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.

mercurial/subrepo.py

@@ -43,11 +43,16 def state(ctx, ui):
     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
+                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:

tests/test-subrepo-missing.t

@@ -19,6 +19,15 ignore blanklines in .hgsubstate
   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