filemerge: add a before-merge callback to internal merge tools

We're going to separate the pre-merge and merge steps for merge tools. The
merge step will be specific to the tool, but the pre-merge step will be common
to all merge tools that need it.

However, some merge tools run checks *before* the pre-merge step. This callback
will allow that to continue to work.

mercurial/filemerge.py

@@ -1,547 +1,548 b''
 # filemerge.py - file-level merge handling for Mercurial
 #
 # Copyright 2006, 2007, 2008 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 filecmp
 import os
 import re
 import tempfile
 
 from .i18n import _
 from .node import short
 
 from . import (
     error,
     match,
     simplemerge,
     tagmerge,
     templatekw,
     templater,
     util,
 )
 
 def _toolstr(ui, tool, part, default=""):
     return ui.config("merge-tools", tool + "." + part, default)
 
 def _toolbool(ui, tool, part, default=False):
     return ui.configbool("merge-tools", tool + "." + part, default)
 
 def _toollist(ui, tool, part, default=[]):
     return ui.configlist("merge-tools", tool + "." + part, default)
 
 internals = {}
 # Merge tools to document.
 internalsdoc = {}
 
-def internaltool(name, trymerge, onfailure=None):
+def internaltool(name, trymerge, onfailure=None, precheck=None):
     '''return a decorator for populating internal merge tool table'''
     def decorator(func):
         fullname = ':' + name
         func.__doc__ = "``%s``\n" % fullname + func.__doc__.strip()
         internals[fullname] = func
         internals['internal:' + name] = func
         internalsdoc[fullname] = func
         func.trymerge = trymerge
         func.onfailure = onfailure
+        func.precheck = precheck
         return func
     return decorator
 
 def _findtool(ui, tool):
     if tool in internals:
         return tool
     return findexternaltool(ui, tool)
 
 def findexternaltool(ui, tool):
     for kn in ("regkey", "regkeyalt"):
         k = _toolstr(ui, tool, kn)
         if not k:
             continue
         p = util.lookupreg(k, _toolstr(ui, tool, "regname"))
         if p:
             p = util.findexe(p + _toolstr(ui, tool, "regappend"))
             if p:
                 return p
     exe = _toolstr(ui, tool, "executable", tool)
     return util.findexe(util.expandpath(exe))
 
 def _picktool(repo, ui, path, binary, symlink):
     def check(tool, pat, symlink, binary):
         tmsg = tool
         if pat:
             tmsg += " specified for " + pat
         if not _findtool(ui, tool):
             if pat: # explicitly requested tool deserves a warning
                 ui.warn(_("couldn't find merge tool %s\n") % tmsg)
             else: # configured but non-existing tools are more silent
                 ui.note(_("couldn't find merge tool %s\n") % tmsg)
         elif symlink and not _toolbool(ui, tool, "symlink"):
             ui.warn(_("tool %s can't handle symlinks\n") % tmsg)
         elif binary and not _toolbool(ui, tool, "binary"):
             ui.warn(_("tool %s can't handle binary\n") % tmsg)
         elif not util.gui() and _toolbool(ui, tool, "gui"):
             ui.warn(_("tool %s requires a GUI\n") % tmsg)
         else:
             return True
         return False
 
     # internal config: ui.forcemerge
     # forcemerge comes from command line arguments, highest priority
     force = ui.config('ui', 'forcemerge')
     if force:
         toolpath = _findtool(ui, force)
         if toolpath:
             return (force, util.shellquote(toolpath))
         else:
             # mimic HGMERGE if given tool not found
             return (force, force)
 
     # HGMERGE takes next precedence
     hgmerge = os.environ.get("HGMERGE")
     if hgmerge:
         return (hgmerge, hgmerge)
 
     # then patterns
     for pat, tool in ui.configitems("merge-patterns"):
         mf = match.match(repo.root, '', [pat])
         if mf(path) and check(tool, pat, symlink, False):
             toolpath = _findtool(ui, tool)
             return (tool, util.shellquote(toolpath))
 
     # then merge tools
     tools = {}
     for k, v in ui.configitems("merge-tools"):
         t = k.split('.')[0]
         if t not in tools:
             tools[t] = int(_toolstr(ui, t, "priority", "0"))
     names = tools.keys()
     tools = sorted([(-p, t) for t, p in tools.items()])
     uimerge = ui.config("ui", "merge")
     if uimerge:
         if uimerge not in names:
             return (uimerge, uimerge)
         tools.insert(0, (None, uimerge)) # highest priority
     tools.append((None, "hgmerge")) # the old default, if found
     for p, t in tools:
         if check(t, None, symlink, binary):
             toolpath = _findtool(ui, t)
             return (t, util.shellquote(toolpath))
 
     # internal merge or prompt as last resort
     if symlink or binary:
         return ":prompt", None
     return ":merge", None
 
 def _eoltype(data):
     "Guess the EOL type of a file"
     if '\0' in data: # binary
         return None
     if '\r\n' in data: # Windows
         return '\r\n'
     if '\r' in data: # Old Mac
         return '\r'
     if '\n' in data: # UNIX
         return '\n'
     return None # unknown
 
 def _matcheol(file, origfile):
     "Convert EOL markers in a file to match origfile"
     tostyle = _eoltype(util.readfile(origfile))
     if tostyle:
         data = util.readfile(file)
         style = _eoltype(data)
         if style:
             newdata = data.replace(style, tostyle)
             if newdata != data:
                 util.writefile(file, newdata)
 
 @internaltool('prompt', False)
 def _iprompt(repo, mynode, orig, fcd, fco, fca, toolconf):
     """Asks the user which of the local or the other version to keep as
     the merged version."""
     ui = repo.ui
     fd = fcd.path()
 
     if ui.promptchoice(_(" no tool found to merge %s\n"
                          "keep (l)ocal or take (o)ther?"
                          "$$ &Local $$ &Other") % fd, 0):
         return _iother(repo, mynode, orig, fcd, fco, fca, toolconf)
     else:
         return _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf)
 
 @internaltool('local', False)
 def _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf):
     """Uses the local version of files as the merged version."""
     return 0
 
 @internaltool('other', False)
 def _iother(repo, mynode, orig, fcd, fco, fca, toolconf):
     """Uses the other version of files as the merged version."""
     repo.wwrite(fcd.path(), fco.data(), fco.flags())
     return 0
 
 @internaltool('fail', False)
 def _ifail(repo, mynode, orig, fcd, fco, fca, toolconf):
     """
     Rather than attempting to merge files that were modified on both
     branches, it marks them as unresolved. The resolve command must be
     used to resolve these conflicts."""
     return 1
 
 def _premerge(repo, toolconf, files, labels=None):
     tool, toolpath, binary, symlink = toolconf
     if symlink:
         return 1
     a, b, c, back = files
 
     ui = repo.ui
 
     validkeep = ['keep', 'keep-merge3']
 
     # do we attempt to simplemerge first?
     try:
         premerge = _toolbool(ui, tool, "premerge", not binary)
     except error.ConfigError:
         premerge = _toolstr(ui, tool, "premerge").lower()
         if premerge not in validkeep:
             _valid = ', '.join(["'" + v + "'" for v in validkeep])
             raise error.ConfigError(_("%s.premerge not valid "
                                       "('%s' is neither boolean nor %s)") %
                                     (tool, premerge, _valid))
 
     if premerge:
         if premerge == 'keep-merge3':
             if not labels:
                 labels = _defaultconflictlabels
             if len(labels) < 3:
                 labels.append('base')
         r = simplemerge.simplemerge(ui, a, b, c, quiet=True, label=labels)
         if not r:
             ui.debug(" premerge successful\n")
             return 0
         if premerge not in validkeep:
             util.copyfile(back, a) # restore from backup and try again
     return 1 # continue merging
 
 def _merge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels, mode):
     """
     Uses the internal non-interactive simple merge algorithm for merging
     files. It will fail if there are any conflicts and leave markers in
     the partially merged file. Markers will have two sections, one for each side
     of merge, unless mode equals 'union' which suppresses the markers."""
     tool, toolpath, binary, symlink = toolconf
     if symlink:
         repo.ui.warn(_('warning: internal :merge cannot merge symlinks '
                        'for %s\n') % fcd.path())
         return False, 1
     r = _premerge(repo, toolconf, files, labels=labels)
     if r:
         a, b, c, back = files
 
         ui = repo.ui
 
         r = simplemerge.simplemerge(ui, a, b, c, label=labels, mode=mode)
         return True, r
     return False, 0
 
 @internaltool('union', True,
               _("merging %s incomplete! "
                 "(edit conflicts, then use 'hg resolve --mark')\n"))
 def _iunion(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     """
     Uses the internal non-interactive simple merge algorithm for merging
     files. It will use both left and right sides for conflict regions.
     No markers are inserted."""
     return _merge(repo, mynode, orig, fcd, fco, fca, toolconf,
                   files, labels, 'union')
 
 @internaltool('merge', True,
               _("merging %s incomplete! "
                 "(edit conflicts, then use 'hg resolve --mark')\n"))
 def _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     """
     Uses the internal non-interactive simple merge algorithm for merging
     files. It will fail if there are any conflicts and leave markers in
     the partially merged file. Markers will have two sections, one for each side
     of merge."""
     return _merge(repo, mynode, orig, fcd, fco, fca, toolconf,
                   files, labels, 'merge')
 
 @internaltool('merge3', True,
               _("merging %s incomplete! "
                 "(edit conflicts, then use 'hg resolve --mark')\n"))
 def _imerge3(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     """
     Uses the internal non-interactive simple merge algorithm for merging
     files. It will fail if there are any conflicts and leave markers in
     the partially merged file. Marker will have three sections, one from each
     side of the merge and one for the base content."""
     if not labels:
         labels = _defaultconflictlabels
     if len(labels) < 3:
         labels.append('base')
     return _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels)
 
 def _imergeauto(repo, mynode, orig, fcd, fco, fca, toolconf, files,
                 labels=None, localorother=None):
     """
     Generic driver for _imergelocal and _imergeother
     """
     assert localorother is not None
     tool, toolpath, binary, symlink = toolconf
     if symlink:
         repo.ui.warn(_('warning: :merge-%s cannot merge symlinks '
                        'for %s\n') % (localorother, fcd.path()))
         return False, 1
     a, b, c, back = files
     r = simplemerge.simplemerge(repo.ui, a, b, c, label=labels,
                                 localorother=localorother)
     return True, r
 
 @internaltool('merge-local', True)
 def _imergelocal(*args, **kwargs):
     """
     Like :merge, but resolve all conflicts non-interactively in favor
     of the local changes."""
     success, status = _imergeauto(localorother='local', *args, **kwargs)
     return success, status
 
 @internaltool('merge-other', True)
 def _imergeother(*args, **kwargs):
     """
     Like :merge, but resolve all conflicts non-interactively in favor
     of the other changes."""
     success, status = _imergeauto(localorother='other', *args, **kwargs)
     return success, status
 
 @internaltool('tagmerge', True,
               _("automatic tag merging of %s failed! "
                 "(use 'hg resolve --tool :merge' or another merge "
                 "tool of your choice)\n"))
 def _itagmerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     """
     Uses the internal tag merge algorithm (experimental).
     """
     return tagmerge.merge(repo, fcd, fco, fca)
 
 @internaltool('dump', True)
 def _idump(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     """
     Creates three versions of the files to merge, containing the
     contents of local, other and base. These files can then be used to
     perform a merge manually. If the file to be merged is named
     ``a.txt``, these files will accordingly be named ``a.txt.local``,
     ``a.txt.other`` and ``a.txt.base`` and they will be placed in the
     same directory as ``a.txt``."""
     r = _premerge(repo, toolconf, files, labels=labels)
     if r:
         a, b, c, back = files
 
         fd = fcd.path()
 
         util.copyfile(a, a + ".local")
         repo.wwrite(fd + ".other", fco.data(), fco.flags())
         repo.wwrite(fd + ".base", fca.data(), fca.flags())
     return False, r
 
 def _xmerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):
     r = _premerge(repo, toolconf, files, labels=labels)
     if r:
         tool, toolpath, binary, symlink = toolconf
         a, b, c, back = files
         out = ""
         env = {'HG_FILE': fcd.path(),
                'HG_MY_NODE': short(mynode),
                'HG_OTHER_NODE': str(fco.changectx()),
                'HG_BASE_NODE': str(fca.changectx()),
                'HG_MY_ISLINK': 'l' in fcd.flags(),
                'HG_OTHER_ISLINK': 'l' in fco.flags(),
                'HG_BASE_ISLINK': 'l' in fca.flags(),
                }
 
         ui = repo.ui
 
         args = _toolstr(ui, tool, "args", '$local $base $other')
         if "$output" in args:
             out, a = a, back # read input from backup, write to original
         replace = {'local': a, 'base': b, 'other': c, 'output': out}
         args = util.interpolate(r'\$', replace, args,
                                 lambda s: util.shellquote(util.localpath(s)))
         cmd = toolpath + ' ' + args
         repo.ui.debug('launching merge tool: %s\n' % cmd)
         r = ui.system(cmd, cwd=repo.root, environ=env)
         repo.ui.debug('merge tool returned: %s\n' % r)
         return True, r
     return False, 0
 
 def _formatconflictmarker(repo, ctx, template, label, pad):
     """Applies the given template to the ctx, prefixed by the label.
 
     Pad is the minimum width of the label prefix, so that multiple markers
     can have aligned templated parts.
     """
     if ctx.node() is None:
         ctx = ctx.p1()
 
     props = templatekw.keywords.copy()
     props['templ'] = template
     props['ctx'] = ctx
     props['repo'] = repo
     templateresult = template('conflictmarker', **props)
 
     label = ('%s:' % label).ljust(pad + 1)
     mark = '%s %s' % (label, templater.stringify(templateresult))
 
     if mark:
         mark = mark.splitlines()[0] # split for safety
 
     # 8 for the prefix of conflict marker lines (e.g. '<<<<<<< ')
     return util.ellipsis(mark, 80 - 8)
 
 _defaultconflictmarker = ('{node|short} ' +
     '{ifeq(tags, "tip", "", "{tags} ")}' +
     '{if(bookmarks, "{bookmarks} ")}' +
     '{ifeq(branch, "default", "", "{branch} ")}' +
     '- {author|user}: {desc|firstline}')
 
 _defaultconflictlabels = ['local', 'other']
 
 def _formatlabels(repo, fcd, fco, fca, labels):
     """Formats the given labels using the conflict marker template.
 
     Returns a list of formatted labels.
     """
     cd = fcd.changectx()
     co = fco.changectx()
     ca = fca.changectx()
 
     ui = repo.ui
     template = ui.config('ui', 'mergemarkertemplate', _defaultconflictmarker)
     tmpl = templater.templater(None, cache={'conflictmarker': template})
 
     pad = max(len(l) for l in labels)
 
     newlabels = [_formatconflictmarker(repo, cd, tmpl, labels[0], pad),
                  _formatconflictmarker(repo, co, tmpl, labels[1], pad)]
     if len(labels) > 2:
         newlabels.append(_formatconflictmarker(repo, ca, tmpl, labels[2], pad))
     return newlabels
 
 def filemerge(repo, mynode, orig, fcd, fco, fca, labels=None):
     """perform a 3-way merge in the working directory
 
     mynode = parent node before merge
     orig = original local filename before merge
     fco = other file context
     fca = ancestor file context
     fcd = local file context for current/destination file
     """
 
     if True:
         def temp(prefix, ctx):
             pre = "%s~%s." % (os.path.basename(ctx.path()), prefix)
             (fd, name) = tempfile.mkstemp(prefix=pre)
             data = repo.wwritedata(ctx.path(), ctx.data())
             f = os.fdopen(fd, "wb")
             f.write(data)
             f.close()
             return name
 
         if not fco.cmp(fcd): # files identical?
             return None
 
         ui = repo.ui
         fd = fcd.path()
         binary = fcd.isbinary() or fco.isbinary() or fca.isbinary()
         symlink = 'l' in fcd.flags() + fco.flags()
         tool, toolpath = _picktool(repo, ui, fd, binary, symlink)
         ui.debug("picked tool '%s' for %s (binary %s symlink %s)\n" %
                    (tool, fd, binary, symlink))
 
         if tool in internals:
             func = internals[tool]
             trymerge = func.trymerge
             onfailure = func.onfailure
         else:
             func = _xmerge
             trymerge = True
             onfailure = _("merging %s failed!\n")
 
         toolconf = tool, toolpath, binary, symlink
 
         if not trymerge:
             return func(repo, mynode, orig, fcd, fco, fca, toolconf)
 
         a = repo.wjoin(fd)
         b = temp("base", fca)
         c = temp("other", fco)
         back = a + ".orig"
         util.copyfile(a, back)
 
         if orig != fco.path():
             ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))
         else:
             ui.status(_("merging %s\n") % fd)
 
         ui.debug("my %s other %s ancestor %s\n" % (fcd, fco, fca))
 
         markerstyle = ui.config('ui', 'mergemarkers', 'basic')
         if not labels:
             labels = _defaultconflictlabels
         if markerstyle != 'basic':
             labels = _formatlabels(repo, fcd, fco, fca, labels)
 
         needcheck, r = func(repo, mynode, orig, fcd, fco, fca, toolconf,
                             (a, b, c, back), labels=labels)
         if not needcheck:
             if r:
                 if onfailure:
                     ui.warn(onfailure % fd)
             else:
                 util.unlink(back)
 
             util.unlink(b)
             util.unlink(c)
             return r
 
         if not r and (_toolbool(ui, tool, "checkconflicts") or
                       'conflicts' in _toollist(ui, tool, "check")):
             if re.search("^(<<<<<<< .*|=======|>>>>>>> .*)$", fcd.data(),
                          re.MULTILINE):
                 r = 1
 
         checked = False
         if 'prompt' in _toollist(ui, tool, "check"):
             checked = True
             if ui.promptchoice(_("was merge of '%s' successful (yn)?"
                                  "$$ &Yes $$ &No") % fd, 1):
                 r = 1
 
         if not r and not checked and (_toolbool(ui, tool, "checkchanged") or
                                       'changed' in
                                       _toollist(ui, tool, "check")):
             if filecmp.cmp(a, back):
                 if ui.promptchoice(_(" output file %s appears unchanged\n"
                                      "was merge successful (yn)?"
                                      "$$ &Yes $$ &No") % fd, 1):
                     r = 1
 
         if _toolbool(ui, tool, "fixeol"):
             _matcheol(a, back)
 
         if r:
             if onfailure:
                 ui.warn(onfailure % fd)
         else:
             util.unlink(back)
 
         util.unlink(b)
         util.unlink(c)
         return r
 
 # tell hggettext to extract docstrings from these functions:
 i18nfunctions = internals.values()