feat: detect missing prefix in role's handlers vars (#4816)

Author: cavcrosby

.config/dictionary.txt

@@ -91,6 +91,7 @@ switchport
 sysvinit
 taskshandlers
 testinfra
+thefoo
 timesyncd
 tmpfs
 tomlsort

examples/roles/role_vars_prefix_detection/handlers/main.yml

@@ -0,0 +1,18 @@
+---
+- name: Echo thefoo
+  ansible.builtin.command: echo thefoo
+  changed_when: true
+  register: thefoo
+
+- name: Echo thebar
+  ansible.builtin.command: echo thebar
+  changed_when: true
+  register: role_vars_prefix_detection_thebar
+
+- name: Test ansible.builtin.set_fact without role prefix
+  ansible.builtin.set_fact:
+    foo: bar
+
+- name: Test set_fact with role prefix
+  ansible.builtin.set_fact:
+    role_vars_prefix_detection_foo: bar

src/ansiblelint/rules/var_naming.py

@@ -250,8 +250,8 @@ def matchtask(
         results = []
         task_prefix = Prefix()
         role_prefix = Prefix()
-        if file and file.parent and file.parent.kind == "role":
-            role_prefix = Prefix(file.parent.path.name)
+        if file and file.role:
+            role_prefix = Prefix(file.role)
         ansible_module = task["action"]["__ansible_module__"]
         # If the task uses the 'vars' section to set variables
         # only check role prefix for include_role and import_role tasks 'vars'
@@ -426,7 +426,7 @@ def test_var_naming_with_role_prefix(
             Lintable("examples/roles/role_vars_prefix_detection"),
             rules=default_rules_collection,
         ).run()
-        assert len(results) == 2
+        assert len(results) == 4
         for result in results:
             assert result.tag == "var-naming[no-role-prefix]"