fix: allow tools to use :linerange, but also run if a file is unchanged

The definition of "unchanged" here is subtle, because pure deletion diff hunks
are ignored. That means this is different from using the --whole flag. This
change allows you to configure, for example, a code formatter that:
 1. Formats specific line ranges if specified via flags
 2. Does not format the entire file when there are no line ranges provided
 3. Performs some other kind of formatting regardless of provided line ranges

This sounds a little far fetched, but it is meant to address a specific corner
case encountered in Google's use of the fix extension. The default behavior is
kept because it exists to prevent mistakes that could erase uncommitted
changes.

Differential Revision: https://phab.mercurial-scm.org/D6723

hgext/fix.py

@@ -1,765 +1,777 b''
 # fix - rewrite file content in changesets and working copy
 #
 # Copyright 2018 Google LLC.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 """rewrite file content in changesets or working copy (EXPERIMENTAL)
 
 Provides a command that runs configured tools on the contents of modified files,
 writing back any fixes to the working copy or replacing changesets.
 
 Here is an example configuration that causes :hg:`fix` to apply automatic
 formatting fixes to modified lines in C++ code::
 
   [fix]
   clang-format:command=clang-format --assume-filename={rootpath}
   clang-format:linerange=--lines={first}:{last}
   clang-format:pattern=set:**.cpp or **.hpp
 
 The :command suboption forms the first part of the shell command that will be
 used to fix a file. The content of the file is passed on standard input, and the
 fixed file content is expected on standard output. Any output on standard error
 will be displayed as a warning. If the exit status is not zero, the file will
 not be affected. A placeholder warning is displayed if there is a non-zero exit
 status but no standard error output. Some values may be substituted into the
 command::
 
   {rootpath}  The path of the file being fixed, relative to the repo root
   {basename}  The name of the file being fixed, without the directory path
 
 If the :linerange suboption is set, the tool will only be run if there are
 changed lines in a file. The value of this suboption is appended to the shell
 command once for every range of changed lines in the file. Some values may be
 substituted into the command::
 
   {first}   The 1-based line number of the first line in the modified range
   {last}    The 1-based line number of the last line in the modified range
 
+Deleted sections of a file will be ignored by :linerange, because there is no
+corresponding line range in the version being fixed.
+
+By default, tools that set :linerange will only be executed if there is at least
+one changed line range. This is meant to prevent accidents like running a code
+formatter in such a way that it unexpectedly reformats the whole file. If such a
+tool needs to operate on unchanged files, it should set the :skipclean suboption
+to false.
+
 The :pattern suboption determines which files will be passed through each
 configured tool. See :hg:`help patterns` for possible values. If there are file
 arguments to :hg:`fix`, the intersection of these patterns is used.
 
 There is also a configurable limit for the maximum size of file that will be
 processed by :hg:`fix`::
 
   [fix]
   maxfilesize = 2MB
 
 Normally, execution of configured tools will continue after a failure (indicated
 by a non-zero exit status). It can also be configured to abort after the first
 such failure, so that no files will be affected if any tool fails. This abort
 will also cause :hg:`fix` to exit with a non-zero status::
 
   [fix]
   failure = abort
 
 When multiple tools are configured to affect a file, they execute in an order
 defined by the :priority suboption. The priority suboption has a default value
 of zero for each tool. Tools are executed in order of descending priority. The
 execution order of tools with equal priority is unspecified. For example, you
 could use the 'sort' and 'head' utilities to keep only the 10 smallest numbers
 in a text file by ensuring that 'sort' runs before 'head'::
 
   [fix]
   sort:command = sort -n
   head:command = head -n 10
   sort:pattern = numbers.txt
   head:pattern = numbers.txt
   sort:priority = 2
   head:priority = 1
 
 To account for changes made by each tool, the line numbers used for incremental
 formatting are recomputed before executing the next tool. So, each tool may see
 different values for the arguments added by the :linerange suboption.
 
 Each fixer tool is allowed to return some metadata in addition to the fixed file
 content. The metadata must be placed before the file content on stdout,
 separated from the file content by a zero byte. The metadata is parsed as a JSON
 value (so, it should be UTF-8 encoded and contain no zero bytes). A fixer tool
 is expected to produce this metadata encoding if and only if the :metadata
 suboption is true::
 
   [fix]
   tool:command = tool --prepend-json-metadata
   tool:metadata = true
 
 The metadata values are passed to hooks, which can be used to print summaries or
 perform other post-fixing work. The supported hooks are::
 
   "postfixfile"
     Run once for each file in each revision where any fixer tools made changes
     to the file content. Provides "$HG_REV" and "$HG_PATH" to identify the file,
     and "$HG_METADATA" with a map of fixer names to metadata values from fixer
     tools that affected the file. Fixer tools that didn't affect the file have a
     valueof None. Only fixer tools that executed are present in the metadata.
 
   "postfix"
     Run once after all files and revisions have been handled. Provides
     "$HG_REPLACEMENTS" with information about what revisions were created and
     made obsolete. Provides a boolean "$HG_WDIRWRITTEN" to indicate whether any
     files in the working copy were updated. Provides a list "$HG_METADATA"
     mapping fixer tool names to lists of metadata values returned from
     executions that modified a file. This aggregates the same metadata
     previously passed to the "postfixfile" hook.
 
 Fixer tools are run the in repository's root directory. This allows them to read
 configuration files from the working copy, or even write to the working copy.
 The working copy is not updated to match the revision being fixed. In fact,
 several revisions may be fixed in parallel. Writes to the working copy are not
 amended into the revision being fixed; fixer tools should always write fixed
 file content back to stdout as documented above.
 """
 
 from __future__ import absolute_import
 
 import collections
 import itertools
 import json
 import os
 import re
 import subprocess
 
 from mercurial.i18n import _
 from mercurial.node import nullrev
 from mercurial.node import wdirrev
 
 from mercurial.utils import (
     procutil,
+    stringutil,
 )
 
 from mercurial import (
     cmdutil,
     context,
     copies,
     error,
     mdiff,
     merge,
     obsolete,
     pycompat,
     registrar,
     scmutil,
     util,
     worker,
 )
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 # Register the suboptions allowed for each configured fixer, and default values.
 FIXER_ATTRS = {
     'command': None,
     'linerange': None,
     'pattern': None,
     'priority': 0,
     'metadata': False,
+    'skipclean': 'true',
 }
 
 for key, default in FIXER_ATTRS.items():
     configitem('fix', '.*(:%s)?' % key, default=default, generic=True)
 
 # A good default size allows most source code files to be fixed, but avoids
 # letting fixer tools choke on huge inputs, which could be surprising to the
 # user.
 configitem('fix', 'maxfilesize', default='2MB')
 
 # Allow fix commands to exit non-zero if an executed fixer tool exits non-zero.
 # This helps users do shell scripts that stop when a fixer tool signals a
 # problem.
 configitem('fix', 'failure', default='continue')
 
 def checktoolfailureaction(ui, message, hint=None):
     """Abort with 'message' if fix.failure=abort"""
     action = ui.config('fix', 'failure')
     if action not in ('continue', 'abort'):
         raise error.Abort(_('unknown fix.failure action: %s') % (action,),
                           hint=_('use "continue" or "abort"'))
     if action == 'abort':
         raise error.Abort(message, hint=hint)
 
 allopt = ('', 'all', False, _('fix all non-public non-obsolete revisions'))
 baseopt = ('', 'base', [], _('revisions to diff against (overrides automatic '
                              'selection, and applies to every revision being '
                              'fixed)'), _('REV'))
 revopt = ('r', 'rev', [], _('revisions to fix'), _('REV'))
 wdiropt = ('w', 'working-dir', False, _('fix the working directory'))
 wholeopt = ('', 'whole', False, _('always fix every line of a file'))
 usage = _('[OPTION]... [FILE]...')
 
 @command('fix', [allopt, baseopt, revopt, wdiropt, wholeopt], usage,
         helpcategory=command.CATEGORY_FILE_CONTENTS)
 def fix(ui, repo, *pats, **opts):
     """rewrite file content in changesets or working directory
 
     Runs any configured tools to fix the content of files. Only affects files
     with changes, unless file arguments are provided. Only affects changed lines
     of files, unless the --whole flag is used. Some tools may always affect the
     whole file regardless of --whole.
 
     If revisions are specified with --rev, those revisions will be checked, and
     they may be replaced with new revisions that have fixed file content.  It is
     desirable to specify all descendants of each specified revision, so that the
     fixes propagate to the descendants. If all descendants are fixed at the same
     time, no merging, rebasing, or evolution will be required.
 
     If --working-dir is used, files with uncommitted changes in the working copy
     will be fixed. If the checked-out revision is also fixed, the working
     directory will update to the replacement revision.
 
     When determining what lines of each file to fix at each revision, the whole
     set of revisions being fixed is considered, so that fixes to earlier
     revisions are not forgotten in later ones. The --base flag can be used to
     override this default behavior, though it is not usually desirable to do so.
     """
     opts = pycompat.byteskwargs(opts)
     if opts['all']:
         if opts['rev']:
             raise error.Abort(_('cannot specify both "--rev" and "--all"'))
         opts['rev'] = ['not public() and not obsolete()']
         opts['working_dir'] = True
     with repo.wlock(), repo.lock(), repo.transaction('fix'):
         revstofix = getrevstofix(ui, repo, opts)
         basectxs = getbasectxs(repo, opts, revstofix)
         workqueue, numitems = getworkqueue(ui, repo, pats, opts, revstofix,
                                            basectxs)
         fixers = getfixers(ui)
 
         # There are no data dependencies between the workers fixing each file
         # revision, so we can use all available parallelism.
         def getfixes(items):
             for rev, path in items:
                 ctx = repo[rev]
                 olddata = ctx[path].data()
                 metadata, newdata = fixfile(ui, repo, opts, fixers, ctx, path,
                                             basectxs[rev])
                 # Don't waste memory/time passing unchanged content back, but
                 # produce one result per item either way.
                 yield (rev, path, metadata,
                        newdata if newdata != olddata else None)
         results = worker.worker(ui, 1.0, getfixes, tuple(), workqueue,
                                 threadsafe=False)
 
         # We have to hold on to the data for each successor revision in memory
         # until all its parents are committed. We ensure this by committing and
         # freeing memory for the revisions in some topological order. This
         # leaves a little bit of memory efficiency on the table, but also makes
         # the tests deterministic. It might also be considered a feature since
         # it makes the results more easily reproducible.
         filedata = collections.defaultdict(dict)
         aggregatemetadata = collections.defaultdict(list)
         replacements = {}
         wdirwritten = False
         commitorder = sorted(revstofix, reverse=True)
         with ui.makeprogress(topic=_('fixing'), unit=_('files'),
                              total=sum(numitems.values())) as progress:
             for rev, path, filerevmetadata, newdata in results:
                 progress.increment(item=path)
                 for fixername, fixermetadata in filerevmetadata.items():
                     aggregatemetadata[fixername].append(fixermetadata)
                 if newdata is not None:
                     filedata[rev][path] = newdata
                     hookargs = {
                       'rev': rev,
                       'path': path,
                       'metadata': filerevmetadata,
                     }
                     repo.hook('postfixfile', throw=False,
                               **pycompat.strkwargs(hookargs))
                 numitems[rev] -= 1
                 # Apply the fixes for this and any other revisions that are
                 # ready and sitting at the front of the queue. Using a loop here
                 # prevents the queue from being blocked by the first revision to
                 # be ready out of order.
                 while commitorder and not numitems[commitorder[-1]]:
                     rev = commitorder.pop()
                     ctx = repo[rev]
                     if rev == wdirrev:
                         writeworkingdir(repo, ctx, filedata[rev], replacements)
                         wdirwritten = bool(filedata[rev])
                     else:
                         replacerev(ui, repo, ctx, filedata[rev], replacements)
                     del filedata[rev]
 
         cleanup(repo, replacements, wdirwritten)
         hookargs = {
             'replacements': replacements,
             'wdirwritten': wdirwritten,
             'metadata': aggregatemetadata,
         }
         repo.hook('postfix', throw=True, **pycompat.strkwargs(hookargs))
 
 def cleanup(repo, replacements, wdirwritten):
     """Calls scmutil.cleanupnodes() with the given replacements.
 
     "replacements" is a dict from nodeid to nodeid, with one key and one value
     for every revision that was affected by fixing. This is slightly different
     from cleanupnodes().
 
     "wdirwritten" is a bool which tells whether the working copy was affected by
     fixing, since it has no entry in "replacements".
 
     Useful as a hook point for extending "hg fix" with output summarizing the
     effects of the command, though we choose not to output anything here.
     """
     replacements = {prec: [succ] for prec, succ in replacements.iteritems()}
     scmutil.cleanupnodes(repo, replacements, 'fix', fixphase=True)
 
 def getworkqueue(ui, repo, pats, opts, revstofix, basectxs):
     """"Constructs the list of files to be fixed at specific revisions
 
     It is up to the caller how to consume the work items, and the only
     dependence between them is that replacement revisions must be committed in
     topological order. Each work item represents a file in the working copy or
     in some revision that should be fixed and written back to the working copy
     or into a replacement revision.
 
     Work items for the same revision are grouped together, so that a worker
     pool starting with the first N items in parallel is likely to finish the
     first revision's work before other revisions. This can allow us to write
     the result to disk and reduce memory footprint. At time of writing, the
     partition strategy in worker.py seems favorable to this. We also sort the
     items by ascending revision number to match the order in which we commit
     the fixes later.
     """
     workqueue = []
     numitems = collections.defaultdict(int)
     maxfilesize = ui.configbytes('fix', 'maxfilesize')
     for rev in sorted(revstofix):
         fixctx = repo[rev]
         match = scmutil.match(fixctx, pats, opts)
         for path in sorted(pathstofix(
                         ui, repo, pats, opts, match, basectxs[rev], fixctx)):
             fctx = fixctx[path]
             if fctx.islink():
                 continue
             if fctx.size() > maxfilesize:
                 ui.warn(_('ignoring file larger than %s: %s\n') %
                         (util.bytecount(maxfilesize), path))
                 continue
             workqueue.append((rev, path))
             numitems[rev] += 1
     return workqueue, numitems
 
 def getrevstofix(ui, repo, opts):
     """Returns the set of revision numbers that should be fixed"""
     revs = set(scmutil.revrange(repo, opts['rev']))
     for rev in revs:
         checkfixablectx(ui, repo, repo[rev])
     if revs:
         cmdutil.checkunfinished(repo)
         checknodescendants(repo, revs)
     if opts.get('working_dir'):
         revs.add(wdirrev)
         if list(merge.mergestate.read(repo).unresolved()):
             raise error.Abort('unresolved conflicts', hint="use 'hg resolve'")
     if not revs:
         raise error.Abort(
             'no changesets specified', hint='use --rev or --working-dir')
     return revs
 
 def checknodescendants(repo, revs):
     if (not obsolete.isenabled(repo, obsolete.allowunstableopt) and
         repo.revs('(%ld::) - (%ld)', revs, revs)):
         raise error.Abort(_('can only fix a changeset together '
                             'with all its descendants'))
 
 def checkfixablectx(ui, repo, ctx):
     """Aborts if the revision shouldn't be replaced with a fixed one."""
     if not ctx.mutable():
         raise error.Abort('can\'t fix immutable changeset %s' %
                           (scmutil.formatchangeid(ctx),))
     if ctx.obsolete():
         # It would be better to actually check if the revision has a successor.
         allowdivergence = ui.configbool('experimental',
                                         'evolution.allowdivergence')
         if not allowdivergence:
             raise error.Abort('fixing obsolete revision could cause divergence')
 
 def pathstofix(ui, repo, pats, opts, match, basectxs, fixctx):
     """Returns the set of files that should be fixed in a context
 
     The result depends on the base contexts; we include any file that has
     changed relative to any of the base contexts. Base contexts should be
     ancestors of the context being fixed.
     """
     files = set()
     for basectx in basectxs:
         stat = basectx.status(fixctx, match=match, listclean=bool(pats),
                               listunknown=bool(pats))
         files.update(
             set(itertools.chain(stat.added, stat.modified, stat.clean,
                                 stat.unknown)))
     return files
 
 def lineranges(opts, path, basectxs, fixctx, content2):
     """Returns the set of line ranges that should be fixed in a file
 
     Of the form [(10, 20), (30, 40)].
 
     This depends on the given base contexts; we must consider lines that have
     changed versus any of the base contexts, and whether the file has been
     renamed versus any of them.
 
     Another way to understand this is that we exclude line ranges that are
     common to the file in all base contexts.
     """
     if opts.get('whole'):
         # Return a range containing all lines. Rely on the diff implementation's
         # idea of how many lines are in the file, instead of reimplementing it.
         return difflineranges('', content2)
 
     rangeslist = []
     for basectx in basectxs:
         basepath = copies.pathcopies(basectx, fixctx).get(path, path)
         if basepath in basectx:
             content1 = basectx[basepath].data()
         else:
             content1 = ''
         rangeslist.extend(difflineranges(content1, content2))
     return unionranges(rangeslist)
 
 def unionranges(rangeslist):
     """Return the union of some closed intervals
 
     >>> unionranges([])
     []
     >>> unionranges([(1, 100)])
     [(1, 100)]
     >>> unionranges([(1, 100), (1, 100)])
     [(1, 100)]
     >>> unionranges([(1, 100), (2, 100)])
     [(1, 100)]
     >>> unionranges([(1, 99), (1, 100)])
     [(1, 100)]
     >>> unionranges([(1, 100), (40, 60)])
     [(1, 100)]
     >>> unionranges([(1, 49), (50, 100)])
     [(1, 100)]
     >>> unionranges([(1, 48), (50, 100)])
     [(1, 48), (50, 100)]
     >>> unionranges([(1, 2), (3, 4), (5, 6)])
     [(1, 6)]
     """
     rangeslist = sorted(set(rangeslist))
     unioned = []
     if rangeslist:
         unioned, rangeslist = [rangeslist[0]], rangeslist[1:]
     for a, b in rangeslist:
         c, d = unioned[-1]
         if a > d + 1:
             unioned.append((a, b))
         else:
             unioned[-1] = (c, max(b, d))
     return unioned
 
 def difflineranges(content1, content2):
     """Return list of line number ranges in content2 that differ from content1.
 
     Line numbers are 1-based. The numbers are the first and last line contained
     in the range. Single-line ranges have the same line number for the first and
     last line. Excludes any empty ranges that result from lines that are only
     present in content1. Relies on mdiff's idea of where the line endings are in
     the string.
 
     >>> from mercurial import pycompat
     >>> lines = lambda s: b'\\n'.join([c for c in pycompat.iterbytestr(s)])
     >>> difflineranges2 = lambda a, b: difflineranges(lines(a), lines(b))
     >>> difflineranges2(b'', b'')
     []
     >>> difflineranges2(b'a', b'')
     []
     >>> difflineranges2(b'', b'A')
     [(1, 1)]
     >>> difflineranges2(b'a', b'a')
     []
     >>> difflineranges2(b'a', b'A')
     [(1, 1)]
     >>> difflineranges2(b'ab', b'')
     []
     >>> difflineranges2(b'', b'AB')
     [(1, 2)]
     >>> difflineranges2(b'abc', b'ac')
     []
     >>> difflineranges2(b'ab', b'aCb')
     [(2, 2)]
     >>> difflineranges2(b'abc', b'aBc')
     [(2, 2)]
     >>> difflineranges2(b'ab', b'AB')
     [(1, 2)]
     >>> difflineranges2(b'abcde', b'aBcDe')
     [(2, 2), (4, 4)]
     >>> difflineranges2(b'abcde', b'aBCDe')
     [(2, 4)]
     """
     ranges = []
     for lines, kind in mdiff.allblocks(content1, content2):
         firstline, lastline = lines[2:4]
         if kind == '!' and firstline != lastline:
             ranges.append((firstline + 1, lastline))
     return ranges
 
 def getbasectxs(repo, opts, revstofix):
     """Returns a map of the base contexts for each revision
 
     The base contexts determine which lines are considered modified when we
     attempt to fix just the modified lines in a file. It also determines which
     files we attempt to fix, so it is important to compute this even when
     --whole is used.
     """
     # The --base flag overrides the usual logic, and we give every revision
     # exactly the set of baserevs that the user specified.
     if opts.get('base'):
         baserevs = set(scmutil.revrange(repo, opts.get('base')))
         if not baserevs:
             baserevs = {nullrev}
         basectxs = {repo[rev] for rev in baserevs}
         return {rev: basectxs for rev in revstofix}
 
     # Proceed in topological order so that we can easily determine each
     # revision's baserevs by looking at its parents and their baserevs.
     basectxs = collections.defaultdict(set)
     for rev in sorted(revstofix):
         ctx = repo[rev]
         for pctx in ctx.parents():
             if pctx.rev() in basectxs:
                 basectxs[rev].update(basectxs[pctx.rev()])
             else:
                 basectxs[rev].add(pctx)
     return basectxs
 
 def fixfile(ui, repo, opts, fixers, fixctx, path, basectxs):
     """Run any configured fixers that should affect the file in this context
 
     Returns the file content that results from applying the fixers in some order
     starting with the file's content in the fixctx. Fixers that support line
     ranges will affect lines that have changed relative to any of the basectxs
     (i.e. they will only avoid lines that are common to all basectxs).
 
     A fixer tool's stdout will become the file's new content if and only if it
     exits with code zero. The fixer tool's working directory is the repository's
     root.
     """
     metadata = {}
     newdata = fixctx[path].data()
     for fixername, fixer in fixers.iteritems():
         if fixer.affects(opts, fixctx, path):
             rangesfn = lambda: lineranges(opts, path, basectxs, fixctx, newdata)
             command = fixer.command(ui, path, rangesfn)
             if command is None:
                 continue
             ui.debug('subprocess: %s\n' % (command,))
             proc = subprocess.Popen(
                 procutil.tonativestr(command),
                 shell=True,
                 cwd=repo.root,
                 stdin=subprocess.PIPE,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE)
             stdout, stderr = proc.communicate(newdata)
             if stderr:
                 showstderr(ui, fixctx.rev(), fixername, stderr)
             newerdata = stdout
             if fixer.shouldoutputmetadata():
                 try:
                     metadatajson, newerdata = stdout.split('\0', 1)
                     metadata[fixername] = json.loads(metadatajson)
                 except ValueError:
                     ui.warn(_('ignored invalid output from fixer tool: %s\n') %
                             (fixername,))
                     continue
             else:
                 metadata[fixername] = None
             if proc.returncode == 0:
                 newdata = newerdata
             else:
                 if not stderr:
                     message = _('exited with status %d\n') % (proc.returncode,)
                     showstderr(ui, fixctx.rev(), fixername, message)
                 checktoolfailureaction(
                     ui, _('no fixes will be applied'),
                     hint=_('use --config fix.failure=continue to apply any '
                            'successful fixes anyway'))
     return metadata, newdata
 
 def showstderr(ui, rev, fixername, stderr):
     """Writes the lines of the stderr string as warnings on the ui
 
     Uses the revision number and fixername to give more context to each line of
     the error message. Doesn't include file names, since those take up a lot of
     space and would tend to be included in the error message if they were
     relevant.
     """
     for line in re.split('[\r\n]+', stderr):
         if line:
             ui.warn(('['))
             if rev is None:
                 ui.warn(_('wdir'), label='evolve.rev')
             else:
                 ui.warn((str(rev)), label='evolve.rev')
             ui.warn(('] %s: %s\n') % (fixername, line))
 
 def writeworkingdir(repo, ctx, filedata, replacements):
     """Write new content to the working copy and check out the new p1 if any
 
     We check out a new revision if and only if we fixed something in both the
     working directory and its parent revision. This avoids the need for a full
     update/merge, and means that the working directory simply isn't affected
     unless the --working-dir flag is given.
 
     Directly updates the dirstate for the affected files.
     """
     for path, data in filedata.iteritems():
         fctx = ctx[path]
         fctx.write(data, fctx.flags())
         if repo.dirstate[path] == 'n':
             repo.dirstate.normallookup(path)
 
     oldparentnodes = repo.dirstate.parents()
     newparentnodes = [replacements.get(n, n) for n in oldparentnodes]
     if newparentnodes != oldparentnodes:
         repo.setparents(*newparentnodes)
 
 def replacerev(ui, repo, ctx, filedata, replacements):
     """Commit a new revision like the given one, but with file content changes
 
     "ctx" is the original revision to be replaced by a modified one.
 
     "filedata" is a dict that maps paths to their new file content. All other
     paths will be recreated from the original revision without changes.
     "filedata" may contain paths that didn't exist in the original revision;
     they will be added.
 
     "replacements" is a dict that maps a single node to a single node, and it is
     updated to indicate the original revision is replaced by the newly created
     one. No entry is added if the replacement's node already exists.
 
     The new revision has the same parents as the old one, unless those parents
     have already been replaced, in which case those replacements are the parents
     of this new revision. Thus, if revisions are replaced in topological order,
     there is no need to rebase them into the original topology later.
     """
 
     p1rev, p2rev = repo.changelog.parentrevs(ctx.rev())
     p1ctx, p2ctx = repo[p1rev], repo[p2rev]
     newp1node = replacements.get(p1ctx.node(), p1ctx.node())
     newp2node = replacements.get(p2ctx.node(), p2ctx.node())
 
     # We don't want to create a revision that has no changes from the original,
     # but we should if the original revision's parent has been replaced.
     # Otherwise, we would produce an orphan that needs no actual human
     # intervention to evolve. We can't rely on commit() to avoid creating the
     # un-needed revision because the extra field added below produces a new hash
     # regardless of file content changes.
     if (not filedata and
         p1ctx.node() not in replacements and
         p2ctx.node() not in replacements):
         return
 
     def filectxfn(repo, memctx, path):
         if path not in ctx:
             return None
         fctx = ctx[path]
         copysource = fctx.copysource()
         return context.memfilectx(
             repo,
             memctx,
             path=fctx.path(),
             data=filedata.get(path, fctx.data()),
             islink=fctx.islink(),
             isexec=fctx.isexec(),
             copysource=copysource)
 
     extra = ctx.extra().copy()
     extra['fix_source'] = ctx.hex()
 
     memctx = context.memctx(
         repo,
         parents=(newp1node, newp2node),
         text=ctx.description(),
         files=set(ctx.files()) | set(filedata.keys()),
         filectxfn=filectxfn,
         user=ctx.user(),
         date=ctx.date(),
         extra=extra,
         branch=ctx.branch(),
         editor=None)
     sucnode = memctx.commit()
     prenode = ctx.node()
     if prenode == sucnode:
         ui.debug('node %s already existed\n' % (ctx.hex()))
     else:
         replacements[ctx.node()] = sucnode
 
 def getfixers(ui):
     """Returns a map of configured fixer tools indexed by their names
 
     Each value is a Fixer object with methods that implement the behavior of the
     fixer's config suboptions. Does not validate the config values.
     """
     fixers = {}
     for name in fixernames(ui):
         fixers[name] = Fixer()
         attrs = ui.configsuboptions('fix', name)[1]
         for key, default in FIXER_ATTRS.items():
             setattr(fixers[name], pycompat.sysstr('_' + key),
                     attrs.get(key, default))
         fixers[name]._priority = int(fixers[name]._priority)
+        fixers[name]._skipclean = stringutil.parsebool(fixers[name]._skipclean)
         # Don't use a fixer if it has no pattern configured. It would be
         # dangerous to let it affect all files. It would be pointless to let it
         # affect no files. There is no reasonable subset of files to use as the
         # default.
         if fixers[name]._pattern is None:
             ui.warn(
                 _('fixer tool has no pattern configuration: %s\n') % (name,))
             del fixers[name]
     return collections.OrderedDict(
         sorted(fixers.items(), key=lambda item: item[1]._priority,
                reverse=True))
 
 def fixernames(ui):
     """Returns the names of [fix] config options that have suboptions"""
     names = set()
     for k, v in ui.configitems('fix'):
         if ':' in k:
             names.add(k.split(':', 1)[0])
     return names
 
 class Fixer(object):
     """Wraps the raw config values for a fixer with methods"""
 
     def affects(self, opts, fixctx, path):
         """Should this fixer run on the file at the given path and context?"""
         return (self._pattern is not None and
                 scmutil.match(fixctx, [self._pattern], opts)(path))
 
     def shouldoutputmetadata(self):
         """Should the stdout of this fixer start with JSON and a null byte?"""
         return self._metadata
 
     def command(self, ui, path, rangesfn):
         """A shell command to use to invoke this fixer on the given file/lines
 
         May return None if there is no appropriate command to run for the given
         parameters.
         """
         expand = cmdutil.rendercommandtemplate
         parts = [expand(ui, self._command,
                         {'rootpath': path, 'basename': os.path.basename(path)})]
         if self._linerange:
             ranges = rangesfn()
-            if not ranges:
+            if self._skipclean and not ranges:
                 # No line ranges to fix, so don't run the fixer.
                 return None
             for first, last in ranges:
                 parts.append(expand(ui, self._linerange,
                                     {'first': first, 'last': last}))
         return ' '.join(parts)

tests/test-fix.t

@@ -1,1358 +1,1398 b''
 A script that implements uppercasing of specific lines in a file. This
 approximates the behavior of code formatters well enough for our tests.
 
   $ UPPERCASEPY="$TESTTMP/uppercase.py"
   $ cat > $UPPERCASEPY <<EOF
   > import sys
   > from mercurial.utils.procutil import setbinary
   > setbinary(sys.stdin)
   > setbinary(sys.stdout)
   > lines = set()
   > for arg in sys.argv[1:]:
   >   if arg == 'all':
   >     sys.stdout.write(sys.stdin.read().upper())
   >     sys.exit(0)
   >   else:
   >     first, last = arg.split('-')
   >     lines.update(range(int(first), int(last) + 1))
   > for i, line in enumerate(sys.stdin.readlines()):
   >   if i + 1 in lines:
   >     sys.stdout.write(line.upper())
   >   else:
   >     sys.stdout.write(line)
   > EOF
   $ TESTLINES="foo\nbar\nbaz\nqux\n"
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY
   foo
   bar
   baz
   qux
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY all
   FOO
   BAR
   BAZ
   QUX
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY 1-1
   FOO
   bar
   baz
   qux
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY 1-2
   FOO
   BAR
   baz
   qux
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY 2-3
   foo
   BAR
   BAZ
   qux
   $ printf $TESTLINES | "$PYTHON" $UPPERCASEPY 2-2 4-4
   foo
   BAR
   baz
   QUX
 
 Set up the config with two simple fixers: one that fixes specific line ranges,
 and one that always fixes the whole file. They both "fix" files by converting
 letters to uppercase. They use different file extensions, so each test case can
 choose which behavior to use by naming files.
 
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > fix =
   > [experimental]
   > evolution.createmarkers=True
   > evolution.allowunstable=True
   > [fix]
   > uppercase-whole-file:command="$PYTHON" $UPPERCASEPY all
   > uppercase-whole-file:pattern=set:**.whole
   > uppercase-changed-lines:command="$PYTHON" $UPPERCASEPY
   > uppercase-changed-lines:linerange={first}-{last}
   > uppercase-changed-lines:pattern=set:**.changed
   > EOF
 
 Help text for fix.
 
   $ hg help fix
   hg fix [OPTION]... [FILE]...
   
   rewrite file content in changesets or working directory
   
       Runs any configured tools to fix the content of files. Only affects files
       with changes, unless file arguments are provided. Only affects changed
       lines of files, unless the --whole flag is used. Some tools may always
       affect the whole file regardless of --whole.
   
       If revisions are specified with --rev, those revisions will be checked,
       and they may be replaced with new revisions that have fixed file content.
       It is desirable to specify all descendants of each specified revision, so
       that the fixes propagate to the descendants. If all descendants are fixed
       at the same time, no merging, rebasing, or evolution will be required.
   
       If --working-dir is used, files with uncommitted changes in the working
       copy will be fixed. If the checked-out revision is also fixed, the working
       directory will update to the replacement revision.
   
       When determining what lines of each file to fix at each revision, the
       whole set of revisions being fixed is considered, so that fixes to earlier
       revisions are not forgotten in later ones. The --base flag can be used to
       override this default behavior, though it is not usually desirable to do
       so.
   
   (use 'hg help -e fix' to show help for the fix extension)
   
   options ([+] can be repeated):
   
       --all          fix all non-public non-obsolete revisions
       --base REV [+] revisions to diff against (overrides automatic selection,
                      and applies to every revision being fixed)
    -r --rev REV [+]  revisions to fix
    -w --working-dir  fix the working directory
       --whole        always fix every line of a file
   
   (some details hidden, use --verbose to show complete help)
 
   $ hg help -e fix
   fix extension - rewrite file content in changesets or working copy
   (EXPERIMENTAL)
   
   Provides a command that runs configured tools on the contents of modified
   files, writing back any fixes to the working copy or replacing changesets.
   
   Here is an example configuration that causes 'hg fix' to apply automatic
   formatting fixes to modified lines in C++ code:
   
     [fix]
     clang-format:command=clang-format --assume-filename={rootpath}
     clang-format:linerange=--lines={first}:{last}
     clang-format:pattern=set:**.cpp or **.hpp
   
   The :command suboption forms the first part of the shell command that will be
   used to fix a file. The content of the file is passed on standard input, and
   the fixed file content is expected on standard output. Any output on standard
   error will be displayed as a warning. If the exit status is not zero, the file
   will not be affected. A placeholder warning is displayed if there is a non-
   zero exit status but no standard error output. Some values may be substituted
   into the command:
   
     {rootpath}  The path of the file being fixed, relative to the repo root
     {basename}  The name of the file being fixed, without the directory path
   
   If the :linerange suboption is set, the tool will only be run if there are
   changed lines in a file. The value of this suboption is appended to the shell
   command once for every range of changed lines in the file. Some values may be
   substituted into the command:
   
     {first}   The 1-based line number of the first line in the modified range
     {last}    The 1-based line number of the last line in the modified range
   
+  Deleted sections of a file will be ignored by :linerange, because there is no
+  corresponding line range in the version being fixed.
+  
+  By default, tools that set :linerange will only be executed if there is at
+  least one changed line range. This is meant to prevent accidents like running
+  a code formatter in such a way that it unexpectedly reformats the whole file.
+  If such a tool needs to operate on unchanged files, it should set the
+  :skipclean suboption to false.
+  
   The :pattern suboption determines which files will be passed through each
   configured tool. See 'hg help patterns' for possible values. If there are file
   arguments to 'hg fix', the intersection of these patterns is used.
   
   There is also a configurable limit for the maximum size of file that will be
   processed by 'hg fix':
   
     [fix]
     maxfilesize = 2MB
   
   Normally, execution of configured tools will continue after a failure
   (indicated by a non-zero exit status). It can also be configured to abort
   after the first such failure, so that no files will be affected if any tool
   fails. This abort will also cause 'hg fix' to exit with a non-zero status:
   
     [fix]
     failure = abort
   
   When multiple tools are configured to affect a file, they execute in an order
   defined by the :priority suboption. The priority suboption has a default value
   of zero for each tool. Tools are executed in order of descending priority. The
   execution order of tools with equal priority is unspecified. For example, you
   could use the 'sort' and 'head' utilities to keep only the 10 smallest numbers
   in a text file by ensuring that 'sort' runs before 'head':
   
     [fix]
     sort:command = sort -n
     head:command = head -n 10
     sort:pattern = numbers.txt
     head:pattern = numbers.txt
     sort:priority = 2
     head:priority = 1
   
   To account for changes made by each tool, the line numbers used for
   incremental formatting are recomputed before executing the next tool. So, each
   tool may see different values for the arguments added by the :linerange
   suboption.
   
   Each fixer tool is allowed to return some metadata in addition to the fixed
   file content. The metadata must be placed before the file content on stdout,
   separated from the file content by a zero byte. The metadata is parsed as a
   JSON value (so, it should be UTF-8 encoded and contain no zero bytes). A fixer
   tool is expected to produce this metadata encoding if and only if the
   :metadata suboption is true:
   
     [fix]
     tool:command = tool --prepend-json-metadata
     tool:metadata = true
   
   The metadata values are passed to hooks, which can be used to print summaries
   or perform other post-fixing work. The supported hooks are:
   
     "postfixfile"
       Run once for each file in each revision where any fixer tools made changes
       to the file content. Provides "$HG_REV" and "$HG_PATH" to identify the file,
       and "$HG_METADATA" with a map of fixer names to metadata values from fixer
       tools that affected the file. Fixer tools that didn't affect the file have a
       valueof None. Only fixer tools that executed are present in the metadata.
   
     "postfix"
       Run once after all files and revisions have been handled. Provides
       "$HG_REPLACEMENTS" with information about what revisions were created and
       made obsolete. Provides a boolean "$HG_WDIRWRITTEN" to indicate whether any
       files in the working copy were updated. Provides a list "$HG_METADATA"
       mapping fixer tool names to lists of metadata values returned from
       executions that modified a file. This aggregates the same metadata
       previously passed to the "postfixfile" hook.
   
   Fixer tools are run the in repository's root directory. This allows them to
   read configuration files from the working copy, or even write to the working
   copy. The working copy is not updated to match the revision being fixed. In
   fact, several revisions may be fixed in parallel. Writes to the working copy
   are not amended into the revision being fixed; fixer tools should always write
   fixed file content back to stdout as documented above.
   
   list of commands:
   
    fix           rewrite file content in changesets or working directory
   
   (use 'hg help -v -e fix' to show built-in aliases and global options)
 
 There is no default behavior in the absence of --rev and --working-dir.
 
   $ hg init badusage
   $ cd badusage
 
   $ hg fix
   abort: no changesets specified
   (use --rev or --working-dir)
   [255]
   $ hg fix --whole
   abort: no changesets specified
   (use --rev or --working-dir)
   [255]
   $ hg fix --base 0
   abort: no changesets specified
   (use --rev or --working-dir)
   [255]
 
 Fixing a public revision isn't allowed. It should abort early enough that
 nothing happens, even to the working directory.
 
   $ printf "hello\n" > hello.whole
   $ hg commit -Aqm "hello"
   $ hg phase -r 0 --public
   $ hg fix -r 0
   abort: can't fix immutable changeset 0:6470986d2e7b
   [255]
   $ hg fix -r 0 --working-dir
   abort: can't fix immutable changeset 0:6470986d2e7b
   [255]
   $ hg cat -r tip hello.whole
   hello
   $ cat hello.whole
   hello
 
   $ cd ..
 
 Fixing a clean working directory should do nothing. Even the --whole flag
 shouldn't cause any clean files to be fixed. Specifying a clean file explicitly
 should only fix it if the fixer always fixes the whole file. The combination of
 an explicit filename and --whole should format the entire file regardless.
 
   $ hg init fixcleanwdir
   $ cd fixcleanwdir
 
   $ printf "hello\n" > hello.changed
   $ printf "world\n" > hello.whole
   $ hg commit -Aqm "foo"
   $ hg fix --working-dir
   $ hg diff
   $ hg fix --working-dir --whole
   $ hg diff
   $ hg fix --working-dir *
   $ cat *
   hello
   WORLD
   $ hg revert --all --no-backup
   reverting hello.whole
   $ hg fix --working-dir * --whole
   $ cat *
   HELLO
   WORLD
 
 The same ideas apply to fixing a revision, so we create a revision that doesn't
 modify either of the files in question and try fixing it. This also tests that
 we ignore a file that doesn't match any configured fixer.
 
   $ hg revert --all --no-backup
   reverting hello.changed
   reverting hello.whole
   $ printf "unimportant\n" > some.file
   $ hg commit -Aqm "some other file"
 
   $ hg fix -r .
   $ hg cat -r tip *
   hello
   world
   unimportant
   $ hg fix -r . --whole
   $ hg cat -r tip *
   hello
   world
   unimportant
   $ hg fix -r . *
   $ hg cat -r tip *
   hello
   WORLD
   unimportant
   $ hg fix -r . * --whole --config experimental.evolution.allowdivergence=true
   2 new content-divergent changesets
   $ hg cat -r tip *
   HELLO
   WORLD
   unimportant
 
   $ cd ..
 
 Fixing the working directory should still work if there are no revisions.
 
   $ hg init norevisions
   $ cd norevisions
 
   $ printf "something\n" > something.whole
   $ hg add
   adding something.whole
   $ hg fix --working-dir
   $ cat something.whole
   SOMETHING
 
   $ cd ..
 
 Test the effect of fixing the working directory for each possible status, with
 and without providing explicit file arguments.
 
   $ hg init implicitlyfixstatus
   $ cd implicitlyfixstatus
 
   $ printf "modified\n" > modified.whole
   $ printf "removed\n" > removed.whole
   $ printf "deleted\n" > deleted.whole
   $ printf "clean\n" > clean.whole
   $ printf "ignored.whole" > .hgignore
   $ hg commit -Aqm "stuff"
 
   $ printf "modified!!!\n" > modified.whole
   $ printf "unknown\n" > unknown.whole
   $ printf "ignored\n" > ignored.whole
   $ printf "added\n" > added.whole
   $ hg add added.whole
   $ hg remove removed.whole
   $ rm deleted.whole
 
   $ hg status --all
   M modified.whole
   A added.whole
   R removed.whole
   ! deleted.whole
   ? unknown.whole
   I ignored.whole
   C .hgignore
   C clean.whole
 
   $ hg fix --working-dir
 
   $ hg status --all
   M modified.whole
   A added.whole
   R removed.whole
   ! deleted.whole
   ? unknown.whole
   I ignored.whole
   C .hgignore
   C clean.whole
 
   $ cat *.whole
   ADDED
   clean
   ignored
   MODIFIED!!!
   unknown
 
   $ printf "modified!!!\n" > modified.whole
   $ printf "added\n" > added.whole
 
 Listing the files explicitly causes untracked files to also be fixed, but
 ignored files are still unaffected.
 
   $ hg fix --working-dir *.whole
 
   $ hg status --all
   M clean.whole
   M modified.whole
   A added.whole
   R removed.whole
   ! deleted.whole
   ? unknown.whole
   I ignored.whole
   C .hgignore
 
   $ cat *.whole
   ADDED
   CLEAN
   ignored
   MODIFIED!!!
   UNKNOWN
 
   $ cd ..
 
 Test that incremental fixing works on files with additions, deletions, and
 changes in multiple line ranges. Note that deletions do not generally cause
 neighboring lines to be fixed, so we don't return a line range for purely
 deleted sections. In the future we should support a :deletion config that
 allows fixers to know where deletions are located.
 
   $ hg init incrementalfixedlines
   $ cd incrementalfixedlines
 
   $ printf "a\nb\nc\nd\ne\nf\ng\n" > foo.txt
   $ hg commit -Aqm "foo"
   $ printf "zz\na\nc\ndd\nee\nff\nf\ngg\n" > foo.txt
 
   $ hg --config "fix.fail:command=echo" \
   >    --config "fix.fail:linerange={first}:{last}" \
   >    --config "fix.fail:pattern=foo.txt" \
   >    fix --working-dir
   $ cat foo.txt
   1:1 4:6 8:8
 
   $ cd ..
 
 Test that --whole fixes all lines regardless of the diffs present.
 
   $ hg init wholeignoresdiffs
   $ cd wholeignoresdiffs
 
   $ printf "a\nb\nc\nd\ne\nf\ng\n" > foo.changed
   $ hg commit -Aqm "foo"
   $ printf "zz\na\nc\ndd\nee\nff\nf\ngg\n" > foo.changed
 
   $ hg fix --working-dir
   $ cat foo.changed
   ZZ
   a
   c
   DD
   EE
   FF
   f
   GG
 
   $ hg fix --working-dir --whole
   $ cat foo.changed
   ZZ
   A
   C
   DD
   EE
   FF
   F
   GG
 
   $ cd ..
 
 We should do nothing with symlinks, and their targets should be unaffected. Any
 other behavior would be more complicated to implement and harder to document.
 
 #if symlink
   $ hg init dontmesswithsymlinks
   $ cd dontmesswithsymlinks
 
   $ printf "hello\n" > hello.whole
   $ ln -s hello.whole hellolink
   $ hg add
   adding hello.whole
   adding hellolink
   $ hg fix --working-dir hellolink
   $ hg status
   A hello.whole
   A hellolink
 
   $ cd ..
 #endif
 
 We should allow fixers to run on binary files, even though this doesn't sound
 like a common use case. There's not much benefit to disallowing it, and users
 can add "and not binary()" to their filesets if needed. The Mercurial
 philosophy is generally to not handle binary files specially anyway.
 
   $ hg init cantouchbinaryfiles
   $ cd cantouchbinaryfiles
 
   $ printf "hello\0\n" > hello.whole
   $ hg add
   adding hello.whole
   $ hg fix --working-dir 'set:binary()'
   $ cat hello.whole
   HELLO\x00 (esc)
 
   $ cd ..
 
 We have a config for the maximum size of file we will attempt to fix. This can
 be helpful to avoid running unsuspecting fixer tools on huge inputs, which
 could happen by accident without a well considered configuration. A more
 precise configuration could use the size() fileset function if one global limit
 is undesired.
 
   $ hg init maxfilesize
   $ cd maxfilesize
 
   $ printf "this file is huge\n" > hello.whole
   $ hg add
   adding hello.whole
   $ hg --config fix.maxfilesize=10 fix --working-dir
   ignoring file larger than 10 bytes: hello.whole
   $ cat hello.whole
   this file is huge
 
   $ cd ..
 
 If we specify a file to fix, other files should be left alone, even if they
 have changes.
 
   $ hg init fixonlywhatitellyouto
   $ cd fixonlywhatitellyouto
 
   $ printf "fix me!\n" > fixme.whole
   $ printf "not me.\n" > notme.whole
   $ hg add
   adding fixme.whole
   adding notme.whole
   $ hg fix --working-dir fixme.whole
   $ cat *.whole
   FIX ME!
   not me.
 
   $ cd ..
 
 If we try to fix a missing file, we still fix other files.
 
   $ hg init fixmissingfile
   $ cd fixmissingfile
 
   $ printf "fix me!\n" > foo.whole
   $ hg add
   adding foo.whole
   $ hg fix --working-dir foo.whole bar.whole
   bar.whole: $ENOENT$
   $ cat *.whole
   FIX ME!
 
   $ cd ..
 
 Specifying a directory name should fix all its files and subdirectories.
 
   $ hg init fixdirectory
   $ cd fixdirectory
 
   $ mkdir -p dir1/dir2
   $ printf "foo\n" > foo.whole
   $ printf "bar\n" > dir1/bar.whole
   $ printf "baz\n" > dir1/dir2/baz.whole
   $ hg add
   adding dir1/bar.whole
   adding dir1/dir2/baz.whole
   adding foo.whole
   $ hg fix --working-dir dir1
   $ cat foo.whole dir1/bar.whole dir1/dir2/baz.whole
   foo
   BAR
   BAZ
 
   $ cd ..
 
 Fixing a file in the working directory that needs no fixes should not actually
 write back to the file, so for example the mtime shouldn't change.
 
   $ hg init donttouchunfixedfiles
   $ cd donttouchunfixedfiles
 
   $ printf "NO FIX NEEDED\n" > foo.whole
   $ hg add
   adding foo.whole
   $ cp -p foo.whole foo.whole.orig
   $ cp -p foo.whole.orig foo.whole
   $ sleep 2 # mtime has a resolution of one or two seconds.
   $ hg fix --working-dir
   $ f foo.whole.orig --newer foo.whole
   foo.whole.orig: newer than foo.whole
 
   $ cd ..
 
 When a fixer prints to stderr, we don't assume that it has failed. We show the
 error messages to the user, and we still let the fixer affect the file it was
 fixing if its exit code is zero. Some code formatters might emit error messages
 on stderr and nothing on stdout, which would cause us the clear the file,
 except that they also exit with a non-zero code. We show the user which fixer
 emitted the stderr, and which revision, but we assume that the fixer will print
 the filename if it is relevant (since the issue may be non-specific). There is
 also a config to abort (without affecting any files whatsoever) if we see any
 tool with a non-zero exit status.
 
   $ hg init showstderr
   $ cd showstderr
 
   $ printf "hello\n" > hello.txt
   $ hg add
   adding hello.txt
   $ cat > $TESTTMP/work.sh <<'EOF'
   > printf 'HELLO\n'
   > printf "$@: some\nerror that didn't stop the tool" >&2
   > exit 0 # success despite the stderr output
   > EOF
   $ hg --config "fix.work:command=sh $TESTTMP/work.sh {rootpath}" \
   >    --config "fix.work:pattern=hello.txt" \
   >    fix --working-dir
   [wdir] work: hello.txt: some
   [wdir] work: error that didn't stop the tool
   $ cat hello.txt
   HELLO
 
   $ printf "goodbye\n" > hello.txt
   $ printf "foo\n" > foo.whole
   $ hg add
   adding foo.whole
   $ cat > $TESTTMP/fail.sh <<'EOF'
   > printf 'GOODBYE\n'
   > printf "$@: some\nerror that did stop the tool\n" >&2
   > exit 42 # success despite the stdout output
   > EOF
   $ hg --config "fix.fail:command=sh $TESTTMP/fail.sh {rootpath}" \
   >    --config "fix.fail:pattern=hello.txt" \
   >    --config "fix.failure=abort" \
   >    fix --working-dir
   [wdir] fail: hello.txt: some
   [wdir] fail: error that did stop the tool
   abort: no fixes will be applied
   (use --config fix.failure=continue to apply any successful fixes anyway)
   [255]
   $ cat hello.txt
   goodbye
   $ cat foo.whole
   foo
 
   $ hg --config "fix.fail:command=sh $TESTTMP/fail.sh {rootpath}" \
   >    --config "fix.fail:pattern=hello.txt" \
   >    fix --working-dir
   [wdir] fail: hello.txt: some
   [wdir] fail: error that did stop the tool
   $ cat hello.txt
   goodbye
   $ cat foo.whole
   FOO
 
   $ hg --config "fix.fail:command=exit 42" \
   >    --config "fix.fail:pattern=hello.txt" \
   >    fix --working-dir
   [wdir] fail: exited with status 42
 
   $ cd ..
 
 Fixing the working directory and its parent revision at the same time should
 check out the replacement revision for the parent. This prevents any new
 uncommitted changes from appearing. We test this for a clean working directory
 and a dirty one. In both cases, all lines/files changed since the grandparent
 will be fixed. The grandparent is the "baserev" for both the parent and the
 working copy.
 
   $ hg init fixdotandcleanwdir
   $ cd fixdotandcleanwdir
 
   $ printf "hello\n" > hello.whole
   $ printf "world\n" > world.whole
   $ hg commit -Aqm "the parent commit"
 
   $ hg parents --template '{rev} {desc}\n'
   0 the parent commit
   $ hg fix --working-dir -r .
   $ hg parents --template '{rev} {desc}\n'
   1 the parent commit
   $ hg cat -r . *.whole
   HELLO
   WORLD
   $ cat *.whole
   HELLO
   WORLD
   $ hg status
 
   $ cd ..
 
 Same test with a dirty working copy.
 
   $ hg init fixdotanddirtywdir
   $ cd fixdotanddirtywdir
 
   $ printf "hello\n" > hello.whole
   $ printf "world\n" > world.whole
   $ hg commit -Aqm "the parent commit"
 
   $ printf "hello,\n" > hello.whole
   $ printf "world!\n" > world.whole
 
   $ hg parents --template '{rev} {desc}\n'
   0 the parent commit
   $ hg fix --working-dir -r .
   $ hg parents --template '{rev} {desc}\n'
   1 the parent commit
   $ hg cat -r . *.whole
   HELLO
   WORLD
   $ cat *.whole
   HELLO,
   WORLD!
   $ hg status
   M hello.whole
   M world.whole
 
   $ cd ..
 
 When we have a chain of commits that change mutually exclusive lines of code,
 we should be able to do incremental fixing that causes each commit in the chain
 to include fixes made to the previous commits. This prevents children from
 backing out the fixes made in their parents. A dirty working directory is
 conceptually similar to another commit in the chain.
 
   $ hg init incrementallyfixchain
   $ cd incrementallyfixchain
 
   $ cat > file.changed <<EOF
   > first
   > second
   > third
   > fourth
   > fifth
   > EOF
   $ hg commit -Aqm "the common ancestor (the baserev)"
   $ cat > file.changed <<EOF
   > first (changed)
   > second
   > third
   > fourth
   > fifth
   > EOF
   $ hg commit -Aqm "the first commit to fix"
   $ cat > file.changed <<EOF
   > first (changed)
   > second
   > third (changed)
   > fourth
   > fifth
   > EOF
   $ hg commit -Aqm "the second commit to fix"
   $ cat > file.changed <<EOF
   > first (changed)
   > second
   > third (changed)
   > fourth
   > fifth (changed)
   > EOF
 
   $ hg fix -r . -r '.^' --working-dir
 
   $ hg parents --template '{rev}\n'
   4
   $ hg cat -r '.^^' file.changed
   first
   second
   third
   fourth
   fifth
   $ hg cat -r '.^' file.changed
   FIRST (CHANGED)
   second
   third
   fourth
   fifth
   $ hg cat -r . file.changed
   FIRST (CHANGED)
   second
   THIRD (CHANGED)
   fourth
   fifth
   $ cat file.changed
   FIRST (CHANGED)
   second
   THIRD (CHANGED)
   fourth
   FIFTH (CHANGED)
 
   $ cd ..
 
 If we incrementally fix a merge commit, we should fix any lines that changed
 versus either parent. You could imagine only fixing the intersection or some
 other subset, but this is necessary if either parent is being fixed. It
 prevents us from forgetting fixes made in either parent.
 
   $ hg init incrementallyfixmergecommit
   $ cd incrementallyfixmergecommit
 
   $ printf "a\nb\nc\n" > file.changed
   $ hg commit -Aqm "ancestor"
 
   $ printf "aa\nb\nc\n" > file.changed
   $ hg commit -m "change a"
 
   $ hg checkout '.^'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ printf "a\nb\ncc\n" > file.changed
   $ hg commit -m "change c"
   created new head
 
   $ hg merge
   merging file.changed
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg commit -m "merge"
   $ hg cat -r . file.changed
   aa
   b
   cc
 
   $ hg fix -r . --working-dir
   $ hg cat -r . file.changed
   AA
   b
   CC
 
   $ cd ..
 
 Abort fixing revisions if there is an unfinished operation. We don't want to
 make things worse by editing files or stripping/obsoleting things. Also abort
 fixing the working directory if there are unresolved merge conflicts.
 
   $ hg init abortunresolved
   $ cd abortunresolved
 
   $ echo "foo1" > foo.whole
   $ hg commit -Aqm "foo 1"
 
   $ hg update null
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "foo2" > foo.whole
   $ hg commit -Aqm "foo 2"
 
   $ hg --config extensions.rebase= rebase -r 1 -d 0
   rebasing 1:c3b6dc0e177a "foo 2" (tip)
   merging foo.whole
   warning: conflicts while merging foo.whole! (edit, then use 'hg resolve --mark')
   unresolved conflicts (see hg resolve, then hg rebase --continue)
   [1]
 
   $ hg --config extensions.rebase= fix --working-dir
   abort: unresolved conflicts
   (use 'hg resolve')
   [255]
 
   $ hg --config extensions.rebase= fix -r .
   abort: rebase in progress
   (use 'hg rebase --continue' or 'hg rebase --abort')
   [255]
 
   $ cd ..
 
 When fixing a file that was renamed, we should diff against the source of the
 rename for incremental fixing and we should correctly reproduce the rename in
 the replacement revision.
 
   $ hg init fixrenamecommit
   $ cd fixrenamecommit
 
   $ printf "a\nb\nc\n" > source.changed
   $ hg commit -Aqm "source revision"
   $ hg move source.changed dest.changed
   $ printf "a\nb\ncc\n" > dest.changed
   $ hg commit -m "dest revision"
 
   $ hg fix -r .
   $ hg log -r tip --copies --template "{file_copies}\n"
   dest.changed (source.changed)
   $ hg cat -r tip dest.changed
   a
   b
   CC
 
   $ cd ..
 
 When fixing revisions that remove files we must ensure that the replacement
 actually removes the file, whereas it could accidentally leave it unchanged or
 write an empty string to it.
 
   $ hg init fixremovedfile
   $ cd fixremovedfile
 
   $ printf "foo\n" > foo.whole
   $ printf "bar\n" > bar.whole
   $ hg commit -Aqm "add files"
   $ hg remove bar.whole
   $ hg commit -m "remove file"
   $ hg status --change .
   R bar.whole
   $ hg fix -r . foo.whole
   $ hg status --change tip
   M foo.whole
   R bar.whole
 
   $ cd ..
 
 If fixing a revision finds no fixes to make, no replacement revision should be
 created.
 
   $ hg init nofixesneeded
   $ cd nofixesneeded
 
   $ printf "FOO\n" > foo.whole
   $ hg commit -Aqm "add file"
   $ hg log --template '{rev}\n'
   0
   $ hg fix -r .
   $ hg log --template '{rev}\n'
   0
 
   $ cd ..
 
 If fixing a commit reverts all the changes in the commit, we replace it with a
 commit that changes no files.
 
   $ hg init nochangesleft
   $ cd nochangesleft
 
   $ printf "FOO\n" > foo.whole
   $ hg commit -Aqm "add file"
   $ printf "foo\n" > foo.whole
   $ hg commit -m "edit file"
   $ hg status --change .
   M foo.whole
   $ hg fix -r .
   $ hg status --change tip
 
   $ cd ..
 
 If we fix a parent and child revision together, the child revision must be
 replaced if the parent is replaced, even if the diffs of the child needed no
 fixes. However, we're free to not replace revisions that need no fixes and have
 no ancestors that are replaced.
 
   $ hg init mustreplacechild
   $ cd mustreplacechild
 
   $ printf "FOO\n" > foo.whole
   $ hg commit -Aqm "add foo"
   $ printf "foo\n" > foo.whole
   $ hg commit -m "edit foo"
   $ printf "BAR\n" > bar.whole
   $ hg commit -Aqm "add bar"
 
   $ hg log --graph --template '{rev} {files}'
   @  2 bar.whole
   |
   o  1 foo.whole
   |
   o  0 foo.whole
   
   $ hg fix -r 0:2
   $ hg log --graph --template '{rev} {files}'
   o  4 bar.whole
   |
   o  3
   |
   | @  2 bar.whole
   | |
   | x  1 foo.whole
   |/
   o  0 foo.whole
   
 
   $ cd ..
 
 It's also possible that the child needs absolutely no changes, but we still
 need to replace it to update its parent. If we skipped replacing the child
 because it had no file content changes, it would become an orphan for no good
 reason.
 
   $ hg init mustreplacechildevenifnop
   $ cd mustreplacechildevenifnop
 
   $ printf "Foo\n" > foo.whole
   $ hg commit -Aqm "add a bad foo"
   $ printf "FOO\n" > foo.whole
   $ hg commit -m "add a good foo"
   $ hg fix -r . -r '.^'
   $ hg log --graph --template '{rev} {desc}'
   o  3 add a good foo
   |
   o  2 add a bad foo
   
   @  1 add a good foo
   |
   x  0 add a bad foo
   
 
   $ cd ..
 
 Similar to the case above, the child revision may become empty as a result of
 fixing its parent. We should still create an empty replacement child.
 TODO: determine how this should interact with ui.allowemptycommit given that
 the empty replacement could have children.
 
   $ hg init mustreplacechildevenifempty
   $ cd mustreplacechildevenifempty
 
   $ printf "foo\n" > foo.whole
   $ hg commit -Aqm "add foo"
   $ printf "Foo\n" > foo.whole
   $ hg commit -m "edit foo"
   $ hg fix -r . -r '.^'
   $ hg log --graph --template '{rev} {desc}\n' --stat
   o  3 edit foo
   |
   o  2 add foo
       foo.whole |  1 +
       1 files changed, 1 insertions(+), 0 deletions(-)
   
   @  1 edit foo
   |   foo.whole |  2 +-
   |   1 files changed, 1 insertions(+), 1 deletions(-)
   |
   x  0 add foo
       foo.whole |  1 +
       1 files changed, 1 insertions(+), 0 deletions(-)
   
 
   $ cd ..
 
 Fixing a secret commit should replace it with another secret commit.
 
   $ hg init fixsecretcommit
   $ cd fixsecretcommit
 
   $ printf "foo\n" > foo.whole
   $ hg commit -Aqm "add foo" --secret
   $ hg fix -r .
   $ hg log --template '{rev} {phase}\n'
   1 secret
   0 secret
 
   $ cd ..
 
 We should also preserve phase when fixing a draft commit while the user has
 their default set to secret.
 
   $ hg init respectphasesnewcommit
   $ cd respectphasesnewcommit
 
   $ printf "foo\n" > foo.whole
   $ hg commit -Aqm "add foo"
   $ hg --config phases.newcommit=secret fix -r .
   $ hg log --template '{rev} {phase}\n'
   1 draft
   0 draft
 
   $ cd ..
 
 Debug output should show what fixer commands are being subprocessed, which is
 useful for anyone trying to set up a new config.
 
   $ hg init debugoutput
   $ cd debugoutput
 
   $ printf "foo\nbar\nbaz\n" > foo.changed
   $ hg commit -Aqm "foo"
   $ printf "Foo\nbar\nBaz\n" > foo.changed
   $ hg --debug fix --working-dir
   subprocess: * $TESTTMP/uppercase.py 1-1 3-3 (glob)
 
   $ cd ..
 
 Fixing an obsolete revision can cause divergence, so we abort unless the user
 configures to allow it. This is not yet smart enough to know whether there is a
 successor, but even then it is not likely intentional or idiomatic to fix an
 obsolete revision.
 
   $ hg init abortobsoleterev
   $ cd abortobsoleterev
 
   $ printf "foo\n" > foo.changed
   $ hg commit -Aqm "foo"
   $ hg debugobsolete `hg parents --template '{node}'`
   obsoleted 1 changesets
   $ hg --hidden fix -r 0
   abort: fixing obsolete revision could cause divergence
   [255]
 
   $ hg --hidden fix -r 0 --config experimental.evolution.allowdivergence=true
   $ hg cat -r tip foo.changed
   FOO
 
   $ cd ..
 
 Test all of the available substitution values for fixer commands.
 
   $ hg init substitution
   $ cd substitution
 
   $ mkdir foo
   $ printf "hello\ngoodbye\n" > foo/bar
   $ hg add
   adding foo/bar
   $ hg --config "fix.fail:command=printf '%s\n' '{rootpath}' '{basename}'" \
   >    --config "fix.fail:linerange='{first}' '{last}'" \
   >    --config "fix.fail:pattern=foo/bar" \
   >    fix --working-dir
   $ cat foo/bar
   foo/bar
   bar
   1
   2
 
   $ cd ..
 
 The --base flag should allow picking the revisions to diff against for changed
 files and incremental line formatting.
 
   $ hg init baseflag
   $ cd baseflag
 
   $ printf "one\ntwo\n" > foo.changed
   $ printf "bar\n" > bar.changed
   $ hg commit -Aqm "first"
   $ printf "one\nTwo\n" > foo.changed
   $ hg commit -m "second"
   $ hg fix -w --base .
   $ hg status
   $ hg fix -w --base null
   $ cat foo.changed
   ONE
   TWO
   $ cat bar.changed
   BAR
 
   $ cd ..
 
 If the user asks to fix the parent of another commit, they are asking to create
 an orphan. We must respect experimental.evolution.allowunstable.
 
   $ hg init allowunstable
   $ cd allowunstable
 
   $ printf "one\n" > foo.whole
   $ hg commit -Aqm "first"
   $ printf "two\n" > foo.whole
   $ hg commit -m "second"
   $ hg --config experimental.evolution.allowunstable=False fix -r '.^'
   abort: can only fix a changeset together with all its descendants
   [255]
   $ hg fix -r '.^'
   1 new orphan changesets
   $ hg cat -r 2 foo.whole
   ONE
 
   $ cd ..
 
 The --base flag affects the set of files being fixed. So while the --whole flag
 makes the base irrelevant for changed line ranges, it still changes the
 meaning and effect of the command. In this example, no files or lines are fixed
 until we specify the base, but then we do fix unchanged lines.
 
   $ hg init basewhole
   $ cd basewhole
   $ printf "foo1\n" > foo.changed
   $ hg commit -Aqm "first"
   $ printf "foo2\n" >> foo.changed
   $ printf "bar\n" > bar.changed
   $ hg commit -Aqm "second"
 
   $ hg fix --working-dir --whole
   $ cat *.changed
   bar
   foo1
   foo2
 
   $ hg fix --working-dir --base 0 --whole
   $ cat *.changed
   BAR
   FOO1
   FOO2
 
   $ cd ..
 
 The execution order of tools can be controlled. This example doesn't work if
 you sort after truncating, but the config defines the correct order while the
 definitions are out of order (which might imply the incorrect order given the
 implementation of fix). The goal is to use multiple tools to select the lowest
 5 numbers in the file.
 
   $ hg init priorityexample
   $ cd priorityexample
 
   $ cat >> .hg/hgrc <<EOF
   > [fix]
   > head:command = head -n 5
   > head:pattern = numbers.txt
   > head:priority = 1
   > sort:command = sort -n
   > sort:pattern = numbers.txt
   > sort:priority = 2
   > EOF
 
   $ printf "8\n2\n3\n6\n7\n4\n9\n5\n1\n0\n" > numbers.txt
   $ hg add -q
   $ hg fix -w
   $ cat numbers.txt
   0
   1
   2
   3
   4
 
 And of course we should be able to break this by reversing the execution order.
 Test negative priorities while we're at it.
 
   $ cat >> .hg/hgrc <<EOF
   > [fix]
   > head:priority = -1
   > sort:priority = -2
   > EOF
   $ printf "8\n2\n3\n6\n7\n4\n9\n5\n1\n0\n" > numbers.txt
   $ hg fix -w
   $ cat numbers.txt
   2
   3
   6
   7
   8
 
   $ cd ..
 
 It's possible for repeated applications of a fixer tool to create cycles in the
 generated content of a file. For example, two users with different versions of
 a code formatter might fight over the formatting when they run hg fix. In the
 absence of other changes, this means we could produce commits with the same
 hash in subsequent runs of hg fix. This is a problem unless we support
 obsolescence cycles well. We avoid this by adding an extra field to the
 successor which forces it to have a new hash. That's why this test creates
 three revisions instead of two.
 
   $ hg init cyclictool
   $ cd cyclictool
 
   $ cat >> .hg/hgrc <<EOF
   > [fix]
   > swapletters:command = tr ab ba
   > swapletters:pattern = foo
   > EOF
 
   $ echo ab > foo
   $ hg commit -Aqm foo
 
   $ hg fix -r 0
   $ hg fix -r 1
 
   $ hg cat -r 0 foo --hidden
   ab
   $ hg cat -r 1 foo --hidden
   ba
   $ hg cat -r 2 foo
   ab
 
   $ cd ..
 
 We run fixer tools in the repo root so they can look for config files or other
 important things in the working directory. This does NOT mean we are
 reconstructing a working copy of every revision being fixed; we're just giving
 the tool knowledge of the repo's location in case it can do something
 reasonable with that.
 
   $ hg init subprocesscwd
   $ cd subprocesscwd
 
   $ cat >> .hg/hgrc <<EOF
   > [fix]
   > printcwd:command = pwd
   > printcwd:pattern = path:foo/bar
   > EOF
 
   $ mkdir foo
   $ printf "bar\n" > foo/bar
   $ hg commit -Aqm blah
 
   $ hg fix -w -r . foo/bar
   $ hg cat -r tip foo/bar
   $TESTTMP/subprocesscwd
   $ cat foo/bar
   $TESTTMP/subprocesscwd
 
   $ cd foo
 
   $ hg fix -w -r . bar
   $ hg cat -r tip bar
   $TESTTMP/subprocesscwd
   $ cat bar
   $TESTTMP/subprocesscwd
 
   $ cd ../..
 
 Tools configured without a pattern are ignored. It would be too dangerous to
 run them on all files, because this might happen while testing a configuration
 that also deletes all of the file content. There is no reasonable subset of the
 files to use as a default. Users should be explicit about what files are
 affected by a tool. This test also confirms that we don't crash when the
 pattern config is missing, and that we only warn about it once.
 
   $ hg init nopatternconfigured
   $ cd nopatternconfigured
 
   $ printf "foo" > foo
   $ printf "bar" > bar
   $ hg add -q
   $ hg fix --debug --working-dir --config "fix.nopattern:command=echo fixed"
   fixer tool has no pattern configuration: nopattern
   $ cat foo bar
   foobar (no-eol)
 
   $ cd ..
 
 Test that we can configure a fixer to affect all files regardless of the cwd.
 The way we invoke matching must not prohibit this.
 
   $ hg init affectallfiles
   $ cd affectallfiles
 
   $ mkdir foo bar
   $ printf "foo" > foo/file
   $ printf "bar" > bar/file
   $ printf "baz" > baz_file
   $ hg add -q
 
   $ cd bar
   $ hg fix --working-dir --config "fix.cooltool:command=echo fixed" \
   >                      --config "fix.cooltool:pattern=rootglob:**"
   $ cd ..
 
   $ cat foo/file
   fixed
   $ cat bar/file
   fixed
   $ cat baz_file
   fixed
 
   $ cd ..
+
+Tools should be able to run on unchanged files, even if they set :linerange.
+This includes a corner case where deleted chunks of a file are not considered
+changes.
+
+  $ hg init skipclean
+  $ cd skipclean
+
+  $ printf "a\nb\nc\n" > foo
+  $ printf "a\nb\nc\n" > bar
+  $ printf "a\nb\nc\n" > baz
+  $ hg commit -Aqm "base"
+
+  $ printf "a\nc\n" > foo
+  $ printf "a\nx\nc\n" > baz
+
+  $ hg fix --working-dir foo bar baz \
+  >        --config 'fix.changedlines:command=printf "Line ranges:\n"; ' \
+  >        --config 'fix.changedlines:linerange=printf "{first} through {last}\n"; ' \
+  >        --config 'fix.changedlines:pattern=rootglob:**' \
+  >        --config 'fix.changedlines:skipclean=false'
+
+  $ cat foo
+  Line ranges:
+  $ cat bar
+  Line ranges:
+  $ cat baz
+  Line ranges:
+  2 through 2
+
+  $ cd ..