[PATCH 2 of 2] revsets: more informative syntax error message

[Ryan McElroy]

# HG changeset patch
# User Ryan McElroy <rmcelroy at fb.com>
# Date 1428983585 25200
#      Mon Apr 13 20:53:05 2015 -0700
# Node ID e2e2371e3b2e343224bf44b9571904eb8a88ee44
# Parent  e92f07c0e06691df67b06488c37b8b742b667809
revsets: more informative syntax error message

I came across a case where an internal command was using a revset that I didn't
immediately pass in and it was difficult to debug what was going wrong with the
revset. This prints out the revset and informs the user that the error is with
a rebset so it should be more obvious what and where the error is.

diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -241,7 +241,8 @@ def tokenize(program, lookup=None, symin
                 yield ('symbol', sym, s)
             pos -= 1
         else:
-            raise error.ParseError(_("syntax error"), pos)
+            raise error.ParseError(_("syntax error in revset '%s'") %
+                                   program, pos)
         pos += 1
     yield ('end', None, pos)
 
diff --git a/tests/test-revset.t b/tests/test-revset.t
--- a/tests/test-revset.t
+++ b/tests/test-revset.t
@@ -1535,7 +1535,7 @@ test in problematic encoding
 
 test error message of bad revset
   $ hg log -r 'foo\\'
-  hg: parse error at 3: syntax error
+  hg: parse error at 3: syntax error in revset 'foo\\'
   [255]
 
   $ cd ..