[JsonReporter] Add serialization functions to JsonReporter

Author: Pierre-Sassoulas

pylint/reporters/json_reporter.py

@@ -9,7 +9,10 @@
 import json
 from typing import TYPE_CHECKING
 
+from pylint.interfaces import UNDEFINED
+from pylint.message import Message
 from pylint.reporters.base_reporter import BaseReporter
+from pylint.typing import MessageLocationTuple
 
 if TYPE_CHECKING:
     from pylint.lint.pylinter import PyLinter
@@ -24,24 +27,47 @@ class JSONReporter(BaseReporter):
 
     def display_messages(self, layout: Section | None) -> None:
         """Launch layouts display."""
-        json_dumpable = [
-            {
-                "type": msg.category,
-                "module": msg.module,
-                "obj": msg.obj,
-                "line": msg.line,
-                "column": msg.column,
-                "endLine": msg.end_line,
-                "endColumn": msg.end_column,
-                "path": msg.path,
-                "symbol": msg.symbol,
-                "message": msg.msg or "",
-                "message-id": msg.msg_id,
-            }
-            for msg in self.messages
-        ]
+        json_dumpable = [self.serialize(message) for message in self.messages]
         print(json.dumps(json_dumpable, indent=4), file=self.out)
 
+    @staticmethod
+    def serialize(message: Message) -> dict[str, int | str | None]:
+        # TODO (3.0) add abspath and confidence
+        return {
+            "type": message.category,
+            "module": message.module,
+            "obj": message.obj,
+            "line": message.line,
+            "column": message.column,
+            "endLine": message.end_line,
+            "endColumn": message.end_column,
+            "path": message.path,
+            "symbol": message.symbol,
+            "message": message.msg or "",
+            "message-id": message.msg_id,
+        }
+
+    @staticmethod
+    def deserialize(message_as_json: dict) -> Message:
+        return Message(
+            msg_id=message_as_json["message-id"],
+            symbol=message_as_json["symbol"],
+            msg=message_as_json["message"],
+            location=MessageLocationTuple(
+                # TODO (3.0) abspath is not available in json export
+                abspath=message_as_json["path"],
+                path=message_as_json["path"],
+                module=message_as_json["module"],
+                obj=message_as_json["obj"],
+                line=message_as_json["line"],
+                column=message_as_json["column"],
+                end_line=message_as_json["endLine"],
+                end_column=message_as_json["endColumn"],
+            ),
+            # TODO (3.0) confidence is not available in json export
+            confidence=UNDEFINED,
+        )
+
     def display_reports(self, layout: Section) -> None:
         """Don't do anything in this reporter."""
 

tests/reporters/unittest_json_reporter.py

@@ -10,10 +10,15 @@
 from io import StringIO
 from typing import Any
 
+import pytest
+
 from pylint import checkers
+from pylint.interfaces import UNDEFINED
 from pylint.lint import PyLinter
+from pylint.message import Message
 from pylint.reporters import JSONReporter
 from pylint.reporters.ureports.nodes import EvaluationSection
+from pylint.typing import MessageLocationTuple
 
 expected_score_message = "Expected score message"
 
@@ -98,3 +103,35 @@ def get_linter_result(score: bool, message: dict[str, Any]) -> list[dict[str, An
     reporter.display_messages(None)
     report_result = json.loads(output.getvalue())
     return report_result
+
+
+@pytest.mark.parametrize(
+    "message",
+    [
+        pytest.param(
+            Message(
+                msg_id="C0111",
+                symbol="missing-docstring",
+                location=MessageLocationTuple(
+                    # abstpath and path must be equal because one of them is removed
+                    # in the JsonReporter
+                    abspath=__file__,
+                    path=__file__,
+                    module="unittest_json_reporter",
+                    obj="obj",
+                    line=1,
+                    column=3,
+                    end_line=3,
+                    end_column=5,
+                ),
+                msg="This is the actual message",
+                confidence=UNDEFINED,
+            ),
+            id="everything-defined",
+        )
+    ],
+)
+def test_serialize_deserialize(message):
+    # TODO (3.0): Add confidence handling, add path/abspath handling
+    json_message = JSONReporter.serialize(message)
+    assert message == JSONReporter.deserialize(json_message)