# HG changeset patch
# User Pulkit Goyal <7895pulkit@gmail.com>
# Date 1520945270 -19800
# Node ID d90e0faaec804f7e70527a82e59f0a568f38be98
# Parent  92f1e2408fd0eb680524f310fbc47342bc850a33
evolve: fix stabilization of orphan merge changesets in case of conflicts

As demonstrated by tests added in previous patch, if one of the parent of a
merge changeset has a new version and merge changeset gets, running `hg evolve`
to stabilize that if results in conflicts will lead to lose of other parent of
that merge changeset when we resolve conflicts and do `hg evolve --continue`.

This patch fixes the behavior, by checking whether we are continuing evolving a
merge changeset and if yes, setting the dirstate parents according to that.

diff -r 92f1e2408fd0 -r d90e0faaec80 hgext3rd/evolve/evolvecmd.py
--- a/hgext3rd/evolve/evolvecmd.py	Tue Mar 13 15:29:35 2018 +0530
+++ b/hgext3rd/evolve/evolvecmd.py	Tue Mar 13 18:17:50 2018 +0530
@@ -1134,6 +1134,34 @@
             targetphase = max(ctx.phase(), phases.draft)
             overrides = {('phases', 'new-commit'): targetphase}
 
+            ctxparents = orig.parents()
+            if len(ctxparents) == 2:
+                currentp1 = repo.dirstate.parents()[0]
+                p1obs = ctxparents[0].obsolete()
+                p2obs = ctxparents[1].obsolete()
+                # asumming that the parent of current wdir is successor of one
+                # of p1 or p2 of the original changeset
+                if p1obs and not p2obs:
+                    # p1 is obsolete and p2 is not obsolete, current working
+                    # directory parent should be successor of p1, so we should
+                    # set dirstate parents to (succ of p1, p2)
+                    with repo.dirstate.parentchange():
+                        repo.dirstate.setparents(currentp1,
+                                                 ctxparents[1].node())
+                elif p2obs and not p1obs:
+                    # p2 is obsolete and p1 is not obsolete, current working
+                    # directory parent should be successor of p2, so we should
+                    # set dirstate parents to (succ of p2, p1)
+                    with repo.dirstate.parentchange():
+                        repo.dirstate.setparents(currentp1,
+                                                 ctxparents[0].node())
+
+                else:
+                    # both the parents were obsolete, not sure what logic will
+                    # required here
+                    # XXX: add tests for this and see what is required here
+                    pass
+
             with repo.ui.configoverride(overrides, 'evolve-continue'):
                 node = repo.commit(text=message, user=user,
                                    date=date, extra=extra)
diff -r 92f1e2408fd0 -r d90e0faaec80 tests/test-evolve-orphan-merge.t
--- a/tests/test-evolve-orphan-merge.t	Tue Mar 13 15:29:35 2018 +0530
+++ b/tests/test-evolve-orphan-merge.t	Tue Mar 13 18:17:50 2018 +0530
@@ -230,47 +230,10 @@
   continue: hg evolve --continue
   $ hg evolve --continue
   evolving 10:fd41d25a3e90 "foobar to c"
-  working directory is now at 6b42180a13dd
-
-XXX: we lost the second parent here after interrupted evolve
-  $ hg glog
-  @  12:6b42180a13dd foobar to c
-  |   () draft
-  o  11:31c317b7bdb1 foo to c
-  |   () draft
-  | o  9:d0f84b25d4e3 bar to c
-  |/    () draft
-  o  0:8fa14d15e168 added hgignore
-      () draft
-
-  $ hg parents
-  changeset:   12:6b42180a13dd
-  tag:         tip
-  user:        test
-  date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     foobar to c
-  
-Getting back to a state from where we can test the same thing with obsoleting
-the second parent
-
-  $ hg prune -r .
-  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
-  working directory now at 31c317b7bdb1
-  1 changesets pruned
-  $ hg merge
-  merging c
-  warning: conflicts while merging c! (edit, then use 'hg resolve --mark')
-  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
-  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
-  [1]
-
-  $ echo FOObar > c
-  $ hg resolve -m
-  (no more unresolved files)
-  $ hg commit -m "FOObar to c"
+  working directory is now at c5405d2da7a1
 
   $ hg glog
-  @    13:14ac829917d7 FOObar to c
+  @    12:c5405d2da7a1 foobar to c
   |\    () draft
   | o  11:31c317b7bdb1 foo to c
   | |   () draft
@@ -279,6 +242,15 @@
   o  0:8fa14d15e168 added hgignore
       () draft
 
+  $ hg parents
+  changeset:   12:c5405d2da7a1
+  tag:         tip
+  parent:      11:31c317b7bdb1
+  parent:      9:d0f84b25d4e3
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foobar to c
+  
 Testing a conlficting merge with second parent obsoleted
 
   $ hg up 31c317b7bdb1
@@ -288,9 +260,9 @@
   1 new orphan changesets
 
   $ hg glog
-  @  14:928097d0b5b5 foo to c
+  @  13:928097d0b5b5 foo to c
   |   () draft
-  | *    13:14ac829917d7 FOObar to c
+  | *    12:c5405d2da7a1 foobar to c
   | |\    () draft
   +---x  11:31c317b7bdb1 foo to c
   | |     () draft
@@ -300,8 +272,8 @@
       () draft
 
   $ hg evolve --all
-  move:[13] FOObar to c
-  atop:[14] foo to c
+  move:[12] foobar to c
+  atop:[13] foo to c
   merging c
   warning: conflicts while merging c! (edit, then use 'hg resolve --mark')
   evolve failed!
@@ -315,16 +287,15 @@
   continue: hg evolve --continue
 
   $ hg evolve --continue
-  evolving 13:14ac829917d7 "FOObar to c"
-  working directory is now at 910c14950386
+  evolving 12:c5405d2da7a1 "foobar to c"
+  working directory is now at dc1948a6eeab
 
-XXX: we lost a parent here again.
   $ hg glog
-  @  15:910c14950386 FOObar to c
-  |   () draft
-  o  14:928097d0b5b5 foo to c
-  |   () draft
-  | o  9:d0f84b25d4e3 bar to c
+  @    14:dc1948a6eeab foobar to c
+  |\    () draft
+  | o  13:928097d0b5b5 foo to c
+  | |   () draft
+  o |  9:d0f84b25d4e3 bar to c
   |/    () draft
   o  0:8fa14d15e168 added hgignore
       () draft