templater: simplify merge of __base__ dicts by reading it first

mercurial/templater.py

@@ -1344,15 +1344,9 b' def _readmapfile(mapfile):'
 
     cache = {}
     tmap = {}
-    for key, val in conf[''].items():
-        if not val:
-            raise error.ParseError(_('missing value'), conf.source('', key))
-        if val[0] in "'\"":
-            if val[0] != val[-1]:
-                raise error.ParseError(_('unmatched quotes'),
-                                       conf.source('', key))
-            cache[key] = unquotestring(val)
-        elif key == "__base__":
+
+    val = conf.get('', '__base__')
+    if val and val[0] not in "'\"":
             # treat as a pointer to a base class for this style
             path = util.normpath(os.path.join(base, val))
 
@@ -1368,14 +1362,17 b' def _readmapfile(mapfile):'
                         path = p3
                         break
 
-            bcache, btmap = _readmapfile(path)
-            for k in bcache:
-                if k not in cache:
-                    cache[k] = bcache[k]
-            for k in btmap:
-                if k not in tmap:
-                    tmap[k] = btmap[k]
-        else:
+        cache, tmap = _readmapfile(path)
+
+    for key, val in conf[''].items():
+        if not val:
+            raise error.ParseError(_('missing value'), conf.source('', key))
+        if val[0] in "'\"":
+            if val[0] != val[-1]:
+                raise error.ParseError(_('unmatched quotes'),
+                                       conf.source('', key))
+            cache[key] = unquotestring(val)
+        elif key != '__base__':
             val = 'default', val
             if ':' in val[1]:
                 val = val[1].split(':', 1)