Take first steps to use the symbolic name internally instead of the numeric id.

This changeset changes utils.py to use the symbolic name as the primary key in _messages,
and the numeric ID as an alternative name in a new dictionary.

Also prepares the codebase for supporting renamed messages.

3 files changed, 39 insertions, 26 deletions

diff --git a/lint.py b/lint.py
index 7f736f55e..812a953b8 100644
--- a/lint.py
+++ b/lint.py
@@ -518,7 +518,7 @@ This is used by the global evaluation report (RP0004).'}),
                 if first <= lineno <= last:
                     # Set state for all lines for this block, if the
                     # warning is applied to nodes.
-                    if self._messages[msgid].scope == WarningScope.NODE:
+                    if self.check_message_id(msgid).scope == WarningScope.NODE:
                         if lineno > firstchildlineno:
                             state = True
                         first_, last_ = node.block_range(lineno)
diff --git a/test/test_func.py b/test/test_func.py
index 56bb82c7e..833d72779 100644
--- a/test/test_func.py
+++ b/test/test_func.py
@@ -54,7 +54,7 @@ class TestTests(testlib.TestCase):
     @testlib.tag('coverage')
     def test_exhaustivity(self):
         # skip fatal messages
-        todo = [msgid for msgid in linter._messages if msgid[0] != 'F']
+        todo = [msg.msgid for msg in linter.messages if msg.msgid[0] != 'F']
         for msgid in test_reporter.message_ids:
             try:
                 todo.remove(msgid)
diff --git a/utils.py b/utils.py
index 875ac10fc..c84dc87d6 100644
--- a/utils.py
+++ b/utils.py
@@ -189,10 +189,15 @@ class MessagesHandlerMixIn(object):
     """
 
     def __init__(self):
-        # dictionary of registered messages
+        # Primary registry for all active messages (i.e. all messages
+        # that can be emitted by pylint for the underlying Python
+        # version). It contains the 1:1 mapping from symbolic names
+        # to message definition objects.
         self._messages = {}
-        # dictionary from string symbolic id to Message object.
-        self._messages_by_symbol = {}
+        # Maps alternative names (numeric IDs, deprecated names) to 
+        # message definitions. May contain several names for each definition
+        # object.
+        self._alternative_names = {}
         self._msgs_state = {}
         self._module_msgs_state = {} # None
         self._raw_module_msgs_state = {}
@@ -213,10 +218,10 @@ class MessagesHandlerMixIn(object):
         chkid = None
         for msgid, msg_tuple in checker.msgs.iteritems():
             msg = build_message_def(checker, msgid, msg_tuple)
-            assert msg.symbol not in self._messages_by_symbol, \
+            assert msg.symbol not in self._messages, \
                     'Message symbol %r is already defined' % msg.symbol
             # avoid duplicate / malformed ids
-            assert msg.msgid not in self._messages, \
+            assert msg.msgid not in self._alternative_names, \
                    'Message id %r is already defined' % msgid
             assert chkid is None or chkid == msg.msgid[1:3], \
                    'Inconsistent checker part in message id %r' % msgid
@@ -224,8 +229,8 @@ class MessagesHandlerMixIn(object):
             if not msg.may_be_emitted():
                 self._msgs_state[msg.msgid] = False
                 continue
-            self._messages[msg.msgid] = msg
-            self._messages_by_symbol[msg.symbol] = msg
+            self._messages[msg.symbol] = msg
+            self._alternative_names[msg.msgid] = msg
             self._msgs_by_category.setdefault(msg.msgid[0], []).append(msg.msgid)
 
     def disable(self, msgid, scope='package', line=None):
@@ -246,7 +251,7 @@ class MessagesHandlerMixIn(object):
         if msgid.lower() in self._checkers:
             for checker in self._checkers[msgid.lower()]:
                 for _msgid in checker.msgs:
-                    if _msgid in self._messages:
+                    if _msgid in self._alternative_names:
                         self.disable(_msgid, scope, line)
             return
         # msgid is report id?
@@ -312,13 +317,14 @@ class MessagesHandlerMixIn(object):
 
         Raises UnknownMessage if the message id is not defined.
         """
-        if msgid in self._messages_by_symbol:
-            return self._messages_by_symbol[msgid]
-        msgid = msgid.upper()
-        try:
-            return self._messages[msgid]
-        except KeyError:
-            raise UnknownMessage('No such message id %s' % msgid)
+        if msgid[1:].isdigit():
+            msgid = msgid.upper()
+        for source in (self._alternative_names, self._messages):
+            try:
+                return source[msgid]
+            except KeyError:
+                pass
+        raise UnknownMessage('No such message id %s' % msgid)
 
     def get_msg_display_string(self, msgid):
         """Generates a user-consumable representation of a message.
@@ -335,14 +341,19 @@ class MessagesHandlerMixIn(object):
         except (KeyError, TypeError):
             return MSG_STATE_SCOPE_CONFIG
 
-    def is_message_enabled(self, msgid, line=None):
+    def is_message_enabled(self, msg_descr, line=None):
         """return true if the message associated to the given message id is
         enabled
 
         msgid may be either a numeric or symbolic message id.
         """
-        if msgid in self._messages_by_symbol:
-            msgid = self._messages_by_symbol[msgid].msgid
+        try:
+            msgid = self.check_message_id(msg_descr).msgid
+        except UnknownMessage:
+            # The linter checks for messages that are not registered
+            # due to version mismatch, just treat them as message IDs
+            # for now.
+            msgid = msg_descr
         if line is None:
             return self._msgs_state.get(msgid, True)
         try:
@@ -487,14 +498,16 @@ class MessagesHandlerMixIn(object):
                 print
             print
 
+    @property
+    def messages(self):
+        """The list of all active messages."""
+        return self._messages.itervalues()
+
     def list_messages(self):
         """output full messages list documentation in ReST format"""
-        msgids = []
-        for msgid in self._messages:
-            msgids.append(msgid)
-        msgids.sort()
-        for msgid in msgids:
-            print self.check_message_id(msgid).format_help(checkerref=False)
+        msgs = sorted(self._messages.itervalues(), key=lambda msg: msg.msgid)
+        for msg in msgs:
+            print msg.format_help(checkerref=False)
         print