Create a MessageId class

pylint/checkers/utils.py

@@ -896,7 +896,7 @@ def get_exception_handlers(
         return [
             handler for handler in context.handlers if error_of_type(handler, exception)
         ]
-    return None
+    return []
 
 
 def is_node_inside_try_except(node: astroid.Raise) -> bool:

pylint/lint.py

@@ -78,7 +78,7 @@
 from pylint import checkers, config, exceptions, interfaces, reporters
 from pylint.__pkginfo__ import version
 from pylint.constants import MAIN_CHECKER_NAME, MSG_TYPES, OPTION_RGX
-from pylint.message import Message, MessagesHandlerMixIn, MessagesStore
+from pylint.message import Message, MessageDefinitionStore, MessagesHandlerMixIn
 from pylint.reporters.ureports import nodes as report_nodes
 from pylint.utils import ASTWalker, FileState, utils
 
@@ -593,7 +593,7 @@ def __init__(self, options=(), reporter=None, option_groups=(), pylintrc=None):
         # some stuff has to be done before ancestors initialization...
         #
         # messages store / checkers / reporter / astroid manager
-        self.msgs_store = MessagesStore()
+        self.msgs_store = MessageDefinitionStore()
         self.reporter = None
         self._reporter_name = None
         self._reporters = {}

pylint/message/__init__.py

@@ -41,7 +41,14 @@
 
 from pylint.message.message import Message
 from pylint.message.message_definition import MessageDefinition
+from pylint.message.message_definition_store import MessageDefinitionStore
 from pylint.message.message_handler_mix_in import MessagesHandlerMixIn
-from pylint.message.message_store import MessagesStore
+from pylint.message.message_id import MessageId
 
-__all__ = ["Message", "MessageDefinition", "MessagesHandlerMixIn", "MessagesStore"]
+__all__ = [
+    "Message",
+    "MessageDefinition",
+    "MessageDefinitionStore",
+    "MessagesHandlerMixIn",
+    "MessageId",
+]

pylint/message/message_definition.py

@@ -5,8 +5,7 @@
 
 import sys
 
-from pylint.constants import MSG_TYPES
-from pylint.exceptions import InvalidMessageError
+from pylint.message.message_id import MessageId
 from pylint.utils import normalize_text
 
 
@@ -24,19 +23,23 @@ def __init__(
         old_names=None,
     ):
         self.checker = checker
-        if len(msgid) != 5:
-            raise InvalidMessageError("Invalid message id %r" % msgid)
-        if not msgid[0] in MSG_TYPES:
-            raise InvalidMessageError("Bad message type %s in %r" % (msgid[0], msgid))
-        self.msgid = msgid
+        MessageId.check_msgid(msgid)
+        self.message_id = MessageId(msgid, symbol)
         self.msg = msg
         self.description = description
-        self.symbol = symbol
         self.scope = scope
         self.minversion = minversion
         self.maxversion = maxversion
         self.old_names = old_names or []
 
+    @property
+    def symbol(self):
+        return self.message_id.symbol
+
+    @property
+    def msgid(self):
+        return self.message_id.msgid
+
     def __repr__(self):
         return "MessageDefinition:%s (%s)" % (self.symbol, self.msgid)
 
@@ -57,10 +60,6 @@ def format_help(self, checkerref=False):
         if checkerref:
             desc += " This message belongs to the %s checker." % self.checker.name
         title = self.msg
-        if self.symbol:
-            msgid = "%s (%s)" % (self.symbol, self.msgid)
-        else:
-            msgid = self.msgid
         if self.minversion or self.maxversion:
             restr = []
             if self.minversion:
@@ -75,6 +74,5 @@ def format_help(self, checkerref=False):
         desc = normalize_text(" ".join(desc.split()), indent="  ")
         if title != "%s":
             title = title.splitlines()[0]
-
-            return ":%s: *%s*\n%s" % (msgid, title.rstrip(" "), desc)
-        return ":%s:\n%s" % (msgid, desc)
+            return ":%s: *%s*\n%s" % (self.message_id, title.rstrip(" "), desc)
+        return ":%s:\n%s" % (self.message_id, desc)

pylint/message/message_store.py → pylint/message/message_definition_store.py

@@ -10,7 +10,7 @@
 from pylint.exceptions import InvalidMessageError, UnknownMessageError
 
 
-class MessagesStore:
+class MessageDefinitionStore:
 
     """The messages store knows information about every possible message but has
     no particular state during analysis.

pylint/message/message_handler_mix_in.py

@@ -244,14 +244,11 @@ def add_message(
                 message_definition, line, node, args, confidence, col_offset
             )
 
-    def add_one_message(
-        self, message_definition, line, node, args, confidence, col_offset
-    ):
-        # backward compatibility, message may not have a symbol
-        symbol = message_definition.symbol or message_definition.msgid
-        # Fatal messages and reports are special, the node/scope distinction
-        # does not apply to them.
+    @staticmethod
+    def check_message_definition(message_definition, line, node):
         if message_definition.msgid[0] not in _SCOPE_EXEMPT:
+            # Fatal messages and reports are special, the node/scope distinction
+            # does not apply to them.
             if message_definition.scope == WarningScope.LINE:
                 if line is None:
                     raise InvalidMessageError(
@@ -271,6 +268,12 @@ def add_one_message(
                         % message_definition.msgid
                     )
 
+    def add_one_message(
+        self, message_definition, line, node, args, confidence, col_offset
+    ):
+        # backward compatibility, message may not have a symbol
+        symbol = message_definition.symbol or message_definition.msgid
+        self.check_message_definition(message_definition, line, node)
         if line is None and node is not None:
             line = node.fromlineno
         if col_offset is None and hasattr(node, "col_offset"):

pylint/message/message_id.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+from pylint.constants import MSG_TYPES
+from pylint.exceptions import InvalidMessageError
+
+
+class MessageId:
+    def __init__(self, msgid, symbol):
+        self.msgid = msgid
+        self.symbol = symbol
+
+    def __str__(self):
+        return "%s (%s)" % (self.symbol, self.msgid)
+
+    def __hash__(self):
+        return "{}-{}".format(self.msgid, self.symbol).__hash__()
+
+    def __eq__(self, other):
+        return self.msgid == other.msgid and self.symbol == other.symbol
+
+    @staticmethod
+    def check_msgid(msgid: str) -> None:
+        """This is a static method used in MessageDefinition and not the
+        MessageId constructor for performance reasons."""
+        if len(msgid) != 5:
+            raise InvalidMessageError("Invalid message id %r" % msgid)
+        if msgid[0] not in MSG_TYPES:
+            raise InvalidMessageError("Bad message type %s in %r" % (msgid[0], msgid))

tests/message/unittest_message.py

@@ -7,12 +7,12 @@
 
 from pylint.checkers import BaseChecker
 from pylint.exceptions import InvalidMessageError
-from pylint.message import MessageDefinition, MessagesStore
+from pylint.message import MessageDefinition, MessageDefinitionStore
 
 
 @pytest.fixture
 def store():
-    return MessagesStore()
+    return MessageDefinitionStore()
 
 
 @pytest.mark.parametrize(
@@ -141,16 +141,3 @@ class CheckerTwo(BaseChecker):
         {"W1234": ("message two", "msg-symbol-two", "another msg description.")},
         "Message id 'W1234' cannot have both 'msg-symbol-one' and 'msg-symbol-two' as symbolic name.",
     )
-
-
-@pytest.mark.parametrize(
-    "msgid,expected",
-    [
-        ("Q1234", "Bad message type Q in 'Q1234'"),
-        ("W12345", "Invalid message id 'W12345'"),
-    ],
-)
-def test_create_invalid_message_type(msgid, expected):
-    with pytest.raises(InvalidMessageError) as cm:
-        MessageDefinition("checker", msgid, "msg", "descr", "symbol", "scope")
-    assert str(cm.value) == expected

tests/message/unittest_message_store.py → tests/message/unittest_message_definition_store.py

@@ -10,12 +10,12 @@
 
 from pylint.checkers import BaseChecker
 from pylint.exceptions import InvalidMessageError, UnknownMessageError
-from pylint.message import MessageDefinition, MessagesStore
+from pylint.message import MessageDefinition, MessageDefinitionStore
 
 
 @pytest.fixture
 def store():
-    store = MessagesStore()
+    store = MessageDefinitionStore()
 
     class Checker(BaseChecker):
         name = "achecker"

tests/message/unittest_message_id.py

@@ -0,0 +1,53 @@
+# -*- coding: utf-8 -*-
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+import pytest
+
+from pylint.exceptions import InvalidMessageError
+from pylint.message import MessageId
+
+
+@pytest.fixture
+def msgid():
+    return "W1234"
+
+
+@pytest.fixture
+def symbol():
+    return "msg-symbol"
+
+
+@pytest.fixture
+def message_id(msgid, symbol):
+    return MessageId(msgid, symbol)
+
+
+@pytest.mark.parametrize(
+    "msgid,expected",
+    [
+        ("Q1234", "Bad message type Q in 'Q1234'"),
+        ("W12345", "Invalid message id 'W12345'"),
+    ],
+)
+def test_create_invalid_message_type(msgid, expected):
+    with pytest.raises(InvalidMessageError) as cm:
+        MessageId.check_msgid(msgid)
+    assert str(cm.value) == expected
+
+
+def test_hash_and_eq(message_id):
+    """MessageId should be hashable"""
+    dict_ = {}
+    message_id_2 = MessageId("W1235", "msg-symbol-2")
+    dict_[message_id] = 1
+    dict_[message_id_2] = 2
+    assert dict_[message_id] != dict_[message_id_2]
+    assert message_id != message_id_2
+
+
+def test_str(message_id, msgid, symbol):
+    result = str(message_id)
+    assert msgid in result
+    assert symbol in result