revset: add support for ancestors(wdir())

This is a part of extending support for wdir() predicate.

mercurial/revset.py

@@ -75,9 +75,14 b' def _revancestors(repo, revs, followfirs'
             if current not in seen:
                 seen.add(current)
                 yield current
+                try:
                 for parent in cl.parentrevs(current)[:cut]:
                     if parent != node.nullrev:
                         heapq.heappush(h, -parent)
+                except error.WdirUnsupported:
+                    for parent in repo[current].parents()[:cut]:
+                        if parent.rev() != node.nullrev:
+                            heapq.heappush(h, -parent.rev())
 
     return generatorset(iterate(), iterasc=False)
 

tests/test-revset.t

@@ -1231,6 +1231,16 b' Test working-directory revision'
   2147483647
   $ hg debugrevspec 'wdir()~3'
   5
+  $ hg debugrevspec 'ancestors(wdir())'
+  0
+  1
+  2
+  3
+  4
+  5
+  6
+  7
+  2147483647
   $ hg debugrevspec 'wdir()~0'
   2147483647
   $ hg debugrevspec 'p1(wdir())'