Avoid Object of type PosixPath is not JSON serializable with jinja2 (#…

…2724)

Fixes: #2697

.config/dictionary.txt

@@ -74,6 +74,7 @@ createfile
 darglint
 dataclasses
 dbservers
+deannotate
 debops
 decryptable
 delenv

examples/playbooks/rule-jinja-valid.yml

@@ -26,3 +26,23 @@
       vars:
         ns_vars: {}
         x: "{{ lookup('ansible.builtin.template', 'namespace.yaml.j2', template_vars=ns_vars) | from_yaml }}"
+
+# https://github.com/ansible/ansible-lint/issues/2697
+- name: Test linter
+  hosts: localhost
+  gather_facts: false
+  tasks:
+    - name: Passed linter
+      ansible.builtin.debug:
+        msg: "{{ test | to_json }}"
+      vars:
+        test:
+          one: two
+          param: "{{ ansible_host }}"
+    - name: Failed linter
+      ansible.builtin.debug:
+        msg: "{{ test | to_json }}"
+      vars:
+        test:
+          one: two
+          param: no jinja

src/ansiblelint/rules/jinja.py

@@ -29,6 +29,24 @@
 
 Token = namedtuple("Token", "lineno token_type value")
 
+DEANNOTATE_KEYS = ("__file__", "__line__", "__start_line__", "__end_line__")
+
+
+def deannotate(data: Any) -> Any:
+    """Remove our annotations like __file__ and __line__ and return a JSON serializable object."""
+    if isinstance(data, dict):
+        result = data.copy()
+        for key, value in data.items():
+            if key in DEANNOTATE_KEYS:
+                del result[key]
+            elif isinstance(value, list):
+                for i, item in enumerate(value):
+                    value[i] = deannotate(item)
+            elif isinstance(value, dict):
+                result[key] = deannotate(value)
+        return result
+    return result
+
 
 class JinjaRule(AnsibleLintRule):
     """Rule that looks inside jinja2 templates."""
@@ -62,7 +80,7 @@ def matchtask(  # noqa: C901
                     template(
                         basedir=file.dir if file else ".",
                         value=v,
-                        variables=task.get("vars", {}),
+                        variables=deannotate(task.get("vars", {})),
                         fail_on_error=True,  # we later decide which ones to ignore or not
                     )
                 # ValueError RepresenterError