# HG changeset patch
# User Pulkit Goyal <7895pulkit@gmail.com>
# Date 1497736426 -19800
# Node ID fd602980f7eee3ae86e8d0d9c44fc7c1539d8700
# Parent  a263f4c0f2ee28bf51aa3852c0d6813c80eb9690
topics: make sure we commit on new parents while changing topics (issue5441)

While changing topics of a set of linear commits, we used to commit our new
changesets with new topic on parents of its predecessor i.e. changeset before
the topic change. If the topic of parent was also changed, that parent will
become obsolete and hence resulting the cnew commit in unstable state. For a set
of linear commits this repeats and we end up in a tree state as mentioned in the
bug.

This patch fixes the bug by checking whether the parent was obsoleted and if
yes, commit on the new parent.

diff -r a263f4c0f2ee -r fd602980f7ee README
--- a/README	Sun Jun 18 03:20:52 2017 +0530
+++ b/README	Sun Jun 18 03:23:46 2017 +0530
@@ -121,6 +121,11 @@
 Changelog
 =========
 
+6.5.0 - in progress
+-------------------
+
+ - topic: fix issue5441 in the linear case,
+
 6.4.0 -- 2017-06-16
 -------------------
 
diff -r a263f4c0f2ee -r fd602980f7ee hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Sun Jun 18 03:20:52 2017 +0530
+++ b/hgext3rd/topic/__init__.py	Sun Jun 18 03:23:46 2017 +0530
@@ -282,6 +282,10 @@
         l = repo.lock()
         txn = repo.transaction('rewrite-topics')
         try:
+            newp = None
+            oldp = None
+            p1 = None
+            p2 = None
             for c in repo.set('%r', change):
                 def filectxfn(repo, ctx, path):
                     try:
@@ -309,11 +313,25 @@
                 ui.debug('changing topic of %s from %s to %s\n' % (
                     c, oldtopic, newtopic))
                 ui.debug('fixedextra: %r\n' % fixedextra)
+                # While changing topic of set of linear commits, make sure that
+                # we base our commits on new parent rather than old parent which
+                # was obsoleted while changing the topic
+                if newp and c.p1().node() == oldp:
+                    p1 = newp
+                    p2 = c.p2().node()
+                elif newp and c.p2().node() == oldp:
+                    p1 = c.p1().node()
+                    p2 = newp
+                else:
+                    p1 = c.p1().node()
+                    p2 = c.p2().node()
                 mc = context.memctx(
-                    repo, (c.p1().node(), c.p2().node()), c.description(),
+                    repo, (p1, p2), c.description(),
                     c.files(), filectxfn,
                     user=c.user(), date=c.date(), extra=fixedextra)
                 newnode = repo.commitctx(mc)
+                oldp = c.node()
+                newp = newnode
                 ui.debug('new node id is %s\n' % node.hex(newnode))
                 needevolve = needevolve or (len(c.children()) > 0)
                 obsolete.createmarkers(repo, [(c, (repo[newnode],))])
diff -r a263f4c0f2ee -r fd602980f7ee tests/test-topic.t
--- a/tests/test-topic.t	Sun Jun 18 03:20:52 2017 +0530
+++ b/tests/test-topic.t	Sun Jun 18 03:23:46 2017 +0530
@@ -679,30 +679,28 @@
   changed topic on 2 changes
   please run hg evolve --rev "topic(changewat)" now
   $ hg log -Gr 'draft()'
-  o  changeset:   21:3c7d84fcabcd
+  o  changeset:   21:58e15a6365ca
   |  tag:         tip
   |  topic:       changewat
-  |  parent:      13:d91cd8fd490e
   |  user:        test
   |  date:        Thu Jan 01 00:00:00 1970 +0000
-  |  trouble:     unstable
   |  summary:     fran?
   |
-  | o  changeset:   20:a96ac830b62e
-  | |  topic:       changewat
-  | |  parent:      3:a53952faf762
+  o  changeset:   20:a96ac830b62e
+  |  topic:       changewat
+  |  parent:      3:a53952faf762
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     start on fran
+  |
+  | @  changeset:   19:b72b86a1f96b
+  | |  topic:       watwat
+  | |  parent:      13:d91cd8fd490e
   | |  user:        test
   | |  date:        Thu Jan 01 00:00:00 1970 +0000
-  | |  summary:     start on fran
+  | |  summary:     fran?
   | |
-  +---@  changeset:   19:b72b86a1f96b
-  | |    topic:       watwat
-  | |    parent:      13:d91cd8fd490e
-  | |    user:        test
-  | |    date:        Thu Jan 01 00:00:00 1970 +0000
-  | |    summary:     fran?
-  | |
-  x |  changeset:   13:d91cd8fd490e
+  | x  changeset:   13:d91cd8fd490e
   |/   topic:       wat
   |    parent:      3:a53952faf762
   |    user:        test