Pass quote=False to html.escape in the JSON reporter

Close #2769

ChangeLog

@@ -2,6 +2,15 @@
 Pylint's ChangeLog
 ------------------
 
+What's New in Pylint 2.3.1?
+===========================
+
+Release date: TBA
+
+* Properly pass `quote=False` to `html.escape` in the JSON reporter
+
+  Close #2769
+
 What's New in Pylint 2.3.0?
 ===========================
 

pylint/reporters/json.py

@@ -39,8 +39,7 @@ def handle_message(self, msg):
                 "column": msg.column,
                 "path": msg.path,
                 "symbol": msg.symbol,
-                # pylint: disable=deprecated-method; deprecated since 3.2.
-                "message": html.escape(msg.msg or ""),
+                "message": html.escape(msg.msg or "", quote=False),
                 "message-id": msg.msg_id,
             }
         )

pylint/test/regrtest_data/unused_variable.py

@@ -0,0 +1,6 @@
+# pylint: disable=missing-docstring
+
+def test():
+    variable = ''
+    variable2 = None
+    return variable2

pylint/test/test_self.py

@@ -433,6 +433,28 @@ def test_json_report_when_file_is_missing(self):
             assert message[key] == value
         assert message["message"].startswith("No module named")
 
+    def test_json_report_does_not_escape_quotes(self):
+        out = StringIO()
+        module = join(HERE, "regrtest_data", "unused_variable.py")
+        self._runtest([module], code=4, reporter=JSONReporter(out))
+        output = json.loads(out.getvalue())
+        assert isinstance(output, list)
+        assert len(output) == 1
+        assert isinstance(output[0], dict)
+        expected = {
+            "symbol": "unused-variable",
+            "module": "unused_variable",
+            "column": 4,
+            "message": "Unused variable 'variable'",
+            "message-id": "W0612",
+            "line": 4,
+            "type": "warning",
+        }
+        message = output[0]
+        for key, value in expected.items():
+            assert key in message
+            assert message[key] == value
+
     def test_information_category_disabled_by_default(self):
         expected = "Your code has been rated at 10.00/10"
         path = join(HERE, "regrtest_data", "meta.py")