# HG changeset patch
# User Juntao Li <juntaoli@fb.com>
# Date 1458259431 25200
# Node ID 498329a3c90048f5c211dabcfaab1bfc7bdbd3fa
# Parent  d49f4ad04fbdeb62a5ce97ebf9f3a77946604b8a
evolve: Fix crash when reading docstring

Before this patch, hg evolve --divergent could crash when looking
for docstring of function of merge.update. We were checking the
docstring to work properly with older version of Mercurial. It
could crash if an extension would wrap merge.update without
keeping the docstring. This patch fixes the crash.

diff -r d49f4ad04fbd -r 498329a3c900 hgext/evolve.py
--- a/hgext/evolve.py	Sat Mar 12 13:15:28 2016 +0800
+++ b/hgext/evolve.py	Thu Mar 17 17:03:51 2016 -0700
@@ -1998,7 +1998,14 @@
         hg.update(repo, divergent.rev())
     repo.ui.note(_('merging divergent changeset\n'))
     if progresscb: progresscb()
-    if 'partial' in merge.update.__doc__:
+    try:
+        stats = merge.update(repo,
+                             other.node(),
+                             branchmerge=True,
+                             force=False,
+                             ancestor=base.node(),
+                             mergeancestor=True)
+    except TypeError:
         # Mercurial  < 43c00ca887d1 (3.7)
         stats = merge.update(repo,
                              other.node(),
@@ -2007,13 +2014,6 @@
                              partial=None,
                              ancestor=base.node(),
                              mergeancestor=True)
-    else:
-        stats = merge.update(repo,
-                             other.node(),
-                             branchmerge=True,
-                             force=False,
-                             ancestor=base.node(),
-                             mergeancestor=True)
 
     hg._showstats(repo, stats)
     if stats[3]:
diff -r d49f4ad04fbd -r 498329a3c900 tests/test-divergent.t
--- a/tests/test-divergent.t	Sat Mar 12 13:15:28 2016 +0800
+++ b/tests/test-divergent.t	Thu Mar 17 17:03:51 2016 -0700
@@ -107,5 +107,53 @@
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   working directory is now at 6602ff5a79dc
- 
-  $ cd ..  
+
+Test None docstring issue of evolve divergent, which caused hg crush
+
+  $ hg init test2
+  $ cd test2
+  $ mkcommits _a _b
+  $ hg up "desc(_a)"
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit bdivergent1
+  created new head
+  $ hg up "desc(_a)"
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit bdivergent2
+  created new head
+  $ hg prune -s "desc(bdivergent1)" "desc(_b)"
+  1 changesets pruned
+  $ hg prune -s "desc(bdivergent2)" "desc(_b)" --hidden
+  1 changesets pruned
+  2 new divergent changesets
+  $ hg log -G
+  @  3:e708fd28d5cf@default(draft) add bdivergent2 [divergent]
+  |
+  | o  2:c2f698071cba@default(draft) add bdivergent1 [divergent]
+  |/
+  o  0:135f39f4bd78@default(draft) add _a []
+  
+  $ cat >$TESTTMP/test_extension.py  << EOF
+  > from mercurial import merge
+  > origupdate = merge.update
+  > def newupdate(*args, **kwargs):
+  >   return origupdate(*args, **kwargs)
+  > merge.update = newupdate
+  > EOF
+  $ cat >> $HGRCPATH << EOF
+  > [extensions]
+  > testextension=$TESTTMP/test_extension.py
+  > EOF
+  $ hg evolve --all
+  nothing to evolve on current working copy parent
+  (do you want to use --divergent)
+  [2]
+  $ hg evolve --divergent
+  merge:[3] add bdivergent2
+  with: [2] add bdivergent1
+  base: [1] add _b
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  working directory is now at aa26817f6fbe
+
+
+  $ cd ..