var-naming now prevents use of Ansible reserved names

Related: #3456

examples/playbooks/vars/rule_var_naming_fail.yml

@@ -6,5 +6,6 @@ this_is_valid: # valid because content is a dict, not a variable
 ALL_CAPS_ARE_BAD_TOO: ... # invalid
 "{{ 'test_' }}var": "value" # noqa: schema
 CamelCaseButErrorIgnored: true # noqa: var-naming
-assert: true # invalid due to reserved keyword
+assert: true # invalid due to being Python reserved keyword
 é: true # invalid due to non-ascii character
+hosts: true # invalid as being Ansible reserved name

src/ansiblelint/rules/var_naming.md

@@ -18,6 +18,7 @@ Possible errors messages:
 - `var-naming[pattern]`: Variables names should match ... regex.
 - `var-naming[no-role-prefix]`: Variables names from within roles should use
   `role_name_` as a prefix.
+- `var-naming[no-reserved]`: Variables names must not be Ansible reserved names.
 
 ## Settings
 
@@ -38,6 +39,7 @@ var_naming_pattern: "^[a-z_][a-z0-9_]*$"
     CamelCase: true # <- Contains a mix of lowercase and uppercase characters.
     ALL_CAPS: bar # <- Contains only uppercase characters.
     v@r!able: baz # <- Contains special characters.
+    hosts: [] # <- hosts is an Ansible reserved name
 ```
 
 ## Correct Code
@@ -50,6 +52,7 @@ var_naming_pattern: "^[a-z_][a-z0-9_]*$"
     lowercase: true # <- Contains only lowercase characters.
     no_caps: bar # <- Does not contains uppercase characters.
     variable: baz # <- Does not contain special characters.
+    my_hosts: [] # <- Does not use a reserved names.
 ```
 
 [cop]: https://redhat-cop.github.io/automation-good-practices/#_naming_things

src/ansiblelint/rules/var_naming.py

@@ -7,6 +7,7 @@
 from typing import TYPE_CHECKING, Any
 
 from ansible.parsing.yaml.objects import AnsibleUnicode
+from ansible.vars.reserved import get_reserved_names
 
 from ansiblelint.config import options
 from ansiblelint.constants import LINE_NUMBER_KEY, RC
@@ -31,6 +32,7 @@ class VariableNamingRule(AnsibleLintRule):
     needs_raw_task = True
     re_pattern_str = options.var_naming_pattern or "^[a-z_][a-z0-9_]*$"
     re_pattern = re.compile(re_pattern_str)
+    reserved_names = get_reserved_names()
 
     # pylint: disable=too-many-return-statements)
     def get_var_naming_matcherror(
@@ -52,14 +54,21 @@ def get_var_naming_matcherror(
         except UnicodeEncodeError:
             return MatchError(
                 tag="var-naming[non-ascii]",
-                message="Variables names must be ASCII.",
+                message=f"Variables names must be ASCII. ({ident})",
                 rule=self,
             )
 
         if keyword.iskeyword(ident):
             return MatchError(
                 tag="var-naming[no-keyword]",
-                message="Variables names must not be Python keywords.",
+                message=f"Variables names must not be Python keywords. ({ident})",
+                rule=self,
+            )
+
+        if ident in self.reserved_names:
+            return MatchError(
+                tag="var-naming[no-reserved]",
+                message=f"Variables names must not be Ansible reserved names. ({ident})",
                 rule=self,
             )
 
@@ -74,7 +83,7 @@ def get_var_naming_matcherror(
         if not bool(self.re_pattern.match(ident)):
             return MatchError(
                 tag="var-naming[pattern]",
-                message=f"Variables names should match {self.re_pattern_str} regex.",
+                message=f"Variables names should match {self.re_pattern_str} regex. ({ident})",
                 rule=self,
             )
 
@@ -239,6 +248,7 @@ def test_invalid_var_name_varsfile(
             ("var-naming[no-jinja]", 7),
             ("var-naming[no-keyword]", 9),
             ("var-naming[non-ascii]", 10),
+            ("var-naming[no-reserved]", 11),
         )
         assert len(results) == len(expected_errors)
         for idx, result in enumerate(results):
@@ -255,3 +265,12 @@ def test_var_naming_with_pattern() -> None:
         )
         assert result.returncode == RC.SUCCESS
         assert "var-naming" not in result.stdout
+
+    def test_var_naming_reserved() -> None:
+        """Tests out ability to detect reserved names."""
+        from ansible.vars.reserved import get_reserved_names
+
+        breakpoint()
+
+        x = get_reserved_names()
+        assert x == []