# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1435026261 25200
# Node ID 0b714c4ad9ff89f917d0d43364fbbe498b4917b6
# Parent  b54524ae77c00e38a308b4b4fadf5353aafa9bac
evolve: consider all potential candidates on bare evolve

Instead of stopping at the first resolution, we returns all matches. If there is
ambiguity, we abort.

The function itself seems fairly flawed but will do the job in simple case.

diff -r b54524ae77c0 -r 0b714c4ad9ff README
--- a/README	Tue Jun 23 13:20:00 2015 -0700
+++ b/README	Mon Jun 22 19:24:21 2015 -0700
@@ -58,7 +58,9 @@
 - evolve: properly skip unstable revision with non-evolved unstable parent
 - evolve: gain --unstable --divergent --bumped flag to select the trouble
 - evolve: issue more useful error message and hint when evolve has nothing to
-  do as invocated.
+          do as invocated.
+- evolve: bare `hg evolve` commands now abort when multiple changesets could be
+          a target.
 
 5.1.5 --
 
diff -r b54524ae77c0 -r 0b714c4ad9ff hgext/evolve.py
--- a/hgext/evolve.py	Tue Jun 23 13:20:00 2015 -0700
+++ b/hgext/evolve.py	Mon Jun 22 19:24:21 2015 -0700
@@ -1410,9 +1410,12 @@
     elif anyopt:
         revs = repo.revs('first(%s())' % (targetcat))
     elif targetcat == 'unstable':
-        tro = _stabilizableunstable(repo, repo['.'])
-        if tro is not None:
-            revs = set([tro])
+        revs = set(_aspiringchildren(repo, repo['.']))
+        if 1 < len(revs):
+            msg = "multiple evolve candidates"
+            hint = (_("select one of %s with --rev")
+                    % ', '.join([str(repo[r]) for r in sorted(revs)]))
+            raise error.Abort(msg, hint=hint)
     elif targetcat in repo['.'].troubles():
         revs = set([repo['.'].rev()])
     return revs
@@ -1586,10 +1589,9 @@
     progresscb()
     _cleanup(ui, repo, startnode, showprogress)
 
-def _stabilizableunstable(repo, pctx):
-    """Return a changectx for an unstable changeset which can be
-    stabilized on top of pctx or one of its descendants. None if none
-    can be found.
+def _aspiringchildren(repo, pctx):
+    """Return a list of changectx which can be stabilized on top of pctx or
+    one of its descendants. Empty list if none can be found.
     """
     def selfanddescendants(repo, pctx):
         yield pctx
@@ -1602,14 +1604,15 @@
 
     # Look for an unstable which can be stabilized as a child of
     # node. The unstable must be a child of one of node predecessors.
+    result = []
     directdesc = set([pctx.rev()])
     for ctx in selfanddescendants(repo, pctx):
         for child in ctx.children():
             if ctx.rev() in directdesc and not child.obsolete():
                 directdesc.add(child.rev())
             elif child.unstable():
-                return child
-    return None
+                result.append(child)
+    return result
 
 def _solveunstable(ui, repo, orig, dryrun=False, confirm=False,
                    progresscb=None):
diff -r b54524ae77c0 -r 0b714c4ad9ff tests/test-stabilize-order.t
--- a/tests/test-stabilize-order.t	Tue Jun 23 13:20:00 2015 -0700
+++ b/tests/test-stabilize-order.t	Mon Jun 22 19:24:21 2015 -0700
@@ -182,3 +182,66 @@
   $ hg evolve --any -v
   no unstable changesets to evolve
   [1]
+
+Ambiguous evolution
+  $ echo a > k
+  $ hg add k
+  $ hg ci -m firstambiguous
+  $ hg up .^
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo a > l
+  $ hg add l
+  $ hg ci -m secondambiguous
+  created new head
+  $ hg up .^
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg commit --amend -m "newmessage"
+  2 new unstable changesets
+  $ hg log -G
+  @  changeset:   15:49773ccde390
+  |  tag:         tip
+  |  parent:      11:036cf654e942
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     newmessage
+  |
+  | o  changeset:   14:a9892777b519
+  | |  parent:      12:e99ecf51c867
+  | |  user:        test
+  | |  date:        Thu Jan 01 00:00:00 1970 +0000
+  | |  summary:     secondambiguous
+  | |
+  | | o  changeset:   13:0b6e26b2472d
+  | |/   user:        test
+  | |    date:        Thu Jan 01 00:00:00 1970 +0000
+  | |    summary:     firstambiguous
+  | |
+  | x  changeset:   12:e99ecf51c867
+  |/   user:        test
+  |    date:        Thu Jan 01 00:00:00 1970 +0000
+  |    summary:     addc
+  |
+  o  changeset:   11:036cf654e942
+  |  parent:      7:005fe5914f78
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     addb
+  |
+  o  changeset:   7:005fe5914f78
+  |  parent:      0:c471ef929e6a
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     adda
+  |
+  o  changeset:   0:c471ef929e6a
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     addroot
+  
+  $ hg evolve
+  abort: multiple evolve candidates
+  (select one of *, * with --rev) (glob)
+  [255]
+
+
+