[pylint.message] Create a MessageDefinition.check_msgid function

3 files changed, 32 insertions, 18 deletions

diff --git a/pylint/message/message_definition.py b/pylint/message/message_definition.py
index cd33cd575..e54c15aae 100644
--- a/pylint/message/message_definition.py
+++ b/pylint/message/message_definition.py
@@ -24,10 +24,7 @@ class MessageDefinition:
         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
@@ -35,7 +32,18 @@ class MessageDefinition:
         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)
diff --git a/tests/message/unittest_message.py b/tests/message/unittest_message.py
index 3bc1578b5..d11eb3681 100644
--- a/tests/message/unittest_message.py
+++ b/tests/message/unittest_message.py
@@ -141,16 +141,3 @@ def test_register_error_new_id_duplicate_of_new(store):
         {"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
diff --git a/tests/message/unittest_message_definition.py b/tests/message/unittest_message_definition.py
index 0b9b05907..13ec7adae 100644
--- a/tests/message/unittest_message_definition.py
+++ b/tests/message/unittest_message_definition.py
@@ -5,11 +5,30 @@
 
 import sys
 
+import pytest
+
 from pylint.checkers import BaseChecker
 from pylint.constants import WarningScope
+from pylint.exceptions import InvalidMessageError
 from pylint.message import MessageDefinition
 
 
+@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 invalid_message_error:
+        MessageDefinition.check_msgid(msgid)
+    with pytest.raises(InvalidMessageError) as other_invalid_message_error:
+        MessageDefinition("checker", msgid, "msg", "descr", "symbol", "scope")
+    assert str(invalid_message_error.value) == expected
+    assert str(other_invalid_message_error.value) == expected
+
+
 class FalseChecker(BaseChecker):
     name = "FalseChecker"
     msgs = {