Make the relation between msgid and symbol 1:1instead of 1:N

ChangeLog

@@ -233,6 +233,12 @@ Release date: TBA
 
 * Allow a `.` as a prefix for Sphinx name resolution.
 
+* Checkers must now keep a 1 to 1 relationship between "msgid" (ie: C1234) and "symbol" (ie : human-readable-symbol)
+* In checkers, an old_names can now be used for multiple new messages
+
+Caused by #1164. It means if you do a partial old_names for a message definition an exception will tell you that you
+must rename the associated identification.
+
 
 What's New in Pylint 2.3.0?
 ===========================

pylint/checkers/base.py

@@ -2131,7 +2131,7 @@ class ComparisonChecker(_BasicChecker):
             "Python is to use isinstance(x, Y) rather than "
             "type(x) == Y, type(x) is Y. Though there are unusual "
             "situations where these give different results.",
-            {"old_names": [("W0154", "unidiomatic-typecheck")]},
+            {"old_names": [("W0154", "old-unidiomatic-typecheck")]},
         ),
         "R0123": (
             "Comparison to literal",

pylint/checkers/base_checker.py

@@ -54,8 +54,8 @@ def __gt__(self, other):
 
     def __repr__(self):
         status = "Checker" if self.enabled else "Disabled checker"
-        return "{} '{}' responsible for {}".format(
-            status, self.name, ", ".join(self.msgs.keys())
+        return "{} '{}' (responsible for '{}')".format(
+            status, self.name, "', '".join(self.msgs.keys())
         )
 
     def __str__(self):

pylint/checkers/classes.py

@@ -1680,8 +1680,8 @@ class SpecialMethodsChecker(BaseChecker):
             "iterable (i.e. has no `%s` method)" % NEXT_METHOD,
             {
                 "old_names": [
-                    ("W0234", "non-iterator-returned"),
-                    ("E0234", "non-iterator-returned"),
+                    ("W0234", "old-non-iterator-returned-1"),
+                    ("E0234", "old-non-iterator-returned-2"),
                 ]
             },
         ),

pylint/checkers/imports.py

@@ -201,7 +201,7 @@ def _make_graph(filename, dep_info, sect, gtype):
         "Unable to import %s",
         "import-error",
         "Used when pylint has been unable to import a module.",
-        {"old_names": [("F0401", "import-error")]},
+        {"old_names": [("F0401", "old-import-error")]},
     ),
     "E0402": (
         "Attempted relative import beyond top-level package",

pylint/checkers/python3.py

@@ -189,22 +189,22 @@ class Python3Checker(checkers.BaseChecker):
             "Python3 will not allow implicit unpacking of "
             "exceptions in except clauses. "
             "See http://www.python.org/dev/peps/pep-3110/",
-            {"old_names": [("W0712", "unpacking-in-except")]},
+            {"old_names": [("W0712", "old-unpacking-in-except")]},
         ),
         "E1604": (
             "Use raise ErrorClass(args) instead of raise ErrorClass, args.",
             "old-raise-syntax",
             "Used when the alternate raise syntax "
             "'raise foo, bar' is used "
             "instead of 'raise foo(bar)'.",
-            {"old_names": [("W0121", "old-raise-syntax")]},
+            {"old_names": [("W0121", "old-old-raise-syntax")]},
         ),
         "E1605": (
             "Use of the `` operator",
             "backtick",
             'Used when the deprecated "``" (backtick) operator is used '
             "instead  of the str() function.",
-            {"scope": WarningScope.NODE, "old_names": [("W0333", "backtick")]},
+            {"scope": WarningScope.NODE, "old_names": [("W0333", "old-backtick")]},
         ),
         "E1609": (
             "Import * only allowed at module level",
@@ -358,14 +358,14 @@ class Python3Checker(checkers.BaseChecker):
             "indexing-exception",
             "Indexing exceptions will not work on Python 3. Use "
             "`exception.args[index]` instead.",
-            {"old_names": [("W0713", "indexing-exception")]},
+            {"old_names": [("W0713", "old-indexing-exception")]},
         ),
         "W1625": (
             "Raising a string exception",
             "raising-string",
             "Used when a string exception is raised. This will not "
             "work on Python 3.",
-            {"old_names": [("W0701", "raising-string")]},
+            {"old_names": [("W0701", "old-raising-string")]},
         ),
         "W1626": (
             "reload built-in referenced",
@@ -1369,7 +1369,7 @@ class Python3TokenChecker(checkers.BaseTokenChecker):
             "old-ne-operator",
             'Used when the deprecated "<>" operator is used instead '
             'of "!=". This is removed in Python 3.',
-            {"maxversion": (3, 0), "old_names": [("W0331", "old-ne-operator")]},
+            {"maxversion": (3, 0), "old_names": [("W0331", "old-old-ne-operator")]},
         ),
         "E1608": (
             "Use of old octal literal",

pylint/checkers/refactoring.py

@@ -141,13 +141,13 @@ class RefactoringChecker(checkers.BaseTokenChecker):
             "Used when a function or a method has too many nested "
             "blocks. This makes the code less understandable and "
             "maintainable.",
-            {"old_names": [("R0101", "too-many-nested-blocks")]},
+            {"old_names": [("R0101", "old-too-many-nested-blocks")]},
         ),
         "R1703": (
             "The if statement can be replaced with %s",
             "simplifiable-if-statement",
             "Used when an if statement can be replaced with 'bool(test)'. ",
-            {"old_names": [("R0102", "simplifiable-if-statement")]},
+            {"old_names": [("R0102", "old-simplifiable-if-statement")]},
         ),
         "R1704": (
             "Redefining argument with the local name %r",

pylint/checkers/typecheck.py

@@ -289,7 +289,7 @@ def _missing_member_hint(owner, attrname, distance_threshold, max_choices):
         "assignment-from-none",
         "Used when an assignment is done on a function call but the "
         "inferred function returns nothing but None.",
-        {"old_names": [("W1111", "assignment-from-none")]},
+        {"old_names": [("W1111", "old-assignment-from-none")]},
     ),
     "E1129": (
         "Context manager '%s' doesn't implement __enter__ and __exit__.",

pylint/checkers/variables.py

@@ -450,14 +450,14 @@ def _has_locals_call_after_node(stmt, scope):
         "left side has %d label(s), right side has %d value(s)",
         "unbalanced-tuple-unpacking",
         "Used when there is an unbalanced tuple unpacking in assignment",
-        {"old_names": [("E0632", "unbalanced-tuple-unpacking")]},
+        {"old_names": [("E0632", "old-unbalanced-tuple-unpacking")]},
     ),
     "E0633": (
         "Attempting to unpack a non-sequence%s",
         "unpacking-non-sequence",
         "Used when something which is not "
         "a sequence is used in an unpack assignment",
-        {"old_names": [("W0633", "unpacking-non-sequence")]},
+        {"old_names": [("W0633", "old-unpacking-non-sequence")]},
     ),
     "W0640": (
         "Cell variable %s defined in loop",

pylint/extensions/docparams.py

@@ -78,7 +78,7 @@ class DocstringParameterChecker(BaseChecker):
             "Missing return documentation",
             "missing-return-doc",
             "Please add documentation about what this method returns.",
-            {"old_names": [("W9007", "missing-returns-doc")]},
+            {"old_names": [("W9007", "old-missing-returns-doc")]},
         ),
         "W9012": (
             "Missing return type documentation",
@@ -91,7 +91,7 @@ class DocstringParameterChecker(BaseChecker):
             "Missing yield documentation",
             "missing-yield-doc",
             "Please add documentation about what this generator yields.",
-            {"old_names": [("W9009", "missing-yields-doc")]},
+            {"old_names": [("W9009", "old-missing-yields-doc")]},
         ),
         "W9014": (
             "Missing yield type documentation",
@@ -104,13 +104,13 @@ class DocstringParameterChecker(BaseChecker):
             '"%s" missing in parameter documentation',
             "missing-param-doc",
             "Please add parameter declarations for all parameters.",
-            {"old_names": [("W9003", "missing-param-doc")]},
+            {"old_names": [("W9003", "old-missing-param-doc")]},
         ),
         "W9016": (
             '"%s" missing in parameter type documentation',
             "missing-type-doc",
             "Please add parameter type declarations for all parameters.",
-            {"old_names": [("W9004", "missing-type-doc")]},
+            {"old_names": [("W9004", "old-missing-type-doc")]},
         ),
         "W9017": (
             '"%s" differing in parameter documentation',

pylint/message/__init__.py

@@ -43,10 +43,12 @@
 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_id_store import MessageIdStore
 
 __all__ = [
     "Message",
     "MessageDefinition",
     "MessageDefinitionStore",
     "MessagesHandlerMixIn",
+    "MessageIdStore",
 ]

pylint/message/message_definition.py

@@ -24,18 +24,26 @@ 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.check_msgid(msgid)
         self.msgid = msgid
         self.symbol = symbol
         self.msg = msg
         self.description = description
         self.scope = scope
         self.minversion = minversion
         self.maxversion = maxversion
-        self.old_names = old_names or []
+        self.old_names = []
+        if old_names:
+            for old_msgid, old_symbol in old_names:
+                self.check_msgid(old_msgid)
+                self.old_names.append([old_msgid, old_symbol])
+
+    @staticmethod
+    def check_msgid(msgid: str) -> None:
+        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))
 
     def __repr__(self):
         return "MessageDefinition:%s (%s)" % (self.symbol, self.msgid)