rebase: introduce support for automatically rebasing orphan changes
authorAugie Fackler <augie@google.com>
Sun, 04 Mar 2018 15:29:41 -0500
changeset 37787 92213f6745ed
parent 37786 cc932c15b9ee
child 37788 ed5448edcbfa
child 37836 86e7a57449fa
rebase: introduce support for automatically rebasing orphan changes _destautorebase(SRC) is based on the _destrestack(SRC) revset from fbamend. The supporting _possibledestination function is extracted from evolve, with minor cleanups. We've considered some alternatives here: * This change, but with --auto as the flag name. We're hedging our bets on this a little in this change so that if this ends up being the wrong direction we haven't burned the valauble --auto name on rebase. * --destination auto: I've got reservations about the discoverability of this, and we don't currently have a good story for a revset alias of sorts that changes behavior depending on the context in which it's used. * A "rebase presets" feature, where we could use the currently-an-error positional argument space for the rebase command to define presets, so that users could define a 'linearize' preset that specifies --revision='orphan()-obsolete()' and --dest=_destautoorphanrebase(SRC). Personally, I find the third option somewhat appealing, but am hesitant to "spend" the functionality space of positional arguments to the rebase command. We should revisit the way we expose this functionality sometime in the 4.7 cycle once we've had a chance to vet the implementation of the functionality. Differential Revision: https://phab.mercurial-scm.org/D2668
hgext/rebase.py
mercurial/destutil.py
tests/test-rebase-obsolete.t
--- a/hgext/rebase.py	Wed Apr 18 14:32:36 2018 -0400
+++ b/hgext/rebase.py	Sun Mar 04 15:29:41 2018 -0500
@@ -108,6 +108,25 @@
         sourceset = revset.getset(repo, smartset.fullreposet(repo), x)
     return subset & smartset.baseset([_destrebase(repo, sourceset)])
 
+@revsetpredicate('_destautoorphanrebase')
+def _revsetdestautoorphanrebase(repo, subset, x):
+    """automatic rebase destination for a single orphan revision"""
+    unfi = repo.unfiltered()
+    obsoleted = unfi.revs('obsolete()')
+
+    src = revset.getset(repo, subset, x).first()
+
+    # Empty src or already obsoleted - Do not return a destination
+    if not src or src in obsoleted:
+        return smartset.baseset()
+    dests = destutil.orphanpossibledestination(repo, src)
+    if len(dests) > 1:
+        raise error.Abort(
+            _("ambiguous automatic rebase: %r could end up on any of %r") % (
+                src, dests))
+    # We have zero or one destination, so we can just return here.
+    return smartset.baseset(dests)
+
 def _ctxdesc(ctx):
     """short description for a context"""
     desc = '%d:%s "%s"' % (ctx.rev(), ctx,
@@ -651,7 +670,10 @@
     ('i', 'interactive', False, _('(DEPRECATED)')),
     ('t', 'tool', '', _('specify merge tool')),
     ('c', 'continue', False, _('continue an interrupted rebase')),
-    ('a', 'abort', False, _('abort an interrupted rebase'))] +
+    ('a', 'abort', False, _('abort an interrupted rebase')),
+    ('', 'auto-orphans', '', _('automatically rebase orphan revisions '
+                               'in the specified revset (EXPERIMENTAL)')),
+     ] +
     cmdutil.formatteropts,
     _('[-s REV | -b REV] [-d REV] [OPTION]'))
 def rebase(ui, repo, **opts):
@@ -783,6 +805,15 @@
         # fail the entire transaction.)
         inmemory = False
 
+    if opts.get('auto_orphans'):
+        for key in opts:
+            if key != 'auto_orphans' and opts.get(key):
+                raise error.Abort(_('--auto-orphans is incompatible with %s') %
+                                  ('--' + key))
+        userrevs = list(repo.revs(opts.get('auto_orphans')))
+        opts['rev'] = [revsetlang.formatspec('%ld and orphan()', userrevs)]
+        opts['dest'] = '_destautoorphanrebase(SRC)'
+
     if inmemory:
         try:
             # in-memory merge doesn't support conflicts, so if we hit any, abort
--- a/mercurial/destutil.py	Wed Apr 18 14:32:36 2018 -0400
+++ b/mercurial/destutil.py	Sun Mar 04 15:29:41 2018 -0500
@@ -16,6 +16,39 @@
     stack
 )
 
+def orphanpossibledestination(repo, rev):
+    """Return all changesets that may be a new parent for orphan `rev`.
+
+    This function works fine on non-orphan revisions, it's just silly
+    because there's no destination implied by obsolete markers, so
+    it'll return nothing.
+    """
+    tonode = repo.changelog.node
+    parents = repo.changelog.parentrevs
+    torev = repo.changelog.rev
+    dest = set()
+    tovisit = list(parents(rev))
+    while tovisit:
+        r = tovisit.pop()
+        succsets = obsutil.successorssets(repo, tonode(r))
+        if not succsets:
+            # if there are no successors for r, r was probably pruned
+            # and we should walk up to r's parents to try and find
+            # some successors.
+            tovisit.extend(parents(r))
+        else:
+            # We should probably pick only one destination from split
+            # (case where '1 < len(ss)'), This could be the currently
+            # tipmost, but the correct result is less clear when
+            # results of the split have been moved such that they
+            # reside on multiple branches.
+            for ss in succsets:
+                for n in ss:
+                    dr = torev(n)
+                    if dr != -1:
+                        dest.add(dr)
+    return dest
+
 def _destupdateobs(repo, clean):
     """decide of an update destination from obsolescence markers"""
     node = None
--- a/tests/test-rebase-obsolete.t	Wed Apr 18 14:32:36 2018 -0400
+++ b/tests/test-rebase-obsolete.t	Sun Mar 04 15:29:41 2018 -0500
@@ -482,7 +482,34 @@
   |/
   o  0:cd010b8cd998 A
   
+  $ cd ..
+  $ cp -R hidden stabilize
+  $ cd stabilize
+  $ hg rebase --auto-orphans '0::' -d 10
+  abort: --auto-orphans is incompatible with --dest
+  [255]
+  $ hg rebase --auto-orphans '0::'
+  rebasing 9:cf44d2f5a9f4 "D"
+  $ hg log -G
+  o  12:7e3935feaa68 D
+  |
+  o  11:0d8f238b634c C
+  |
+  o  10:7c6027df6a99 B
+  |
+  @  7:02de42196ebe H
+  |
+  | o  6:eea13746799a G
+  |/|
+  o |  5:24b6387c8c8c F
+  | |
+  | o  4:9520eea781bc E
+  |/
+  o  0:cd010b8cd998 A
+  
 
+  $ cd ../hidden
+  $ rm -r ../stabilize
 
 Test multiple root handling
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