subrepo: do not traceback on .hgsubstate parsing errors stable

subrepo: do not traceback on .hgsubstate parsing errors

Note that aborting in subrepo.state() prevents "repairing" commands like revert
to be issued. The user will have to edit the .hgsubstate manually (but he
probably had already otherwise this would not be failing). The same behaviour
already happens with invalid .hgsub entries.

--- a/mercurial/subrepo.py	Fri May 04 14:19:52 2012 +0200
+++ b/mercurial/subrepo.py	Fri May 04 14:19:55 2012 +0200
@@ -43,11 +43,16 @@
     rev = {}
     if '.hgsubstate' in ctx:
         try:
-            for l in ctx['.hgsubstate'].data().splitlines():
+            for i, l in enumerate(ctx['.hgsubstate'].data().splitlines()):
                 l = l.lstrip()
                 if not l:
                     continue
-                revision, path = l.split(" ", 1)
+                try:
+                    revision, path = l.split(" ", 1)
+                except ValueError:
+                    raise util.Abort(_("invalid subrepository revision "
+                                       "specifier in .hgsubstate line %d")
+                                     % (i + 1))
                 rev[path] = revision
         except IOError, err:
             if err.errno != errno.ENOENT:

--- a/tests/test-subrepo-missing.t	Fri May 04 14:19:52 2012 +0200
+++ b/tests/test-subrepo-missing.t	Fri May 04 14:19:55 2012 +0200
@@ -19,6 +19,15 @@
   M .hgsubstate
   $ hg revert -qC .hgsubstate
 
+abort more gracefully on .hgsubstate parsing error
+
+  $ cp .hgsubstate .hgsubstate.old
+  >>> file('.hgsubstate', 'wb').write('\ninvalid')
+  $ hg st --subrepos
+  abort: invalid subrepository revision specifier in .hgsubstate line 2
+  [255]
+  $ mv .hgsubstate.old .hgsubstate
+
 delete .hgsub and revert it
 
   $ rm .hgsub