.substate):
             if wctx.sub(s).dirty():
                 m1['.hgsubstate'] += '+'
                 break
 
     # Compare manifests
     if matcher is not None:
         m1 = m1.matches(matcher)
         m2 = m2.matches(matcher)
     diff = m1.diff(m2)
 
     actions = {}
     for f, ((n1, fl1), (n2, fl2)) in diff.iteritems():
         if n1 and n2: # file exists on both local and remote side
             if f not in ma:
                 fa = copy.get(f, None)
                 if fa is not None:
                     actions[f] = ('m', (f, f, fa, False, pa.node()),
                                   "both renamed from " + fa)
                 else:
                     actions[f] = ('m', (f, f, None, False, pa.node()),
                                   "both created")
             else:
                 a = ma[f]
                 fla = ma.flags(f)
                 nol = 'l' not in fl1 + fl2 + fla
                 if n2 == a and fl2 == fla:
                     actions[f] = ('k' , (), "remote unchanged")
                 elif n1 == a and fl1 == fla: # local unchanged - use remote
                     if n1 == n2: # optimization: keep local content
                         actions[f] = ('e', (fl2,), "update permissions")
                     else:
                         actions[f] = ('g', (fl2, False), "remote is newer")
                 elif nol and n2 == a: # remote only changed 'x'
                     actions[f] = ('e', (fl2,), "update permissions")
                 elif nol and n1 == a: # local only changed 'x'
                     actions[f] = ('g', (fl1, False), "remote is newer")
                 else: # both changed something
                     actions[f] = ('m', (f, f, f, False, pa.node()),
                                    "versions differ")
         elif n1: # file exists only on local side
             if f in copied:
                 pass # we'll deal with it on m2 side
             elif f in movewithdir: # directory rename, move local
                 f2 = movewithdir[f]
                 if f2 in m2:
                     actions[f2] = ('m', (f, f2, None, True, pa.node()),
                                    "remote directory rename, both created")
                 else:
                     actions[f2] = ('dm', (f, fl1),
                                    "remote directory rename - move from " + f)
             elif f in copy:
                 f2 = copy[f]
                 actions[f] = ('m', (f, f2, f2, False, pa.node()),
                               "local copied/moved from " + f2)
             elif f in ma: # clean, a different, no remote
                 if n1 != ma[f]:
                     if acceptremote:
                         actions[f] = ('r', None, "remote delete")
                     else:
                         actions[f] = ('cd', (f, None, f, False, pa.node()),
                                       "prompt changed/deleted")
                 elif n1[20:] == 'a':
                     # This extra 'a' is added by working copy manifest to mark
                     # the file as locally added. We should forget it instead of
                     # deleting it.
                     actions[f] = ('f', None, "remote deleted")
                 else:
                     actions[f] = ('r', None, "other deleted")
         elif n2: # file exists only on remote side
             if f in copied:
                 pass # we'll deal with it on m1 side
             elif f in movewithdir:
                 f2 = movewithdir[f]
                 if f2 in m1:
                     actions[f2] = ('m', (f2, f, None, False, pa.node()),
                                    "local directory rename, both created")
                 else:
                     actions[f2] = ('dg', (f, fl2),
                                    "local directory rename - get from " + f)
             elif f in copy:
                 f2 = copy[f]
                 if f2 in m2:
                     actions[f] = ('m', (f2, f, f2, False, pa.node()),
                                   "remote copied from " + f2)
                 else:
                     actions[f] = ('m', (f2, f, f2, True, pa.node()),
                                   "remote moved from " + f2)
             elif f not in ma:
                 # local unknown, remote created: the logic is described by the
                 # following table:
                 #
                 # force  branchmerge  different  |  action
                 #   n         *           *      |   create
                 #   y         n           *      |   create
                 #   y         y           n      |   create
                 #   y         y           y      |   merge
                 #
                 # Checking whether the files are different is expensive, so we
                 # don't do that when we can avoid it.
                 if not force:
                     actions[f] = ('c', (fl2,), "remote created")
                 elif not branchmerge:
                     actions[f] = ('c', (fl2,), "remote created")
                 else:
                     actions[f] = ('cm', (fl2, pa.node()),
                                   "remote created, get or merge")
             elif n2 != ma[f]:
                 if acceptremote:
                     actions[f] = ('c', (fl2,), "remote recreating")
                 else:
                     actions[f] = ('dc', (None, f, f, False, pa.node()),
                                   "prompt deleted/changed")
 
     return actions, diverge, renamedelete
 
 def _resolvetrivial(repo, wctx, mctx, ancestor, actions):
     """Resolves false conflicts where the nodeid changed but the content
        remained the same."""
 
     for f, (m, args, msg) in actions.items():
         if m == 'cd' and f in ancestor and not wctx[f].cmp(ancestor[f]):
             # local did change but ended up with same content
             actions[f] = 'r', None, "prompt same"
         elif m == 'dc' and f in ancestor and not mctx[f].cmp(ancestor[f]):
             # remote did change but ended up with same content
             del actions[f] # don't get = keep local deleted
 
 def calculateupdates(repo, wctx, mctx, ancestors, branchmerge, force,
                      acceptremote, followcopies, matcher=None):
     "Calculate the actions needed to merge mctx into wctx using ancestors"
     if len(ancestors) == 1: # default
         actions, diverge, renamedelete = manifestmerge(
             repo, wctx, mctx, ancestors[0], branchmerge, force, matcher,
             acceptremote, followcopies)
         _checkunknownfiles(repo, wctx, mctx, force, actions)
 
     else: # only when merge.preferancestor=* - the default
         repo.ui.note(
             _("note: merging %s and %s using bids from ancestors %s\n") %
             (wctx, mctx, _(' and ').join(str(anc) for anc in ancestors)))
 
         # Call for bids
         fbids = {} # mapping filename to bids (action method to list af actions)
         diverge, renamedelete = None, None
         for ancestor in ancestors:
             repo.ui.note(_('\ncalculating bids for ancestor %s\n') % ancestor)
             actions, diverge1, renamedelete1 = manifestmerge(
                 repo, wctx, mctx, ancestor, branchmerge, force, matcher,
                 acceptremote, followcopies)
             _checkunknownfiles(repo, wctx, mctx, force, actions)
 
             # Track the shortest set of warning on the theory that bid
             # merge will correctly incorporate more information
             if diverge is None or len(diverge1) < len(diverge):
                 diverge = diverge1
             if renamedelete is None or len(renamedelete) < len(renamedelete1):
                 renamedelete = renamedelete1
 
             for f, a in sorted(actions.iteritems()):
                 m, args, msg = a
                 repo.ui.debug(' %s: %s -> %s\n' % (f, msg, m))
                 if f in fbids:
                     d = fbids[f]
                     if m in d:
                         d[m].append(a)
                     else:
                         d[m] = [a]
                 else:
                     fbids[f] = {m: [a]}
 
         # Pick the best bid for each file
         repo.ui.note(_('\nauction for merging merge bids\n'))
         actions = {}
         for f, bids in sorted(fbids.items()):
             # bids is a mapping from action method to list af actions
             # Consensus?
             if len(bids) == 1: # all bids are the same kind of method
                 m, l = bids.items()[0]
                 if all(a == l[0] for a in l[1:]): # len(bids) is > 1
                     repo.ui.note(" %s: consensus for %s\n" % (f, m))
                     actions[f] = l[0]
                     continue
             # If keep is an option, just do it.
             if 'k' in bids:
                 repo.ui.note(" %s: picking 'keep' action\n" % f)
                 actions[f] = bids['k'][0]
                 continue
             # If there are gets and they all agree [how could they not?], do it.
             if 'g' in bids:
                 ga0 = bids['g'][0]
                 if all(a == ga0 for a in bids['g'][1:]):
                     repo.ui.note(" %s: picking 'get' action\n" % f)
                     actions[f] = ga0
                     continue
             # TODO: Consider other simple actions such as mode changes
             # Handle inefficient democrazy.
             repo.ui.note(_(' %s: multiple bids for merge action:\n') % f)
             for m, l in sorted(bids.items()):
                 for _f, args, msg in l:
                     repo.ui.note('  %s -> %s\n' % (msg, m))
             # Pick random action. TODO: Instead, prompt user when resolving
             m, l = bids.items()[0]
             repo.ui.warn(_(' %s: ambiguous merge - picked %s action\n') %
                          (f, m))
             actions[f] = l[0]
             continue
         repo.ui.note(_('end of auction\n\n'))
 
     _resolvetrivial(repo, wctx, mctx, ancestors[0], actions)
 
     if wctx.rev() is None:
         fractions = _forgetremoved(wctx, mctx, branchmerge)
         actions.update(fractions)
 
     return actions, diverge, renamedelete
 
 def batchremove(repo, actions):
     """apply removes to the working directory
 
     yields tuples for progress updates
     """
     verbose = repo.ui.verbose
     unlink = util.unlinkpath
     wjoin = repo.wjoin
     audit = repo.wvfs.audit
     i = 0
     for f, args, msg in actions:
         repo.ui.debug(" %s: %s -> r\n" % (f, msg))
         if verbose:
             repo.ui.note(_("removing %s\n") % f)
         audit(f)
         try:
             unlink(wjoin(f), ignoremissing=True)
         except OSError as inst:
             repo.ui.warn(_("update failed to remove %s: %s!\n") %
                          (f, inst.strerror))
         if i == 100:
             yield i, f
             i = 0
         i += 1
     if i > 0:
         yield i, f
 
 def batchget(repo, mctx, actions):
     """apply gets to the working directory
 
     mctx is the context to get from
 
     yields tuples for progress updates
     """
     verbose = repo.ui.verbose
     fctx = mctx.filectx
     wwrite = repo.wwrite
     ui = repo.ui
     i = 0
     for f, (flags, backup), msg in actions:
         repo.ui.debug(" %s: %s -> g\n" % (f, msg))
         if verbose:
             repo.ui.note(_("getting %s\n") % f)
 
         if backup:
             absf = repo.wjoin(f)
             orig = scmutil.origpath(ui, repo, absf)
             try:
                 # TODO Mercurial has always aborted if an untracked directory
                 # is replaced by a tracked file, or generally with
                 # file/directory merges. This needs to be sorted out.
                 if repo.wvfs.isfileorlink(f):
                     util.rename(absf, orig)
             except OSError as e:
                 if e.errno != errno.ENOENT:
                     raise
 
         wwrite(f, fctx(f).data(), flags)
         if i == 100:
             yield i, f
             i = 0
         i += 1
     if i > 0:
         yield i, f
 
 def applyupdates(repo, actions, wctx, mctx, overwrite, labels=None):
     """apply the merge action list to the working directory
 
     wctx is the working copy context
     mctx is the context to be merged into the working copy
 
     Return a tuple of counts (updated, merged, removed, unresolved) that
     describes how many files were affected by the update.
     """
 
     updated, merged, removed = 0, 0, 0
     ms = mergestate.clean(repo, wctx.p1().node(), mctx.node())
     moves = []
     for m, l in actions.items():
         l.sort()
 
     # 'cd' and 'dc' actions are treated like other merge conflicts
     mergeactions = sorted(actions['cd'])
     mergeactions.extend(sorted(actions['dc']))
     mergeactions.extend(actions['m'])
     for f, args, msg in mergeactions:
         f1, f2, fa, move, anc = args
         if f == '.hgsubstate': # merged internally
             continue
         if f1 is None:
             fcl = filemerge.absentfilectx(wctx, fa)
         else:
             repo.ui.debug(" preserving %s for resolve of %s\n" % (f1, f))
             fcl = wctx[f1]
         if f2 is None:
             fco = filemerge.absentfilectx(mctx, fa)
         else:
             fco = mctx[f2]
         actx = repo[anc]
         if fa in actx:
             fca = actx[fa]
         else:
             # TODO: move to absentfilectx
             fca = repo.filectx(f1, fileid=nullrev)
         ms.add(fcl, fco, fca, f)
         if f1 != f and move:
             moves.append(f1)
 
     audit = repo.wvfs.audit
     _updating = _('updating')
     _files = _('files')
     progress = repo.ui.progress
 
     # remove renamed files after safely stored
     for f in moves:
         if os.path.lexists(repo.wjoin(f)):
             repo.ui.debug("removing %s\n" % f)
             audit(f)
             util.unlinkpath(repo.wjoin(f))
 
     numupdates = sum(len(l) for m, l in actions.items() if m != 'k')
 
     if [a for a in actions['r'] if a[0] == '.hgsubstate']:
         subrepo.submerge(repo, wctx, mctx, wctx, overwrite)
 
     # remove in parallel (must come first)
     z = 0
     prog = worker.worker(repo.ui, 0.001, batchremove, (repo,), actions['r'])
     for i, item in prog:
         z += i
         progress(_updating, z, item=item, total=numupdates, unit=_files)
     removed = len(actions['r'])
 
     # get in parallel
     prog = worker.worker(repo.ui, 0.001, batchget, (repo, mctx), actions['g'])
     for i, item in prog:
         z += i
         progress(_updating, z, item=item, total=numupdates, unit=_files)
     updated = len(actions['g'])
 
     if [a for a in actions['g'] if a[0] == '.hgsubstate']:
         subrepo.submerge(repo, wctx, mctx, wctx, overwrite)
 
     # forget (manifest only, just log it) (must come first)
     for f, args, msg in actions['f']:
         repo.ui.debug(" %s: %s -> f\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
 
     # re-add (manifest only, just log it)
     for f, args, msg in actions['a']:
         repo.ui.debug(" %s: %s -> a\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
 
     # re-add/mark as modified (manifest only, just log it)
     for f, args, msg in actions['am']:
         repo.ui.debug(" %s: %s -> am\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
 
     # keep (noop, just log it)
     for f, args, msg in actions['k']:
         repo.ui.debug(" %s: %s -> k\n" % (f, msg))
         # no progress
 
     # directory rename, move local
     for f, args, msg in actions['dm']:
         repo.ui.debug(" %s: %s -> dm\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
         f0, flags = args
         repo.ui.note(_("moving %s to %s\n") % (f0, f))
         audit(f)
         repo.wwrite(f, wctx.filectx(f0).data(), flags)
         util.unlinkpath(repo.wjoin(f0))
         updated += 1
 
     # local directory rename, get
     for f, args, msg in actions['dg']:
         repo.ui.debug(" %s: %s -> dg\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
         f0, flags = args
         repo.ui.note(_("getting %s to %s\n") % (f0, f))
         repo.wwrite(f, mctx.filectx(f0).data(), flags)
         updated += 1
 
     # exec
     for f, args, msg in actions['e']:
         repo.ui.debug(" %s: %s -> e\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
         flags, = args
         audit(f)
         util.setflags(repo.wjoin(f), 'l' in flags, 'x' in flags)
         updated += 1
 
     # the ordering is important here -- ms.mergedriver will raise if the merge
     # driver has changed, and we want to be able to bypass it when overwrite is
     # True
     usemergedriver = not overwrite and mergeactions and ms.mergedriver
 
     if usemergedriver:
         ms.commit()
         proceed = driverpreprocess(repo, ms, wctx, labels=labels)
         # the driver might leave some files unresolved
         unresolvedf = set(ms.unresolved())
         if not proceed:
             # XXX setting unresolved to at least 1 is a hack to make sure we
             # error out
             return updated, merged, removed, max(len(unresolvedf), 1)
         newactions = []
         for f, args, msg in mergeactions:
             if f in unresolvedf:
                 newactions.append((f, args, msg))
         mergeactions = newactions
 
     # premerge
     tocomplete = []
     for f, args, msg in mergeactions:
         repo.ui.debug(" %s: %s -> m (premerge)\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
         if f == '.hgsubstate': # subrepo states need updating
             subrepo.submerge(repo, wctx, mctx, wctx.ancestor(mctx),
                              overwrite)
             continue
         audit(f)
         complete, r = ms.preresolve(f, wctx, labels=labels)
         if not complete:
             numupdates += 1
             tocomplete.append((f, args, msg))
 
     # merge
     for f, args, msg in tocomplete:
         repo.ui.debug(" %s: %s -> m (merge)\n" % (f, msg))
         z += 1
         progress(_updating, z, item=f, total=numupdates, unit=_files)
         ms.resolve(f, wctx, labels=labels)
 
     ms.commit()
 
     unresolved = ms.unresolvedcount()
 
     if usemergedriver and not unresolved and ms.mdstate() != 's':
         if not driverconclude(repo, ms, wctx, labels=labels):
             # XXX setting unresolved to at least 1 is a hack to make sure we
             # error out
             unresolved = max(unresolved, 1)
 
         ms.commit()
 
     msupdated, msmerged, msremoved = ms.counts()
     updated += msupdated
     merged += msmerged
     removed += msremoved
 
     extraactions = ms.actions()
     for k, acts in extraactions.iteritems():
         actions[k].extend(acts)
 
     progress(_updating, None, total=numupdates, unit=_files)
 
     return updated, merged, removed, unresolved
 
 def recordupdates(repo, actions, branchmerge):
     "record merge actions to the dirstate"
     # remove (must come first)
     for f, args, msg in actions.get('r', []):
         if branchmerge:
             repo.dirstate.remove(f)
         else:
             repo.dirstate.drop(f)
 
     # forget (must come first)
     for f, args, msg in actions.get('f', []):
         repo.dirstate.drop(f)
 
     # re-add
     for f, args, msg in actions.get('a', []):
         repo.dirstate.add(f)
 
     # re-add/mark as modified
     for f, args, msg in actions.get('am', []):
         if branchmerge:
             repo.dirstate.normallookup(f)
         else:
             repo.dirstate.add(f)
 
     # exec change
     for f, args, msg in actions.get('e', []):
         repo.dirstate.normallookup(f)
 
     # keep
     for f, args, msg in actions.get('k', []):
         pass
 
     # get
     for f, args, msg in actions.get('g', []):
         if branchmerge:
             repo.dirstate.otherparent(f)
         else:
             repo.dirstate.normal(f)
 
     # merge
     for f, args, msg in actions.get('m', []):
         f1, f2, fa, move, anc = args
         if branchmerge:
             # We've done a branch merge, mark this file as merged
             # so that we properly record the merger later
             repo.dirstate.merge(f)
             if f1 != f2: # copy/rename
                 if move:
                     repo.dirstate.remove(f1)
                 if f1 != f:
                     repo.dirstate.copy(f1, f)
                 else:
                     repo.dirstate.copy(f2, f)
         else:
             # We've update-merged a locally modified file, so
             # we set the dirstate to emulate a normal checkout
             # of that file some time in the past. Thus our
             # merge will appear as a normal local file
             # modification.
             if f2 == f: # file not locally copied/moved
                 repo.dirstate.normallookup(f)
             if move:
                 repo.dirstate.drop(f1)
 
     # directory rename, move local
     for f, args, msg in actions.get('dm', []):
         f0, flag = args
         if branchmerge:
             repo.dirstate.add(f)
             repo.dirstate.remove(f0)
             repo.dirstate.copy(f0, f)
         else:
             repo.dirstate.normal(f)
             repo.dirstate.drop(f0)
 
     # directory rename, get
     for f, args, msg in actions.get('dg', []):
         f0, flag = args
         if branchmerge:
             repo.dirstate.add(f)
             repo.dirstate.copy(f0, f)
         else:
             repo.dirstate.normal(f)
 
 def update(repo, node, branchmerge, force, ancestor=None,
            mergeancestor=False, labels=None, matcher=None):
     """
     Perform a merge between the working directory and the given node
 
     node = the node to update to, or None if unspecified
     branchmerge = whether to merge between branches
     force = whether to force branch merging or file overwriting
     matcher = a matcher to filter file lists (dirstate not updated)
     mergeancestor = whether it is merging with an ancestor. If true,
       we should accept the incoming changes for any prompts that occur.
       If false, merging with an ancestor (fast-forward) is only allowed
       between different named branches. This flag is used by rebase extension
       as a temporary fix and should be avoided in general.
 
     The table below shows all the behaviors of the update command
     given the -c and -C or no options, whether the working directory
     is dirty, whether a revision is specified, and the relationship of
     the parent rev to the target rev (linear, on the same named
     branch, or on another named branch).
 
     This logic is tested by test-update-branches.t.
 
     -c  -C  dirty  rev  |  linear      same    cross
      n   n    n     n   |    ok        (1)       x
      n   n    n     y   |    ok        ok       ok
      n   n    y     n   |   merge      (2)      (2)
      n   n    y     y   |   merge      (3)      (3)
      n   y    *     *   |   discard   discard   discard
      y   n    y     *   |    (4)       (4)      (4)
      y   n    n     *   |    ok        ok       ok
      y   y    *     *   |    (5)       (5)      (5)
 
     x = can't happen
     * = don't-care
     1 = abort: not a linear update (merge or update --check to force update)
     2 = abort: uncommitted changes (commit and merge, or update --clean to
                  discard changes)
     3 = abort: uncommitted changes (commit or update --clean to discard changes)
     4 = abort: uncommitted changes (checked in commands.py)
     5 = incompatible options (checked in commands.py)
 
     Return the same tuple as applyupdates().
     """
 
     onode = node
     wlock = repo.wlock()
     # If we're doing a partial update, we need to skip updating
     # the dirstate, so make a note of any partial-ness to the
     # update here.
     if matcher is None or matcher.always():
         partial = False
     else:
         partial = True
     try:
         wc = repo[None]
         pl = wc.parents()
         p1 = pl[0]
         pas = [None]
         if ancestor is not None:
             pas = [repo[ancestor]]
 
         if node is None:
             if (repo.ui.configbool('devel', 'all-warnings')
                     or repo.ui.configbool('devel', 'oldapi')):
                 repo.ui.develwarn('update with no target')
             rev, _mark, _act = destutil.destupdate(repo)
             node = repo[rev].node()
 
         overwrite = force and not branchmerge
 
         p2 = repo[node]
         if pas[0] is None:
             if repo.ui.configlist('merge', 'preferancestor', ['*']) == ['*']:
                 cahs = repo.changelog.commonancestorsheads(p1.node(), p2.node())
                 pas = [repo[anc] for anc in (sorted(cahs) or [nullid])]
             else:
                 pas = [p1.ancestor(p2, warn=branchmerge)]
 
         fp1, fp2, xp1, xp2 = p1.node(), p2.node(), str(p1), str(p2)
 
         ### check phase
         if not overwrite:
             if len(pl) > 1:
                 raise error.Abort(_("outstanding uncommitted merge"))
             ms = mergestate.read(repo)
             if list(ms.unresolved()):
                 raise error.Abort(_("outstanding merge conflicts"))
         if branchmerge:
             if pas == [p2]:
                 raise error.Abort(_("merging with a working directory ancestor"
                                    " has no effect"))
             elif pas == [p1]:
                 if not mergeancestor and p1.branch() == p2.branch():
                     raise error.Abort(_("nothing to merge"),
                                      hint=_("use 'hg update' "
                                             "or check 'hg heads'"))
             if not force and (wc.files() or wc.deleted()):
                 raise error.Abort(_("uncommitted changes"),
                                  hint=_("use 'hg status' to list changes"))
             for s in sorted(wc.substate):
                 wc.sub(s).bailifchanged()
 
         elif not overwrite:
             if p1 == p2: # no-op update
                 # call the hooks and exit early
                 repo.hook('preupdate', throw=True, parent1=xp2, parent2='')
                 repo.hook('update', parent1=xp2, parent2='', error=0)
                 return 0, 0, 0, 0
 
             if pas not in ([p1], [p2]):  # nonlinear
                 dirty = wc.dirty(missing=True)
                 if dirty or onode is None:
                     # Branching is a bit strange to ensure we do the minimal
                     # amount of call to obsolete.background.
                     foreground = obsolete.foreground(repo, [p1.node()])
                     # note: the <node> variable contains a random identifier
                     if repo[node].node() in foreground:
                         pas = [p1]  # allow updating to successors
                     elif dirty:
                         msg = _("uncommitted changes")
                         if onode is None:
                             hint = _("commit and merge, or update --clean to"
                                      " discard changes")
                         else:
                             hint = _("commit or update --clean to discard"
                                      " changes")
                         raise error.Abort(msg, hint=hint)
                     else:  # node is none
                         msg = _("not a linear update")
                         hint = _("merge or update --check to force update")
                         raise error.Abort(msg, hint=hint)
                 else:
                     # Allow jumping branches if clean and specific rev given
                     pas = [p1]
 
         # deprecated config: merge.followcopies
         followcopies = False
         if overwrite:
             pas = [wc]
         elif pas == [p2]: # backwards
             pas = [wc.p1()]
         elif not branchmerge and not wc.dirty(missing=True):
             pass
         elif pas[0] and repo.ui.configbool('merge', 'followcopies', True):
             followcopies = True
 
         ### calculate phase
         actionbyfile, diverge, renamedelete = calculateupdates(
             repo, wc, p2, pas, branchmerge, force, mergeancestor,
             followcopies, matcher=matcher)
         # Convert to dictionary-of-lists format
         actions = dict((m, []) for m in 'a am f g cd dc r dm dg m e k'.split())
         for f, (m, args, msg) in actionbyfile.iteritems():
             if m not in actions:
                 actions[m] = []
             actions[m].append((f, args, msg))
 
         if not util.checkcase(repo.path):
             # check collision between files only in p2 for clean update
             if (not branchmerge and
                 (force or not wc.dirty(missing=True, branch=False))):
                 _checkcollision(repo, p2.manifest(), None)
             else:
                 _checkcollision(repo, wc.manifest(), actions)
 
         # Prompt and create actions. Most of this is in the resolve phase
         # already, but we can't handle .hgsubstate in filemerge or
         # subrepo.submerge yet so we have to keep prompting for it.
         for f, args, msg in sorted(actions['cd']):
             if f != '.hgsubstate':
                 continue
             if repo.ui.promptchoice(
                 _("local changed %s which remote deleted\n"
                   "use (c)hanged version or (d)elete?"
                   "$$ &Changed $$ &Delete") % f, 0):
                 actions['r'].append((f, None, "prompt delete"))
             elif f in p1:
                 actions['am'].append((f, None, "prompt keep"))
             else:
                 actions['a'].append((f, None, "prompt keep"))
 
         for f, args, msg in sorted(actions['dc']):
             if f != '.hgsubstate':
                 continue
             f1, f2, fa, move, anc = args
             flags = p2[f2].flags()
             if repo.ui.promptchoice(
                 _("remote changed %s which local deleted\n"
                   "use (c)hanged version or leave (d)eleted?"
                   "$$ &Changed $$ &Deleted") % f, 0) == 0:
                 actions['g'].append((f, (flags, False), "prompt recreating"))
 
         # divergent renames
         for f, fl in sorted(diverge.iteritems()):
             repo.ui.warn(_("note: possible conflict - %s was renamed "
                            "multiple times to:\n") % f)
             for nf in fl:
                 repo.ui.warn(" %s\n" % nf)
 
         # rename and delete
         for f, fl in sorted(renamedelete.iteritems()):
             repo.ui.warn(_("note: possible conflict - %s was deleted "
                            "and renamed to:\n") % f)
             for nf in fl:
                 repo.ui.warn(" %s\n" % nf)
 
         ### apply phase
         if not branchmerge: # just jump to the new rev
             fp1, fp2, xp1, xp2 = fp2, nullid, xp2, ''
         if not partial:
             repo.hook('preupdate', throw=True, parent1=xp1, parent2=xp2)
             # note that we're in the middle of an update
             repo.vfs.write('updatestate', p2.hex())
 
         stats = applyupdates(repo, actions, wc, p2, overwrite, labels=labels)
 
         if not partial:
             repo.dirstate.beginparentchange()
             repo.setparents(fp1, fp2)
             recordupdates(repo, actions, branchmerge)
             # update completed, clear state
             util.unlink(repo.join('updatestate'))
 
             if not branchmerge:
                 repo.dirstate.setbranch(p2.branch())
             repo.dirstate.endparentchange()
     finally:
         wlock.release()
 
     if not partial:
         repo.hook('update', parent1=xp1, parent2=xp2, error=stats[3])
     return stats
 
 def graft(repo, ctx, pctx, labels, keepparent=False):
     """Do a graft-like merge.
 
     This is a merge where the merge ancestor is chosen such that one
     or more changesets are grafted onto the current changeset. In
     addition to the merge, this fixes up the dirstate to include only
     a single parent (if keepparent is False) and tries to duplicate any
     renames/copies appropriately.
 
     ctx - changeset to rebase
     pctx - merge base, usually ctx.p1()
     labels - merge labels eg ['local', 'graft']
     keepparent - keep second parent if any
 
     """
     # If we're grafting a descendant onto an ancestor, be sure to pass
     # mergeancestor=True to update. This does two things: 1) allows the merge if
     # the destination is the same as the parent of the ctx (so we can use graft
     # to copy commits), and 2) informs update that the incoming changes are
     # newer than the destination so it doesn't prompt about "remote changed foo
     # which local deleted".
     mergeancestor = repo.changelog.isancestor(repo['.'].node(), ctx.node())
 
     stats = update(repo, ctx.node(), True, True, pctx.node(),
                    mergeancestor=mergeancestor, labels=labels)
 
     pother = nullid
     parents = ctx.parents()
     if keepparent and len(parents) == 2 and pctx in parents:
         parents.remove(pctx)
         pother = parents[0].node()
 
     repo.dirstate.beginparentchange()
     repo.setparents(repo['.'].node(), pother)
     repo.dirstate.write(repo.currenttransaction())
     # fix up dirstate for copies and renames
     copies.duplicatecopies(repo, ctx.rev(), pctx.rev())
     repo.dirstate.endparentchange()
     return stats

tests/test-merge1.t

@@ -1,318 +1,354 b''
   $ cat <<EOF > merge
   > import sys, os
   > 
   > try:
   >     import msvcrt
   >     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
   >     msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
   > except ImportError:
   >     pass
   > 
   > print "merging for", os.path.basename(sys.argv[1])
   > EOF
   $ HGMERGE="python ../merge"; export HGMERGE
 
   $ hg init t
   $ cd t
   $ echo This is file a1 > a
   $ hg add a
   $ hg commit -m "commit #0"
   $ echo This is file b1 > b
   $ hg add b
   $ hg commit -m "commit #1"
 
   $ hg update 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
 Test interrupted updates by exploiting our non-handling of directory collisions
 
   $ mkdir b
   $ hg up
   abort: *: '$TESTTMP/t/b' (glob)
   [255]
   $ hg ci
   abort: last update was interrupted
   (use 'hg update' to get a consistent checkout)
   [255]
   $ hg sum
   parent: 0:538afb845929 
    commit #0
   branch: default
   commit: (interrupted update)
   update: 1 new changesets (update)
   phases: 2 draft
   $ rmdir b
   $ hg up
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg sum
   parent: 1:b8bb4a988f25 tip
    commit #1
   branch: default
   commit: (clean)
   update: (current)
   phases: 2 draft
 
 Prepare a basic merge
 
   $ hg up 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo This is file c1 > c
   $ hg add c
   $ hg commit -m "commit #2"
   created new head
   $ echo This is file b1 > b
 no merges expected
   $ hg merge -P 1
   changeset:   1:b8bb4a988f25
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     commit #1
   
   $ hg merge 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg diff --nodates
   diff -r 49035e18a8e6 b
   --- /dev/null
   +++ b/b
   @@ -0,0 +1,1 @@
   +This is file b1
   $ hg status
   M b
   $ cd ..; rm -r t
 
   $ hg init t
   $ cd t
   $ echo This is file a1 > a
   $ hg add a
   $ hg commit -m "commit #0"
   $ echo This is file b1 > b
   $ hg add b
   $ hg commit -m "commit #1"
 
   $ hg update 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo This is file c1 > c
   $ hg add c
   $ hg commit -m "commit #2"
   created new head
   $ echo This is file b2 > b
 merge should fail
   $ hg merge 1
   b: untracked file differs
   abort: untracked files in working directory differ from files in requested revision
   [255]
 
 #if symlink
 symlinks to directories should be treated as regular files (issue5027)
   $ rm b
   $ ln -s 'This is file b2' b
   $ hg merge 1
   b: untracked file differs
   abort: untracked files in working directory differ from files in requested revision
   [255]
 symlinks shouldn't be followed
   $ rm b
   $ echo This is file b1 > .hg/b
   $ ln -s .hg/b b
   $ hg merge 1
   b: untracked file differs
   abort: untracked files in working directory differ from files in requested revision
   [255]
 
   $ rm b
   $ echo This is file b2 > b
 #endif
 
-merge of b expected
+bad config
+  $ hg merge 1 --config merge.checkunknown=x
+  abort: merge.checkunknown not valid ('x' is none of 'abort', 'ignore', 'warn')
+  [255]
+this merge should fail
+  $ hg merge 1 --config merge.checkunknown=abort
+  b: untracked file differs
+  abort: untracked files in working directory differ from files in requested revision
+  [255]
+
+this merge should warn
+  $ hg merge 1 --config merge.checkunknown=warn
+  b: replacing untracked file
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ cat b.orig
+  This is file b2
+  $ hg up --clean 2
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mv b.orig b
+
+this merge should silently ignore
+  $ cat b
+  This is file b2
+  $ hg merge 1 --config merge.checkunknown=ignore
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+
+  $ cat b.orig
+  This is file b2
+  $ hg up --clean 2
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mv b.orig b
+
+this merge of b should work
+  $ cat b
+  This is file b2
   $ hg merge -f 1
   merging b
   merging for b
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg diff --nodates
   diff -r 49035e18a8e6 b
   --- /dev/null
   +++ b/b
   @@ -0,0 +1,1 @@
   +This is file b2
   $ hg status
   M b
   $ cd ..; rm -r t
 
   $ hg init t
   $ cd t
   $ echo This is file a1 > a
   $ hg add a
   $ hg commit -m "commit #0"
   $ echo This is file b1 > b
   $ hg add b
   $ hg commit -m "commit #1"
   $ echo This is file b22 > b
   $ hg commit -m "commit #2"
   $ hg update 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo This is file c1 > c
   $ hg add c
   $ hg commit -m "commit #3"
   created new head
 
 Contents of b should be "this is file b1"
   $ cat b
   This is file b1
 
   $ echo This is file b22 > b
 merge fails
   $ hg merge 2
   abort: uncommitted changes
   (use 'hg status' to list changes)
   [255]
 merge expected!
   $ hg merge -f 2
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg diff --nodates
   diff -r 85de557015a8 b
   --- a/b
   +++ b/b
   @@ -1,1 +1,1 @@
   -This is file b1
   +This is file b22
   $ hg status
   M b
   $ cd ..; rm -r t
 
   $ hg init t
   $ cd t
   $ echo This is file a1 > a
   $ hg add a
   $ hg commit -m "commit #0"
   $ echo This is file b1 > b
   $ hg add b
   $ hg commit -m "commit #1"
   $ echo This is file b22 > b
   $ hg commit -m "commit #2"
   $ hg update 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo This is file c1 > c
   $ hg add c
   $ hg commit -m "commit #3"
   created new head
   $ echo This is file b33 > b
 merge of b should fail
   $ hg merge 2
   abort: uncommitted changes
   (use 'hg status' to list changes)
   [255]
 merge of b expected
   $ hg merge -f 2
   merging b
   merging for b
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg diff --nodates
   diff -r 85de557015a8 b
   --- a/b
   +++ b/b
   @@ -1,1 +1,1 @@
   -This is file b1
   +This is file b33
   $ hg status
   M b
 
 Test for issue2364
 
   $ hg up -qC .
   $ hg rm b
   $ hg ci -md
   $ hg revert -r -2 b
   $ hg up -q -- -2
 
 Test that updated files are treated as "modified", when
 'merge.update()' is aborted before 'merge.recordupdates()' (= parents
 aren't changed), even if none of mode, size and timestamp of them
 isn't changed on the filesystem (see also issue4583).
 
   $ cat > $TESTTMP/abort.py <<EOF
   > # emulate aborting before "recordupdates()". in this case, files
   > # are changed without updating dirstate
   > from mercurial import extensions, merge, error
   > def applyupdates(orig, *args, **kwargs):
   >     orig(*args, **kwargs)
   >     raise error.Abort('intentional aborting')
   > def extsetup(ui):
   >     extensions.wrapfunction(merge, "applyupdates", applyupdates)
   > EOF
 
   $ cat >> .hg/hgrc <<EOF
   > [fakedirstatewritetime]
   > # emulate invoking dirstate.write() via repo.status()
   > # at 2000-01-01 00:00
   > fakenow = 200001010000
   > EOF
 
 (file gotten from other revision)
 
   $ hg update -q -C 2
   $ echo 'THIS IS FILE B5' > b
   $ hg commit -m 'commit #5'
 
   $ hg update -q -C 3
   $ cat b
   This is file b1
   $ touch -t 200001010000 b
   $ hg debugrebuildstate
 
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
   > abort = $TESTTMP/abort.py
   > EOF
   $ hg merge 5
   abort: intentional aborting
   [255]
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > fakedirstatewritetime = !
   > abort = !
   > EOF
 
   $ cat b
   THIS IS FILE B5
   $ touch -t 200001010000 b
   $ hg status -A b
   M b
 
 (file merged from other revision)
 
   $ hg update -q -C 3
   $ echo 'this is file b6' > b
   $ hg commit -m 'commit #6'
   created new head
 
   $ cat b
   this is file b6
   $ touch -t 200001010000 b
   $ hg debugrebuildstate
 
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
   > abort = $TESTTMP/abort.py
   > EOF
   $ hg merge --tool internal:other 5
   abort: intentional aborting
   [255]
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > fakedirstatewritetime = !
   > abort = !
   > EOF
 
   $ cat b
   THIS IS FILE B5
   $ touch -t 200001010000 b
   $ hg status -A b
   M b
 
   $ cd ..