Make ``Message`` a ``dataclass`` (#6381)

4 files changed, 68 insertions, 88 deletions

diff --git a/pylint/lint/parallel.py b/pylint/lint/parallel.py
index 7f160e328..98a2af5be 100644
--- a/pylint/lint/parallel.py
+++ b/pylint/lint/parallel.py
@@ -16,7 +16,7 @@ import dill
 from pylint import reporters
 from pylint.lint.utils import _patch_sys_path
 from pylint.message import Message
-from pylint.typing import FileItem, MessageLocationTuple
+from pylint.typing import FileItem
 from pylint.utils import LinterStats, merge_stats
 
 try:
@@ -32,18 +32,6 @@ if TYPE_CHECKING:
 _worker_linter = None
 
 
-def _get_new_args(message):
-    location = (
-        message.abspath,
-        message.path,
-        message.module,
-        message.obj,
-        message.line,
-        message.column,
-    )
-    return (message.msg_id, message.symbol, location, message.msg, message.confidence)
-
-
 def _worker_initialize(
     linter: bytes, arguments: None | str | Sequence[str] = None
 ) -> None:
@@ -67,7 +55,14 @@ def _worker_initialize(
 def _worker_check_single_file(
     file_item: FileItem,
 ) -> tuple[
-    int, Any, str, Any, list[tuple[Any, ...]], LinterStats, Any, defaultdict[Any, list]
+    int,
+    Any,
+    str,
+    Any,
+    list[Message],
+    LinterStats,
+    Any,
+    defaultdict[Any, list],
 ]:
     if not _worker_linter:
         raise Exception("Worker linter not yet initialised")
@@ -80,7 +75,7 @@ def _worker_check_single_file(
         except AttributeError:
             continue
         mapreduce_data[checker.name].append(data)
-    msgs = [_get_new_args(m) for m in _worker_linter.reporter.messages]
+    msgs = _worker_linter.reporter.messages
     _worker_linter.reporter.reset()
     if _worker_linter.current_name is None:
         warnings.warn(
@@ -162,9 +157,6 @@ def check_parallel(
             linter.file_state.base_name = base_name
             linter.set_current_module(module, file_path)
             for msg in messages:
-                msg = Message(
-                    msg[0], msg[1], MessageLocationTuple(*msg[2]), msg[3], msg[4]
-                )
                 linter.reporter.handle_message(msg)
             all_stats.append(stats)
             all_mapreduce_data[worker_idx].append(mapreduce_data)
diff --git a/pylint/message/message.py b/pylint/message/message.py
index 67f787572..4efa3f124 100644
--- a/pylint/message/message.py
+++ b/pylint/message/message.py
@@ -4,85 +4,71 @@
 
 from __future__ import annotations
 
-import collections
-from typing import overload
+from dataclasses import asdict, dataclass
 from warnings import warn
 
 from pylint.constants import MSG_TYPES
-from pylint.interfaces import Confidence
+from pylint.interfaces import UNDEFINED, Confidence
 from pylint.typing import MessageLocationTuple
 
-_MsgBase = collections.namedtuple(
-    "_MsgBase",
-    [
-        "msg_id",
-        "symbol",
-        "msg",
-        "C",
-        "category",
-        "confidence",
-        "abspath",
-        "path",
-        "module",
-        "obj",
-        "line",
-        "column",
-        "end_line",
-        "end_column",
-    ],
-)
 
-
-class Message(_MsgBase):
+@dataclass(unsafe_hash=True)
+class Message:  # pylint: disable=too-many-instance-attributes
     """This class represent a message to be issued by the reporters."""
 
-    @overload
-    def __new__(
-        cls,
-        msg_id: str,
-        symbol: str,
-        location: MessageLocationTuple,
-        msg: str,
-        confidence: Confidence | None,
-    ) -> Message:
-        ...
-
-    @overload
-    def __new__(
-        cls,
-        msg_id: str,
-        symbol: str,
-        location: tuple[str, str, str, str, int, int],
-        msg: str,
-        confidence: Confidence | None,
-    ) -> Message:
-        # Remove for pylint 3.0
-        ...
+    msg_id: str
+    symbol: str
+    msg: str
+    C: str
+    category: str
+    confidence: Confidence
+    abspath: str
+    path: str
+    module: str
+    obj: str
+    line: int
+    column: int
+    end_line: int | None
+    end_column: int | None
 
-    def __new__(
-        cls,
+    def __init__(
+        self,
         msg_id: str,
         symbol: str,
         location: tuple[str, str, str, str, int, int] | MessageLocationTuple,
         msg: str,
         confidence: Confidence | None,
-    ) -> Message:
+    ) -> None:
         if not isinstance(location, MessageLocationTuple):
             warn(
                 "In pylint 3.0, Messages will only accept a MessageLocationTuple as location parameter",
                 DeprecationWarning,
             )
-            location = location + (None, None)  # type: ignore[assignment] # Temporary fix until deprecation
-        return _MsgBase.__new__(
-            cls,
-            msg_id,
-            symbol,
-            msg,
-            msg_id[0],
-            MSG_TYPES[msg_id[0]],
-            confidence,
-            *location,
-        )
+            location = MessageLocationTuple(
+                location[0],
+                location[1],
+                location[2],
+                location[3],
+                location[4],
+                location[5],
+                None,
+                None,
+            )
+
+        self.msg_id = msg_id
+        self.symbol = symbol
+        self.msg = msg
+        self.C = msg_id[0]
+        self.category = MSG_TYPES[msg_id[0]]
+        self.confidence = confidence or UNDEFINED
+        self.abspath = location.abspath
+        self.path = location.path
+        self.module = location.module
+        self.obj = location.obj
+        self.line = location.line
+        self.column = location.column
+        self.end_line = location.end_line
+        self.end_column = location.end_column
 
     def format(self, template: str) -> str:
         """Format the message according to the given template.
@@ -90,4 +76,4 @@ class Message(_MsgBase):
         The template format is the one of the format method :
         cf. https://docs.python.org/2/library/string.html#formatstrings
         """
-        return template.format(**self._asdict())
+        return template.format(**asdict(self))
diff --git a/pylint/reporters/text.py b/pylint/reporters/text.py
index 347f4d6d2..009582fa0 100644
--- a/pylint/reporters/text.py
+++ b/pylint/reporters/text.py
@@ -14,6 +14,7 @@ import os
 import re
 import sys
 import warnings
+from dataclasses import asdict, fields
 from typing import TYPE_CHECKING, Dict, NamedTuple, Optional, TextIO, cast, overload
 
 from pylint.interfaces import IReporter
@@ -66,6 +67,9 @@ ANSI_COLORS = {
     "white": "37",
 }
 
+MESSAGE_FIELDS = {i.name for i in fields(Message)}
+"""All fields of the Message class."""
+
 
 def _get_ansi_code(msg_style: MessageStyle) -> str:
     """Return ansi escape code corresponding to color and style.
@@ -176,7 +180,7 @@ class TextReporter(BaseReporter):
         # Check to see if all parameters in the template are attributes of the Message
         arguments = re.findall(r"\{(.+?)(:.*)?\}", template)
         for argument in arguments:
-            if argument[0] not in Message._fields:
+            if argument[0] not in MESSAGE_FIELDS:
                 warnings.warn(
                     f"Don't recognize the argument '{argument[0]}' in the --msg-template. "
                     "Are you sure it is supported on the current version of pylint?"
@@ -186,7 +190,7 @@ class TextReporter(BaseReporter):
 
     def write_message(self, msg: Message) -> None:
         """Convenience method to write a formatted message with class default template."""
-        self_dict = msg._asdict()
+        self_dict = asdict(msg)
         for key in ("end_line", "end_column"):
             self_dict[key] = self_dict[key] or ""
 
@@ -316,12 +320,10 @@ class ColorizedTextReporter(TextReporter):
             self._modules.add(msg.module)
         msg_style = self._get_decoration(msg.C)
 
-        msg = msg._replace(
-            **{
-                attr: colorize_ansi(getattr(msg, attr), msg_style)
-                for attr in ("msg", "symbol", "category", "C")
-            }
-        )
+        msg.msg = colorize_ansi(msg.msg, msg_style)
+        msg.symbol = colorize_ansi(msg.symbol, msg_style)
+        msg.category = colorize_ansi(msg.category, msg_style)
+        msg.C = colorize_ansi(msg.C, msg_style)
         self.write_message(msg)
 
 
diff --git a/pylint/testutils/output_line.py b/pylint/testutils/output_line.py
index 4cde92d4f..14d172725 100644
--- a/pylint/testutils/output_line.py
+++ b/pylint/testutils/output_line.py
@@ -99,7 +99,7 @@ class OutputLine(NamedTuple):
         )
 
     @staticmethod
-    def _get_column(column: str) -> int:
+    def _get_column(column: str | int) -> int:
         """Handle column numbers except for python < 3.8.
 
         The ast parser in those versions doesn't return them.