[trailing-comma-tuple] Properly emit when disabled globally and enabled locally

Author: Pierre-Sassoulas

.pyenchant_pylint_custom_dict.txt

@@ -336,6 +336,7 @@ testoptions
 tmp
 tokencheckers
 tokeninfo
+tokenization
 tokenize
 tokenizer
 toml

doc/data/messages/t/trailing-comma-tuple/details.rst

@@ -0,0 +1,4 @@
+``trailing-comma-tuple`` should now be correctly emitted when it was disabled globally
+but enabled via local message control, after removal of an over-optimisation.
+
+Refs #9608.

doc/whatsnew/fragments/9608.bugfix

@@ -652,9 +652,26 @@ def process_tokens(self, tokens: list[tokenize.TokenInfo]) -> None:
         trailing_comma_tuple_enabled_for_file = self.linter.is_message_enabled(
             "trailing-comma-tuple"
         )
+        trailing_comma_tuple_enabled_once: bool = trailing_comma_tuple_enabled_for_file
         # Process tokens and look for 'if' or 'elif'
         for index, token in enumerate(tokens):
             token_string = token[1]
+            if (
+                not trailing_comma_tuple_enabled_once
+                and token_string.startswith("#")
+                # We have at least 1 '#' (one char) at the start of the token
+                and all(c in token_string[1:] for c in ("pylint:", "enable="))
+                # We have at least '#' 'pylint'  / 'enable' (15 char) at the
+                and any(  # start of the token
+                    c in token_string[15:] for c in ("trailing-comma-tuple", "R1707")
+                )
+            ):
+                # Way to not have to check if "trailing-comma-tuple" is enabled or
+                # disabled on each line: Any enable for it during tokenization and
+                # we'll start using the costly '_is_trailing_comma' to check if we
+                # need to raise the message. We still won't raise if it's disabled
+                # again due to the usual generic message control handling later.
+                trailing_comma_tuple_enabled_once = True
             if token_string == "elif":
                 # AST exists by the time process_tokens is called, so
                 # it's safe to assume tokens[index+1] exists.
@@ -663,9 +680,14 @@ def process_tokens(self, tokens: list[tokenize.TokenInfo]) -> None:
                 # token[2] is the actual position and also is
                 # reported by IronPython.
                 self._elifs.extend([token[2], tokens[index + 1][2]])
-            elif trailing_comma_tuple_enabled_for_file and _is_trailing_comma(
-                tokens, index
-            ):
+            elif (
+                trailing_comma_tuple_enabled_for_file
+                or trailing_comma_tuple_enabled_once
+            ) and _is_trailing_comma(tokens, index):
+                # If "trailing-comma-tuple" is enabled globally we always check _is_trailing_comma
+                # it might be for nothing if there's a local disable, or if the message control is
+                # not enabling 'trailing-comma-tuple', but the alternative is having to check if
+                # it's enabled for a line each line (just to avoid calling '_is_trailing_comma').
                 self.add_message(
                     "trailing-comma-tuple", line=token.start[0], confidence=HIGH
                 )

pylint/checkers/refactoring/refactoring_checker.py

@@ -305,12 +305,14 @@ def is_message_enabled(
         line: int | None = None,
         confidence: interfaces.Confidence | None = None,
     ) -> bool:
-        """Return whether this message is enabled for the current file, line and
-        confidence level.
+        """Is this message enabled for the current file ?
 
-        This function can't be cached right now as the line is the line of
-        the currently analysed file (self.file_state), if it changes, then the
-        result for the same msg_descr/line might need to change.
+        Optionally, is it enabled for this line and confidence level ?
+
+        The current file is implicit and mandatory. As a result this function
+        can't be cached right now as the line is the line of the currently
+        analysed file (self.file_state), if it changes, then the result for
+        the same msg_descr/line might need to change.
 
         :param msg_descr: Either the msgid or the symbol for a MessageDefinition
         :param line: The line of the currently analysed file

pylint/lint/message_state_handler.py

@@ -48,3 +48,13 @@ def some_other_func():
 
 JJJ = some_func(0,
     0)
+
+# pylint: disable-next=trailing-comma-tuple
+AAA = 1,
+BBB = "aaaa", # [trailing-comma-tuple]
+# pylint: disable=trailing-comma-tuple
+CCC="aaa",
+III = some_func(0,
+    0),
+# pylint: enable=trailing-comma-tuple
+FFF=['f'], # [trailing-comma-tuple]

tests/functional/t/trailing_comma_tuple.py

@@ -7,3 +7,5 @@ trailing-comma-tuple:34:0:None:None::Disallow trailing comma tuple:HIGH
 trailing-comma-tuple:38:0:None:None::Disallow trailing comma tuple:HIGH
 trailing-comma-tuple:41:0:None:None::Disallow trailing comma tuple:HIGH
 trailing-comma-tuple:47:0:None:None::Disallow trailing comma tuple:HIGH
+trailing-comma-tuple:54:0:None:None::Disallow trailing comma tuple:HIGH
+trailing-comma-tuple:60:0:None:None::Disallow trailing comma tuple:HIGH

tests/functional/t/trailing_comma_tuple.txt

@@ -0,0 +1,24 @@
+"""Check trailing comma tuple optimization."""
+# pylint: disable=missing-docstring
+
+AAA = 1,
+BBB = "aaaa",
+CCC="aaa",
+FFF=['f'],
+
+def some_func(first, second):
+    if first:
+        return first,
+    if second:
+        return (first, second,)
+    return first, second,
+
+# pylint: enable=trailing-comma-tuple
+AAA = 1,  # [trailing-comma-tuple]
+BBB = "aaaa", # [trailing-comma-tuple]
+# pylint: disable=trailing-comma-tuple
+CCC="aaa",
+III = some_func(0,
+    0),
+# pylint: enable=trailing-comma-tuple
+FFF=['f'], # [trailing-comma-tuple]

tests/functional/t/trailing_comma_tuple_9608.py

@@ -0,0 +1,5 @@
+[MAIN]
+disable=trailing-comma-tuple
+
+[testoptions]
+exclude_from_minimal_messages_config=True

tests/functional/t/trailing_comma_tuple_9608.rc

@@ -0,0 +1,3 @@
+trailing-comma-tuple:17:0:None:None::Disallow trailing comma tuple:HIGH
+trailing-comma-tuple:18:0:None:None::Disallow trailing comma tuple:HIGH
+trailing-comma-tuple:24:0:None:None::Disallow trailing comma tuple:HIGH