give better error message on non-existent mapfile (issue813)

mercurial/templater.py

@@ -7,6 +7,7 b''
 
 from i18n import _
 import re, sys, os
+from mercurial import util
 
 def parsestring(s, quoted=True):
     '''parse a string using simple c-like syntax.
@@ -55,6 +56,9 b' class templater(object):'
 
         if not mapfile:
             return
+        if not os.path.exists(mapfile):
+            raise util.Abort(_('style not found: %s') % mapfile)
+
         i = 0
         for l in file(mapfile):
             l = l.strip()

tests/test-command-template.out

@@ -83,7 +83,7 b' 0:-1,-1 1e4e1b8f71e0 1970-01-12 13:4'
 # error if style not readable
 abort: Permission denied: ./q
 # error if no style
-abort: No such file or directory: notexist
+abort: style not found: notexist
 # error if style missing key
 abort: ./t: no key named 'changeset'
 # error if include fails