[PATCH V2] identify: avoid a crash when given '-r wdir()'

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1435531198 14400
#      Sun Jun 28 18:39:58 2015 -0400
# Node ID 46033c2b55b71c40b32315f16f5524b0295e64dc
# Parent  6fb8a76fa2afa847734c15ef7b2e22a94505c591
identify: avoid a crash when given '-r wdir()'

The crash was 'NoneType is not subscriptable' in hexfunc(ctx.node()), because
the node for wdir() is None.  This can be avoided simply by detecting 'wdir()'
and taking the existing path for no given revision.

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4064,7 +4064,9 @@ def identify(ui, repo, source=None, rev=
             if bm:
                 output.append(bm)
     else:
-        if not rev:
+        ctx = scmutil.revsingle(repo, rev, None)
+
+        if ctx.rev() is None:
             ctx = repo[None]
             parents = ctx.parents()
             changed = ""
@@ -4079,7 +4081,6 @@ def identify(ui, repo, source=None, rev=
                 output.append("%s%s" %
                   ('+'.join([str(p.rev()) for p in parents]), changed))
         else:
-            ctx = scmutil.revsingle(repo, rev)
             if default or id:
                 output = [hexfunc(ctx.node())]
             if num:
diff --git a/tests/test-tags.t b/tests/test-tags.t
--- a/tests/test-tags.t
+++ b/tests/test-tags.t
@@ -47,6 +47,8 @@ Setup:
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg identify
   acb14030fe0a tip
+  $ hg identify -r 'wdir()'
+  acb14030fe0a tip
   $ cacheexists
   tag cache exists
 No fnodes cache because .hgtags file doesn't exist
@@ -174,6 +176,8 @@ Create a branch:
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg id
   acb14030fe0a+ first
+  $ hg id -r 'wdir()'
+  acb14030fe0a+ first
   $ hg -v id
   acb14030fe0a+ first
   $ hg status