revset: add support for using ~ operator on wdir() predicate

We catch the WdirUnsupported exception and handles the wdir() case here.

mercurial/revset.py

@@ -383,7 +383,10 b' def ancestorspec(repo, subset, x, n, ord'
     cl = repo.changelog
     for r in getset(repo, fullreposet(repo), x):
         for i in range(n):
-            r = cl.parentrevs(r)[0]
+            try:
+                r = cl.parentrevs(r)[0]
+            except error.WdirUnsupported:
+                r = repo[r].parents()[0].rev()
         ps.add(r)
     return subset & ps
 

tests/test-revset.t

@@ -1229,6 +1229,8 b' Test working-directory revision'
   7
   $ hg debugrevspec 'wdir()^0'
   2147483647
+  $ hg debugrevspec 'wdir()~3'
+  5
   $ hg debugrevspec 'wdir()~0'
   2147483647
   $ hg debugrevspec 'p1(wdir())'