[PATCH stable] templater: handle a missing value correctly

[Ross Lagerwall]

# HG changeset patch
# User Ross Lagerwall <rosslagerwall at gmail.com>
# Date 1344083837 -7200
# Branch stable
# Node ID ed99b19d78bd5ba28f072e5f217b4da7be209798
# Parent  e15765c18ebc18448addb955d2b698c75fc8b380
templater: handle a missing value correctly

Before, using a broken style such as:
changeset =
would result in a traceback.

This fixes a regression introduced in 63c47e4ac617.

diff --git a/mercurial/templater.py b/mercurial/templater.py
--- a/mercurial/templater.py
+++ b/mercurial/templater.py
@@ -295,6 +295,8 @@
         conf.read(mapfile)
 
         for key, val in conf[''].items():
+            if not val:
+                raise SyntaxError(_('%s: missing value') % conf.source('', key))
             if val[0] in "'\"":
                 try:
                     self.cache[key] = parsestring(val)
diff --git a/tests/test-command-template.t b/tests/test-command-template.t
--- a/tests/test-command-template.t
+++ b/tests/test-command-template.t
@@ -463,6 +463,13 @@
   abort: "changeset" not in template map
   [255]
 
+Error if style missing value:
+
+  $ echo 'changeset =' > t
+  $ hg log --style t
+  abort: t:1: missing value
+  [255]
+
 Error if include fails:
 
   $ echo 'changeset = q' >> t