Improve diagnostic message when failing to load yaml files

Detected while debugging extension diagnostic messages as we spotted
undesired slipping of line/column information inside of the generated
error message.

Related: ansible/vscode-ansible#2005

Author: ssbarnea

examples/load-failure-invalid.yml

@@ -0,0 +1,5 @@
+---
+- aaa: 1
+  bbb: 2
+  c: 3
+foo: bar

src/ansiblelint/runner.py

@@ -44,6 +44,9 @@
     parse_examples_from_plugin,
     template,
 )
+from yaml.scanner import ScannerError
+from ruamel.yaml.parser import ParserError as RuamelParserError
+from yaml.parser import ParserError
 
 if TYPE_CHECKING:
     from collections.abc import Callable, Generator
@@ -213,14 +216,30 @@ def _run(self) -> list[MatchError]:
                 self.lintables.remove(lintable)
                 continue
             if isinstance(lintable.data, States) and lintable.exc:
+                line = 1
+                column = None
+                detail = ""
+                sub_tag = ""
                 lintable.exc.__class__.__name__.lower()
+                message = None
+                if lintable.exc.__cause__ and isinstance(lintable.exc.__cause__, ScannerError | ParserError | RuamelParserError):
+                    sub_tag = "yaml"
+                    if isinstance(lintable.exc.args, tuple):
+                        message = lintable.exc.args[0]
+                    detail = lintable.exc.__cause__.problem
+                    if lintable.exc.__cause__.problem_mark:
+                        line = lintable.exc.__cause__.problem_mark.line + 1
+                        column = lintable.exc.__cause__.problem_mark.column + 1
+
                 matches.append(
                     MatchError(
                         lintable=lintable,
-                        message=str(lintable.exc),
-                        details=str(lintable.exc.__cause__),
+                        message=message or str(lintable.exc),
+                        details=detail or str(lintable.exc.__cause__),
                         rule=self.rules["load-failure"],
-                        tag=f"load-failure[{lintable.exc.__class__.__name__.lower()}]",
+                        lineno=line,
+                        column=column,
+                        tag=f"load-failure[{sub_tag or lintable.exc.__class__.__name__.lower()}]",
                     ),
                 )
                 lintable.stop_processing = True

src/ansiblelint/schemas/__store__.json

@@ -24,7 +24,7 @@
     "url": "https://raw.githubusercontent.com/ansible/ansible-lint/main/src/ansiblelint/schemas/inventory.json"
   },
   "meta": {
-    "etag": "ba724ad96ccb630237b908377c31796a1208265731b4b8a8fa91ffb7e52c611b",
+    "etag": "50a33e03b769d4574f20f192ce37dcb694361a8b30e030b2c1274f393e6595e4",
     "url": "https://raw.githubusercontent.com/ansible/ansible-lint/main/src/ansiblelint/schemas/meta.json"
   },
   "meta-runtime": {

src/ansiblelint/utils.py

@@ -1160,8 +1160,8 @@ def construct_mapping(
         yaml.constructor.ConstructorError,
         ruamel.yaml.parser.ParserError,
     ) as exc:
-        msg = f"Failed to load YAML file: {lintable.path}"
-        raise RuntimeError(msg) from exc
+        msg = "Failed to load YAML file"
+        raise RuntimeError(msg, lintable.path) from exc
 
     if len(result) == 0:
         return None  # empty documents

test/test_runner.py

@@ -240,6 +240,23 @@ def test_runner_not_found(default_rules_collection: RulesCollection) -> None:
     assert len(result) == 1
     assert result[0].tag == "load-failure[not-found]"
 
+def test_runner_load_failure_yaml(default_rules_collection: RulesCollection) -> None:
+    """Ensure load-failure[yaml] work as expected."""
+    checked_files: set[Lintable] = set()
+
+    filename = Path("examples/load-failure-invalid.yml").resolve()
+    runner = Runner(
+        filename,
+        rules=default_rules_collection,
+        verbosity=0,
+        checked_files=checked_files,
+    )
+    result = runner.run()
+    assert len(runner.checked_files) == 1
+    assert len(result) == 1
+    assert result[0].tag == "load-failure[yaml]"
+    assert result[0].lineno == 5
+    assert result[0].column == 1
 
 def test_runner_tmp_file(
     tmp_path: Path,

tox.ini

@@ -56,7 +56,7 @@ set_env =
     PIP_CONSTRAINT = {tox_root}/.config/constraints.txt
     PIP_DISABLE_PIP_VERSION_CHECK = 1
     PRE_COMMIT_COLOR = always
-    PYTEST_REQPASS = 908
+    PYTEST_REQPASS = 909
     UV_CONSTRAINT = {tox_root}/.config/constraints.txt
     deps, devel, hook, lint, pkg, pre, py310, schemas: PIP_CONSTRAINT = /dev/null
     deps, devel, hook, lint, pkg, pre, py310, schemas: UV_CONSTRAINT = /dev/null