fix(kotlin): parse ktlint --reporter=json output correctly

desloppify/languages/_framework/generic_parts/parsers.py

@@ -181,6 +181,35 @@ def parse_eslint(output: str, scan_path: Path) -> list[dict]:
     return entries
 
 
+def parse_ktlint(output: str, scan_path: Path) -> list[dict]:
+    """Parse ktlint `--reporter=json` output.
+
+    Shape: ``[{"file": ..., "errors": [{"line", "column", "message", "rule"}]}]``.
+    This differs from the generic flat ``json`` format (which expects
+    top-level ``file``/``line``/``message`` keys per entry) and from the
+    ESLint format (which nests under ``filePath``/``messages``), so it needs
+    its own parser rather than reusing either.
+    """
+    del scan_path
+    entries: list[dict] = []
+    data = _load_json_output(output, parser_name="ktlint")
+    for fobj in data if isinstance(data, list) else []:
+        if not isinstance(fobj, dict):
+            continue
+        filepath = fobj.get("file", "")
+        for err in fobj.get("errors") or []:
+            if not isinstance(err, dict):
+                continue
+            line = _coerce_line(err.get("line", 0))
+            message = err.get("message", "")
+            rule = err.get("rule", "")
+            if rule:
+                message = f"{message} ({rule})"
+            if filepath and message and line is not None:
+                entries.append({"file": str(filepath), "line": line, "message": str(message)})
+    return entries
+
+
 def parse_phpstan(output: str, scan_path: Path) -> list[dict]:
     """Parse PHPStan JSON: ``{"files": {"<path>": {"messages": [{"message": "...", "line": 42}]}}}``."""
     del scan_path
@@ -314,6 +343,7 @@ def parse_air(output: str, scan_path: Path) -> list[dict]:
     "phpstan": parse_phpstan,
     "rubocop": parse_rubocop,
     "cargo": parse_cargo,
+    "ktlint": parse_ktlint,
     "eslint": parse_eslint,
     "next_lint": parse_next_lint,
     "air": parse_air,
@@ -332,6 +362,7 @@ def parse_air(output: str, scan_path: Path) -> list[dict]:
     "parse_gnu",
     "parse_golangci",
     "parse_json",
+    "parse_ktlint",
     "parse_phpstan",
     "parse_next_lint",
     "parse_rubocop",

desloppify/languages/_framework/generic_support/core.py

@@ -26,6 +26,7 @@
     parse_gnu,
     parse_golangci,
     parse_json,
+    parse_ktlint,
     parse_rubocop,
 )
 from desloppify.languages._framework.generic_parts.tool_factories import (
@@ -178,5 +179,6 @@ def generic_lang(
     "parse_gnu",
     "parse_golangci",
     "parse_json",
+    "parse_ktlint",
     "parse_rubocop",
 ]

desloppify/languages/kotlin/__init__.py

@@ -10,7 +10,7 @@
         {
             "label": "ktlint",
             "cmd": "ktlint --reporter=json",
-            "fmt": "json",
+            "fmt": "ktlint",
             "id": "ktlint_violation",
             "tier": 2,
             "fix_cmd": "ktlint --format",

desloppify/tests/lang/common/test_generic_plugin.py

@@ -20,6 +20,7 @@
     parse_gnu,
     parse_golangci,
     parse_json,
+    parse_ktlint,
     parse_rubocop,
 )
 from desloppify.languages._framework.generic_parts.tool_factories import make_detect_fn
@@ -234,6 +235,59 @@ def test_invalid_json(self):
             parse_eslint("not json", Path("."))
 
 
+class TestParseKtlint:
+    def test_extracts_errors_with_rule_suffix(self):
+        payload = [
+            {
+                "file": "src/main/Foo.kt",
+                "errors": [
+                    {
+                        "line": 10,
+                        "column": 5,
+                        "message": "Newline expected",
+                        "rule": "standard:class-signature",
+                    }
+                ],
+            }
+        ]
+        entries = parse_ktlint(json.dumps(payload), Path("."))
+        assert entries == [
+            {
+                "file": "src/main/Foo.kt",
+                "line": 10,
+                "message": "Newline expected (standard:class-signature)",
+            }
+        ]
+
+    def test_handles_multiple_files_and_errors(self):
+        payload = [
+            {"file": "a.kt", "errors": [{"line": 1, "message": "m1", "rule": "r1"}]},
+            {
+                "file": "b.kt",
+                "errors": [
+                    {"line": 2, "message": "m2", "rule": "r2"},
+                    {"line": 3, "message": "m3", "rule": "r3"},
+                ],
+            },
+        ]
+        entries = parse_ktlint(json.dumps(payload), Path("."))
+        assert len(entries) == 3
+        assert entries[0]["file"] == "a.kt"
+        assert entries[1]["file"] == "b.kt" and entries[1]["line"] == 2
+        assert entries[2]["line"] == 3
+
+    def test_file_with_no_errors_yields_nothing(self):
+        payload = [{"file": "clean.kt", "errors": []}]
+        assert parse_ktlint(json.dumps(payload), Path(".")) == []
+
+    def test_empty_array(self):
+        assert parse_ktlint("[]", Path(".")) == []
+
+    def test_invalid_json(self):
+        with pytest.raises(ToolParserError):
+            parse_ktlint("not json", Path("."))
+
+
 class TestParsePhpstan:
     def test_extracts_messages(self):
         data = {