diff mercurial/ui.py @ 33329:e714159860fd

configitems: add alias support in config

Aliases define optional alternatives to existing options. For example the old
option ui.user was deprecated and replaced by ui.username. With this mechanism,
it's even possible to create an alias to an option in a different section.

Add ui.user as alias to ui.username as an example of this concept.

The old alternates principle in ui.config is removed as it was used only for
this option.

--- a/mercurial/ui.py	Mon Jul 03 13:04:35 2017 +0200
+++ b/mercurial/ui.py	Fri Jul 07 08:33:10 2017 +0200
@@ -448,38 +448,39 @@
 
     def _config(self, section, name, default=_unset, untrusted=False):
         value = default
-        if isinstance(name, list):
-            alternates = name
-        else:
-            item = self._knownconfig.get(section, {}).get(name)
-            if default is _unset:
-                if item is None:
-                    value = default
-                elif callable(item.default):
+        item = self._knownconfig.get(section, {}).get(name)
+        alternates = [(section, name)]
+
+        if item is not None:
+            alternates.extend(item.alias)
+
+        if default is _unset:
+            if item is None:
+                value = default
+            elif callable(item.default):
                     value = item.default()
-                else:
-                    value = item.default
-            elif item is not None:
-                msg = ("specifying a default value for a registered "
-                       "config item: '%s.%s' '%s'")
-                msg %= (section, name, default)
-                self.develwarn(msg, 2, 'warn-config-default')
+            else:
+                value = item.default
+        elif item is not None:
+            msg = ("specifying a default value for a registered "
+                   "config item: '%s.%s' '%s'")
+            msg %= (section, name, default)
+            self.develwarn(msg, 2, 'warn-config-default')
 
-            alternates = [name]
-
-        for n in alternates:
-            candidate = self._data(untrusted).get(section, n, None)
+        for s, n in alternates:
+            candidate = self._data(untrusted).get(s, n, None)
             if candidate is not None:
                 value = candidate
+                section = s
                 name = n
                 break
 
         if self.debugflag and not untrusted and self._reportuntrusted:
-            for n in alternates:
-                uvalue = self._ucfg.get(section, n)
+            for s, n in alternates:
+                uvalue = self._ucfg.get(s, n)
                 if uvalue is not None and uvalue != value:
                     self.debug("ignoring untrusted configuration option "
-                               "%s.%s = %s\n" % (section, n, uvalue))
+                               "%s.%s = %s\n" % (s, n, uvalue))
         return value
 
     def configsuboptions(self, section, name, default=_unset, untrusted=False):
@@ -744,7 +745,7 @@
         """
         user = encoding.environ.get("HGUSER")
         if user is None:
-            user = self.config("ui", ["username", "user"])
+            user = self.config("ui", "username")
             if user is not None:
                 user = os.path.expandvars(user)
         if user is None: