Add ability to ignore jinja2 templates

Fixes issue where jinja2 templated YAML files would endup raising
errors, as the YAML loader would have failed to load them.

.pre-commit-config.yaml

@@ -46,6 +46,10 @@ repos:
   rev: v1.26.0
   hooks:
   - id: yamllint
+    exclude: >
+      (?x)^(
+        examples/other/some.j2.yaml
+      )$
     files: \.(yaml|yml)$
     types: [file, yaml]
     entry: yamllint --strict

examples/other/some.j2.yaml

@@ -0,0 +1,2 @@
+# Used to validate that a templated YAML file does not confuse the linter
+{% include 'port.j2' %}

src/ansiblelint/config.py

@@ -13,6 +13,8 @@
 
 DEFAULT_KINDS = [
     # Do not sort this list, order matters.
+    {"jinja2": "**/*.j2"},  # jinja2 templates are not always parsable as something else
+    {"jinja2": "**/*.j2.*"},
     {"requirements": "**/meta/requirements.yml"},  # v1 only
     # https://docs.ansible.com/ansible/latest/dev_guide/collections_galaxy_meta.html
     {"galaxy": "**/galaxy.yml"},  # Galaxy collection meta
@@ -40,6 +42,10 @@
     # These assignations are only for internal use and are only inspired by
     # MIME/IANA model. Their purpose is to be able to process a file based on
     # it type, including generic processing of text files using the prefix.
+    {
+        "text/jinja2": "**/*.j2"
+    },  # jinja2 templates are not always parsable as something else
+    {"text/jinja2": "**/*.j2.*"},
     {"text/json": "**/*.json"},  # standardized
     {"text/markdown": "**/*.md"},  # https://tools.ietf.org/html/rfc7763
     {"text/rst": "**/*.rst"},  # https://en.wikipedia.org/wiki/ReStructuredText

src/ansiblelint/rules/__init__.py

@@ -89,7 +89,11 @@ def matchlines(self, file: "Lintable") -> List[MatchError]:
     # https://github.com/ansible-community/ansible-lint/issues/744
     def matchtasks(self, file: Lintable) -> List[MatchError]:
         matches: List[MatchError] = []
-        if not self.matchtask or file.kind not in ['handlers', 'tasks', 'playbook']:
+        if (
+            not self.matchtask
+            or file.kind not in ['handlers', 'tasks', 'playbook']
+            or file.base_kind != 'text/yaml'
+        ):
             return matches
 
         yaml = ansiblelint.utils.parse_yaml_linenumbers(file)
@@ -136,7 +140,7 @@ def _matchplay_linenumber(play, optional_linenumber):
 
     def matchyaml(self, file: Lintable) -> List[MatchError]:
         matches: List[MatchError] = []
-        if not self.matchplay:
+        if not self.matchplay or file.base_kind != 'text/yaml':
             return matches
 
         yaml = ansiblelint.utils.parse_yaml_linenumbers(file)

src/ansiblelint/utils.py

@@ -737,6 +737,7 @@ def construct_mapping(node, deep=False):
         loader.construct_mapping = construct_mapping
         data = loader.get_single_data()
     except (yaml.parser.ParserError, yaml.scanner.ScannerError) as e:
+        logging.exception(e)
         raise SystemExit("Failed to parse YAML in %s: %s" % (lintable.path, str(e)))
     return data
 

test/TestExamples.py

@@ -64,3 +64,4 @@ def test_custom_kinds():
     # .yaml-too is not a recognized extension and unless is manually defined
     # in our .ansible-lint config, the test would not identify it as yaml file.
     assert "Examining examples/other/some.yaml-too of type yaml" in result.stderr
+    assert "Examining examples/other/some.j2.yaml of type jinja2" in result.stderr

test/TestUtils.py

@@ -365,6 +365,10 @@ def test_is_playbook():
             "tasks",
         ),  # relative path involved
         ("galaxy.yml", "galaxy"),
+        ("foo.j2.yml", "jinja2"),
+        ("foo.yml.j2", "jinja2"),
+        ("foo.j2.yaml", "jinja2"),
+        ("foo.yaml.j2", "jinja2"),
     ),
 )
 def test_default_kinds(monkeypatch, path: str, kind: FileType) -> None: