Refactor MessageId Store with a better error message

3 files changed, 18 insertions, 11 deletions

diff --git a/pylint/message/message_handler_mix_in.py b/pylint/message/message_handler_mix_in.py
index 46a29116c..94d36c6a9 100644
--- a/pylint/message/message_handler_mix_in.py
+++ b/pylint/message/message_handler_mix_in.py
@@ -45,14 +45,13 @@ class MessagesHandlerMixIn:
     def _register_by_id_managed_msg(self, msgid_or_symbol: str, line, is_disabled=True):
         """If the msgid is a numeric one, then register it to inform the user
         it could furnish instead a symbolic msgid."""
-        try:
-            if msgid_or_symbol[1:].isdigit():
+        if msgid_or_symbol[1:].isdigit():
+            try:
                 symbol = self.msgs_store.message_id_store.get_symbol(msgid=msgid_or_symbol)  # type: ignore
-                msgid = msgid_or_symbol
-                managed = (self.current_name, msgid, symbol, line, is_disabled)  # type: ignore
-                MessagesHandlerMixIn.__by_id_managed_msgs.append(managed)
-        except KeyError:
-            pass
+            except UnknownMessageError:
+                return
+            managed = (self.current_name, msgid_or_symbol, symbol, line, is_disabled)  # type: ignore
+            MessagesHandlerMixIn.__by_id_managed_msgs.append(managed)
 
     def disable(self, msgid, scope="package", line=None, ignore_unknown=False):
         self._set_msg_status(
diff --git a/pylint/message/message_id_store.py b/pylint/message/message_id_store.py
index 438136cb5..3f156fcb8 100644
--- a/pylint/message/message_id_store.py
+++ b/pylint/message/message_id_store.py
@@ -26,10 +26,18 @@ class MessageIdStore:
         return result
 
     def get_symbol(self, msgid: str) -> str:
-        return self.__msgid_to_symbol[msgid]
+        try:
+            return self.__msgid_to_symbol[msgid]
+        except KeyError as e:
+            msg = f"'{msgid}' is not stored in the message store."
+            raise UnknownMessageError(msg) from e
 
     def get_msgid(self, symbol: str) -> str:
-        return self.__symbol_to_msgid[symbol]
+        try:
+            return self.__symbol_to_msgid[symbol]
+        except KeyError as e:
+            msg = f"'{symbol}' is not stored in the message store."
+            raise UnknownMessageError(msg) from e
 
     def register_message_definition(self, message_definition):
         self.check_msgid_and_symbol(message_definition.msgid, message_definition.symbol)
diff --git a/tests/message/unittest_message_id_store.py b/tests/message/unittest_message_id_store.py
index ba89a4610..ad4ca3d9f 100644
--- a/tests/message/unittest_message_id_store.py
+++ b/tests/message/unittest_message_id_store.py
@@ -55,9 +55,9 @@ def test_add_msgid_and_symbol(empty_msgid_store):
     assert empty_msgid_store.get_symbol("E1235") == "new-sckiil"
     assert empty_msgid_store.get_msgid("old-sckiil") == "C1235"
     assert empty_msgid_store.get_msgid("new-sckiil") == "E1235"
-    with pytest.raises(KeyError):
+    with pytest.raises(UnknownMessageError):
         empty_msgid_store.get_symbol("C1234")
-    with pytest.raises(KeyError):
+    with pytest.raises(UnknownMessageError):
         empty_msgid_store.get_msgid("not-exist")