prepush: backed out refactoring

prepush: backed out refactoring

It has some problems in corner cases and will fail on a test recently
introduced on stable. Will maybe be reintroduced later, in a better
version.

--- a/mercurial/localrepo.py	Thu Apr 08 17:21:42 2010 +0200
+++ b/mercurial/localrepo.py	Wed Apr 14 19:43:19 2010 +0200
@@ -1500,13 +1500,8 @@
         remote_heads = remote.heads()
         inc = self.findincoming(remote, common, remote_heads, force=force)
 
-        cl = self.changelog
         update, updated_heads = self.findoutgoing(remote, common, remote_heads)
-        msng_cl, bases, heads = cl.nodesbetween(update, revs)
-
-        outgoingnodeset = set(msng_cl)
-        # compute set of nodes which, if they were a head before, no longer are
-        nolongeraheadnodeset = set(p for n in msng_cl for p in cl.parents(n))
+        msng_cl, bases, heads = self.changelog.nodesbetween(update, revs)
 
         def checkbranch(lheads, rheads, branchname=None):
             '''
@@ -1516,10 +1511,33 @@
             lheads: local branch heads
             rheads: remote branch heads
             '''
-            newlheads = [n for n in lheads if n in outgoingnodeset]
-            formerrheads = [n for n in rheads if n in nolongeraheadnodeset]
-            if len(newlheads) > len(formerrheads):
-                # we add more new heads than we demote former heads to non-head
+
+            warn = 0
+
+            if len(lheads) > len(rheads):
+                warn = 1
+            else:
+                # add local heads involved in the push
+                updatelheads = [self.changelog.heads(x, lheads)
+                                for x in update]
+                newheads = set(sum(updatelheads, [])) & set(lheads)
+
+                if not newheads:
+                    return True
+
+                # add heads we don't have or that are not involved in the push
+                for r in rheads:
+                    if r in self.changelog.nodemap:
+                        desc = self.changelog.heads(r, heads)
+                        l = [h for h in heads if h in desc]
+                        if not l:
+                            newheads.add(r)
+                    else:
+                        newheads.add(r)
+                if len(newheads) > len(rheads):
+                    warn = 1
+
+            if warn:
                 if branchname is not None:
                     msg = _("abort: push creates new remote heads"
                             " on branch '%s'!\n") % branchname
@@ -1583,7 +1601,7 @@
 
         if revs is None:
             # use the fast path, no race possible on push
-            nodes = cl.findmissing(common.keys())
+            nodes = self.changelog.findmissing(common.keys())
             cg = self._changegroup(nodes, 'push')
         else:
             cg = self.changegroupsubset(update, revs, 'push')