# HG changeset patch
# User Sean Farley <sean.michael.farley@gmail.com>
# Date 1398473913 18000
# Node ID a94ce5400e1b8aaeb2fbce7f5a42bda219f83e8f
# Parent  6c5a6c2706f654bbdc1e16a904cbef2a27354a32
evolve: protect call to rebase within a wlock (#42, #35, #16)

Without a wlock, repo.commit would blow away the dirstate's parents on OSes
that have no 'os.symlink' support in python, leading evolve to produce a merge
instead of a rebase. If a user ran the rebase command instead of evolve, then
things would work because rebase is wrapped in a giant wlock.

Unfortunately, we can't use the same idea of wrapping the evolve command in one
giant wlock because that's too early in the process. If the lock did wrap the
entire evolve command, then the working directory would save its current
parents which, since rebase hasn't been called yet, would be just
p1.

Therefore, we need to obtain the lock *after* the dirstate's parents are
changed but *before* the call to rebase. This way ensures that when a conflict
happens the working directory correctly shows both parent changeset.

diff --git a/hgext/evolve.py b/hgext/evolve.py
--- a/hgext/evolve.py
+++ b/hgext/evolve.py
@@ -753,7 +753,10 @@
         destbookmarks = repo.nodebookmarks(dest.node())
         nodesrc = orig.node()
         destphase = repo[nodesrc].phase()
+        wlock = lock = None
         try:
+            wlock = repo.wlock()
+            lock = repo.lock()
             r = rebase.rebasenode(repo, orig.node(), dest.node(),
                                   {node.nullrev: node.nullrev}, False)
             if r[-1]: #some conflict
@@ -767,6 +770,8 @@
                 pass
             exc.__class__ = LocalMergeFailure
             raise
+        finally:
+            lockmod.release(lock, wlock)
         oldbookmarks = repo.nodebookmarks(nodesrc)
         if nodenew is not None:
             phases.retractboundary(repo, destphase, [nodenew])