Bug 1049893 - Allow mach mercurial-setup to work if no ~/.hgrc exists; r=gps

DONTBUILD (NPOTB)

--HG--
extra : rebase_source : 8788d55cd5cfa5e64627d7951209c5f2c1222f0a

tools/mercurial/hgsetup/config.py

@@ -42,11 +42,12 @@ class MercurialConfig(object):
         # Mercurial configuration files allow an %include directive to include
         # other files, this is not supported by ConfigObj, so throw a useful
         # error saying this.
-        with open(infile, 'r') as f:
-            for line in f:
-                if line.startswith('%include'):
-                    raise HgIncludeException(
-                        '%include directive is not supported by MercurialConfig')
+        if os.path.exists(infile):
+            with open(infile, 'r') as f:
+                for line in f:
+                    if line.startswith('%include'):
+                        raise HgIncludeException(
+                            '%include directive is not supported by MercurialConfig')
 
         # write_empty_values is necessary to prevent built-in extensions (which
         # have no value) from being dropped on write.