Avoid reporting loading errors with vaulted files

examples/playbooks/vars/not_decryptable.yml

@@ -0,0 +1,10 @@
+$ANSIBLE_VAULT;1.1;AES256
+35366433323361393130396530643233373262666636646439303032366431303363316232313738
+3738636130636431623936303932306430316635663136610a353737333966353462333532393631
+36613030643762636138613734313862333165346464626461313361353732336131633137653865
+3862386136386137650a303433643531613337393735633338383163353737656339653134346363
+63613436333937313738633437373566333065663662643664643261313366323236356364316663
+62336264666464323066336365616634626336616537646336656266343562336533343732613539
+61643661303566313664313164623731316236666235656337363632393665353536303730666532
+64666639306361653963363462393966623763626566613831613739333666333665343734333630
+63623730623033346163393834396639383234393637653733396466316132663131

src/ansiblelint/rules/__init__.py

@@ -143,6 +143,8 @@ def matchyaml(self, file: Lintable) -> List[MatchError]:
         # file contains a single string. YAML spec allows this but we consider
         # this an fatal error.
         if isinstance(yaml, str):
+            if yaml.startswith('$ANSIBLE_VAULT'):
+                return []
             return [MatchError(filename=str(file.path), rule=LoadingFailureRule())]
         if not yaml:
             return matches

test/TestExamples.py

@@ -46,3 +46,11 @@ def test_example_custom_module(default_rules_collection):
         'examples/playbooks/custom_module.yml', rules=default_rules_collection
     ).run()
     assert len(result) == 0
+
+
+def test_full_vault(default_rules_collection):
+    """custom_module.yml is expected to pass."""
+    result = Runner(
+        'examples/playbooks/vars/not_decryptable.yml', rules=default_rules_collection
+    ).run()
+    assert len(result) == 0