hgext/split.py
changeset 35455 02ea370c2baa
child 36400 7b86aa31b004
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/split.py	Sat Jun 24 23:03:41 2017 -0700
@@ -0,0 +1,177 @@
+# split.py - split a changeset into smaller ones
+#
+# Copyright 2015 Laurent Charignon <lcharignon@fb.com>
+# Copyright 2017 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.
+"""command to split a changeset into smaller ones (EXPERIMENTAL)"""
+
+from __future__ import absolute_import
+
+from mercurial.i18n import _
+
+from mercurial.node import (
+    nullid,
+    short,
+)
+
+from mercurial import (
+    bookmarks,
+    cmdutil,
+    commands,
+    error,
+    hg,
+    obsolete,
+    phases,
+    registrar,
+    revsetlang,
+    scmutil,
+)
+
+# allow people to use split without explicitly enabling rebase extension
+from . import (
+    rebase,
+)
+
+cmdtable = {}
+command = registrar.command(cmdtable)
+
+# 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'
+
+@command('^split',
+    [('r', 'rev', '', _("revision to split"), _('REV')),
+     ('', 'rebase', True, _('rebase descendants after split')),
+    ] + cmdutil.commitopts2,
+    _('hg split [--no-rebase] [[-r] REV]'))
+def split(ui, repo, *revs, **opts):
+    """split a changeset into smaller ones
+
+    Repeatedly prompt changes and commit message for new changesets until there
+    is nothing left in the original changeset.
+
+    If --rev was not given, split the working directory parent.
+
+    By default, rebase connected non-obsoleted descendants onto the new
+    changeset. Use --no-rebase to avoid the rebase.
+    """
+    revlist = []
+    if opts.get('rev'):
+        revlist.append(opts.get('rev'))
+    revlist.extend(revs)
+    with repo.wlock(), repo.lock(), repo.transaction('split') as tr:
+        revs = scmutil.revrange(repo, revlist or ['.'])
+        if len(revs) > 1:
+            raise error.Abort(_('cannot split multiple revisions'))
+
+        rev = revs.first()
+        ctx = repo[rev]
+        if rev is None or ctx.node() == nullid:
+            ui.status(_('nothing to split\n'))
+            return 1
+        if ctx.node() is None:
+            raise error.Abort(_('cannot split working directory'))
+
+        # rewriteutil.precheck is not very useful here because:
+        # 1. null check is done above and it's more friendly to return 1
+        #    instead of abort
+        # 2. mergestate check is done below by cmdutil.bailifchanged
+        # 3. unstable check is more complex here because of --rebase
+        #
+        # So only "public" check is useful and it's checked directly here.
+        if ctx.phase() == phases.public:
+            raise error.Abort(_('cannot split public changeset'),
+                              hint=_("see 'hg help phases' for details"))
+
+        descendants = list(repo.revs('(%d::) - (%d)', rev, rev))
+        alloworphaned = obsolete.isenabled(repo, obsolete.allowunstableopt)
+        if opts.get('rebase'):
+            # Skip obsoleted descendants and their descendants so the rebase
+            # won't cause conflicts for sure.
+            torebase = list(repo.revs('%ld - (%ld & obsolete())::',
+                                      descendants, descendants))
+            if not alloworphaned and len(torebase) != len(descendants):
+                raise error.Abort(_('split would leave orphaned changesets '
+                                    'behind'))
+        else:
+            if not alloworphaned and descendants:
+                raise error.Abort(
+                    _('cannot split changeset with children without rebase'))
+            torebase = ()
+
+        if len(ctx.parents()) > 1:
+            raise error.Abort(_('cannot split a merge changeset'))
+
+        cmdutil.bailifchanged(repo)
+
+        # Deactivate bookmark temporarily so it won't get moved unintentionally
+        bname = repo._activebookmark
+        if bname and repo._bookmarks[bname] != ctx.node():
+            bookmarks.deactivate(repo)
+
+        wnode = repo['.'].node()
+        top = None
+        try:
+            top = dosplit(ui, repo, tr, ctx, opts)
+        finally:
+            # top is None: split failed, need update --clean recovery.
+            # wnode == ctx.node(): wnode split, no need to update.
+            if top is None or wnode != ctx.node():
+                hg.clean(repo, wnode, show_stats=False)
+            if bname:
+                bookmarks.activate(repo, bname)
+        if torebase and top:
+            dorebase(ui, repo, torebase, top)
+
+def dosplit(ui, repo, tr, ctx, opts):
+    committed = [] # [ctx]
+
+    # Set working parent to ctx.p1(), and keep working copy as ctx's content
+    # NOTE: if we can have "update without touching working copy" API, the
+    # revert step could be cheaper.
+    hg.clean(repo, ctx.p1().node(), show_stats=False)
+    parents = repo.changelog.parents(ctx.node())
+    ui.pushbuffer()
+    cmdutil.revert(ui, repo, ctx, parents)
+    ui.popbuffer() # discard "reverting ..." messages
+
+    # Any modified, added, removed, deleted result means split is incomplete
+    incomplete = lambda repo: any(repo.status()[:4])
+
+    # Main split loop
+    while incomplete(repo):
+        if committed:
+            header = (_('HG: Splitting %s. So far it has been split into:\n')
+                      % short(ctx.node()))
+            for c in committed:
+                firstline = c.description().split('\n', 1)[0]
+                header += _('HG: - %s: %s\n') % (short(c.node()), firstline)
+            header += _('HG: Write commit message for the next split '
+                        'changeset.\n')
+        else:
+            header = _('HG: Splitting %s. Write commit message for the '
+                       'first split changeset.\n') % short(ctx.node())
+        opts.update({
+            'edit': True,
+            'interactive': True,
+            'message': header + ctx.description(),
+        })
+        commands.commit(ui, repo, **opts)
+        newctx = repo['.']
+        committed.append(newctx)
+
+    if not committed:
+        raise error.Abort(_('cannot split an empty revision'))
+
+    scmutil.cleanupnodes(repo, {ctx.node(): [c.node() for c in committed]},
+                         operation='split')
+
+    return committed[-1]
+
+def dorebase(ui, repo, src, dest):
+    rebase.rebase(ui, repo, rev=[revsetlang.formatspec('%ld', src)],
+                  dest=revsetlang.formatspec('%d', dest))