uncommit: unify functions _uncommitdirstate and _unamenddirstate to one

The _unamenddirstate() function was inspired by _uncommitdirstate() function as
the logic was same but we were unable to use the latter function directly. So
previous patch introduced the _unamenddirstate() function and now this patch
unifies both the function and we have a _fixdirstate() function.

Adding function in previous patch and unifying in a later patch makes the
reasoning easier and also leaves the last patch dedicated to what it is meant to
be.

Differential Revision: https://phab.mercurial-scm.org/D971

hgext/uncommit.py

@@ -1,318 +1,277 b''
 # uncommit - undo the actions of a commit
 #
 # Copyright 2011 Peter Arrenbrecht <[e-mail]>
 #                Logilab SA        <[e-mail]>
 #                Pierre-Yves David <[e-mail]>
 #                Patrick Mezard <[e-mail]>
 # Copyright 2016 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """uncommit part or all of a local changeset (EXPERIMENTAL)
 
 This command undoes the effect of a local commit, returning the affected
 files to their uncommitted state. This means that files modified, added or
 removed in the changeset will be left unchanged, and so will remain modified,
 added and removed in the working directory.
 """
 
 from __future__ import absolute_import
 
 from mercurial.i18n import _
 
 from mercurial import (
     cmdutil,
     commands,
     context,
     copies,
     error,
     node,
     obsolete,
     obsutil,
     pycompat,
     registrar,
     scmutil,
 )
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 configitem('experimental', 'uncommitondirtywdir',
     default=False,
 )
 
 # 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'
 
 def _commitfiltered(repo, ctx, match, allowempty):
     """Recommit ctx with changed files not in match. Return the new
     node identifier, or None if nothing changed.
     """
     base = ctx.p1()
     # ctx
     initialfiles = set(ctx.files())
     exclude = set(f for f in initialfiles if match(f))
 
     # No files matched commit, so nothing excluded
     if not exclude:
         return None
 
     files = (initialfiles - exclude)
     # return the p1 so that we don't create an obsmarker later
     if not files and not allowempty:
         return ctx.parents()[0].node()
 
     # Filter copies
     copied = copies.pathcopies(base, ctx)
     copied = dict((dst, src) for dst, src in copied.iteritems()
                   if dst in files)
     def filectxfn(repo, memctx, path, contentctx=ctx, redirect=()):
         if path not in contentctx:
             return None
         fctx = contentctx[path]
         mctx = context.memfilectx(repo, fctx.path(), fctx.data(),
                                   fctx.islink(),
                                   fctx.isexec(),
                                   copied=copied.get(path))
         return mctx
 
     new = context.memctx(repo,
                          parents=[base.node(), node.nullid],
                          text=ctx.description(),
                          files=files,
                          filectxfn=filectxfn,
                          user=ctx.user(),
                          date=ctx.date(),
                          extra=ctx.extra())
     # phase handling
     commitphase = ctx.phase()
     overrides = {('phases', 'new-commit'): commitphase}
     with repo.ui.configoverride(overrides, 'uncommit'):
         newid = repo.commitctx(new)
     return newid
 
-def _uncommitdirstate(repo, oldctx, match):
-    """Fix the dirstate after switching the working directory from
-    oldctx to a copy of oldctx not containing changed files matched by
-    match.
+def _fixdirstate(repo, oldctx, newctx, status):
+    """ fix the dirstate after switching the working directory from oldctx to
+    newctx which can be result of either unamend or uncommit.
     """
-    ctx = repo['.']
     ds = repo.dirstate
     copies = dict(ds.copies())
-    s = repo.status(oldctx.p1(), oldctx, match=match)
+    s = status
     for f in s.modified:
         if ds[f] == 'r':
             # modified + removed -> removed
             continue
         ds.normallookup(f)
 
     for f in s.added:
         if ds[f] == 'r':
             # added + removed -> unknown
             ds.drop(f)
         elif ds[f] != 'a':
             ds.add(f)
 
     for f in s.removed:
         if ds[f] == 'a':
             # removed + added -> normal
             ds.normallookup(f)
         elif ds[f] != 'r':
             ds.remove(f)
 
     # Merge old parent and old working dir copies
     oldcopies = {}
     for f in (s.modified + s.added):
         src = oldctx[f].renamed()
         if src:
             oldcopies[f] = src[0]
     oldcopies.update(copies)
     copies = dict((dst, oldcopies.get(src, src))
                   for dst, src in oldcopies.iteritems())
     # Adjust the dirstate copies
     for dst, src in copies.iteritems():
-        if (src not in ctx or dst in ctx or ds[dst] != 'a'):
+        if (src not in newctx or dst in newctx or ds[dst] != 'a'):
             src = None
         ds.copy(src, dst)
 
 @command('uncommit',
     [('', 'keep', False, _('allow an empty commit after uncommiting')),
     ] + commands.walkopts,
     _('[OPTION]... [FILE]...'))
 def uncommit(ui, repo, *pats, **opts):
     """uncommit part or all of a local changeset
 
     This command undoes the effect of a local commit, returning the affected
     files to their uncommitted state. This means that files modified or
     deleted in the changeset will be left unchanged, and so will remain
     modified in the working directory.
     """
     opts = pycompat.byteskwargs(opts)
 
     with repo.wlock(), repo.lock():
         wctx = repo[None]
 
         if not pats and not repo.ui.configbool('experimental',
                                                 'uncommitondirtywdir'):
             cmdutil.bailifchanged(repo)
         if wctx.parents()[0].node() == node.nullid:
             raise error.Abort(_("cannot uncommit null changeset"))
         if len(wctx.parents()) > 1:
             raise error.Abort(_("cannot uncommit while merging"))
         old = repo['.']
         if not old.mutable():
             raise error.Abort(_('cannot uncommit public changesets'))
         if len(old.parents()) > 1:
             raise error.Abort(_("cannot uncommit merge changeset"))
         allowunstable = obsolete.isenabled(repo, obsolete.allowunstableopt)
         if not allowunstable and old.children():
             raise error.Abort(_('cannot uncommit changeset with children'))
 
         with repo.transaction('uncommit'):
             match = scmutil.match(old, pats, opts)
             newid = _commitfiltered(repo, old, match, opts.get('keep'))
             if newid is None:
                 ui.status(_("nothing to uncommit\n"))
                 return 1
 
             mapping = {}
             if newid != old.p1().node():
                 # Move local changes on filtered changeset
                 mapping[old.node()] = (newid,)
             else:
                 # Fully removed the old commit
                 mapping[old.node()] = ()
 
             scmutil.cleanupnodes(repo, mapping, 'uncommit')
 
             with repo.dirstate.parentchange():
                 repo.dirstate.setparents(newid, node.nullid)
-                _uncommitdirstate(repo, old, match)
+                s = repo.status(old.p1(), old, match=match)
+                _fixdirstate(repo, old, repo[newid], s)
 
 def predecessormarkers(ctx):
     """yields the obsolete markers marking the given changeset as a successor"""
     for data in ctx.repo().obsstore.predecessors.get(ctx.node(), ()):
         yield obsutil.marker(ctx.repo(), data)
 
-def _unamenddirstate(repo, predctx, curctx):
-    """"""
-
-    s = repo.status(predctx, curctx)
-    ds = repo.dirstate
-    copies = dict(ds.copies())
-    for f in s.modified:
-        if ds[f] == 'r':
-            # modified + removed -> removed
-            continue
-        ds.normallookup(f)
-
-    for f in s.added:
-        if ds[f] == 'r':
-            # added + removed -> unknown
-            ds.drop(f)
-        elif ds[f] != 'a':
-            ds.add(f)
-
-    for f in s.removed:
-        if ds[f] == 'a':
-            # removed + added -> normal
-            ds.normallookup(f)
-        elif ds[f] != 'r':
-            ds.remove(f)
-
-    # Merge old parent and old working dir copies
-    oldcopies = {}
-    for f in (s.modified + s.added):
-        src = curctx[f].renamed()
-        if src:
-            oldcopies[f] = src[0]
-    oldcopies.update(copies)
-    copies = dict((dst, oldcopies.get(src, src))
-                  for dst, src in oldcopies.iteritems())
-    # Adjust the dirstate copies
-    for dst, src in copies.iteritems():
-        if (src not in predctx or dst in predctx or ds[dst] != 'a'):
-            src = None
-        ds.copy(src, dst)
-
 @command('^unamend', [])
 def unamend(ui, repo, **opts):
     """
     undo the most recent amend operation on a current changeset
 
     This command will roll back to the previous version of a changeset,
     leaving working directory in state in which it was before running
     `hg amend` (e.g. files modified as part of an amend will be
     marked as modified `hg status`)
     """
 
     unfi = repo.unfiltered()
 
     # identify the commit from which to unamend
     curctx = repo['.']
 
     with repo.wlock(), repo.lock(), repo.transaction('unamend'):
         if not curctx.mutable():
             raise error.Abort(_('cannot unamend public changesets'))
 
         # identify the commit to which to unamend
         markers = list(predecessormarkers(curctx))
         if len(markers) != 1:
             e = _("changeset must have one predecessor, found %i predecessors")
             raise error.Abort(e % len(markers))
 
         prednode = markers[0].prednode()
         predctx = unfi[prednode]
 
         if curctx.children():
             raise error.Abort(_("cannot unamend a changeset with children"))
 
         # add an extra so that we get a new hash
         # note: allowing unamend to undo an unamend is an intentional feature
         extras = predctx.extra()
         extras['unamend_source'] = curctx.node()
 
         def filectxfn(repo, ctx_, path):
             try:
                 return predctx.filectx(path)
             except KeyError:
                 return None
 
         # Make a new commit same as predctx
         newctx = context.memctx(repo,
                                 parents=(predctx.p1(), predctx.p2()),
                                 text=predctx.description(),
                                 files=predctx.files(),
                                 filectxfn=filectxfn,
                                 user=predctx.user(),
                                 date=predctx.date(),
                                 extra=extras)
         # phase handling
         commitphase = curctx.phase()
         overrides = {('phases', 'new-commit'): commitphase}
         with repo.ui.configoverride(overrides, 'uncommit'):
             newprednode = repo.commitctx(newctx)
 
         newpredctx = repo[newprednode]
 
         changedfiles = []
         wctx = repo[None]
         wm = wctx.manifest()
         cm = newpredctx.manifest()
         dirstate = repo.dirstate
         diff = cm.diff(wm)
         changedfiles.extend(diff.iterkeys())
 
         with dirstate.parentchange():
             dirstate.setparents(newprednode, node.nullid)
-            _unamenddirstate(repo, newpredctx, curctx)
+            s = repo.status(predctx, curctx)
+            _fixdirstate(repo, curctx, newpredctx, s)
 
         mapping = {curctx.node(): (newprednode,)}
         scmutil.cleanupnodes(repo, mapping, 'unamend')