Do inventory parsing non-multithreaded

src/ansiblelint/runner.py

@@ -246,6 +246,7 @@ def _run(self) -> list[MatchError]:
             def worker(lintable: Lintable) -> list[MatchError]:
                 return self._get_ansible_syntax_check_matches(
                     lintable=lintable,
+                    inventory_opts=inventory_opts,
                     app=self.app,
                 )
 
@@ -257,6 +258,15 @@ def worker(lintable: Lintable) -> list[MatchError]:
                     continue
                 files.append(lintable)
 
+            inventory_opts = [
+                inventory_opt
+                for inventory_opts in [
+                    ("-i", inventory_file)
+                    for inventory_file in self._get_inventory_files(self.app)
+                ]
+                for inventory_opt in inventory_opts
+            ]
+
             # avoid resource leak warning, https://github.com/python/cpython/issues/90549
             # pylint: disable=unused-variable
             global_resource = multiprocessing.Semaphore()  # noqa: F841
@@ -304,6 +314,7 @@ def worker(lintable: Lintable) -> list[MatchError]:
     def _get_ansible_syntax_check_matches(
         self,
         lintable: Lintable,
+        inventory_opts: list[str],
         app: App,
     ) -> list[MatchError]:
         """Run ansible syntax check and return a list of MatchError(s)."""
@@ -346,14 +357,7 @@ def _get_ansible_syntax_check_matches(
                 playbook_path = str(lintable.path.expanduser())
             cmd = [
                 "ansible-playbook",
-                *[
-                    inventory_opt
-                    for inventory_opts in [
-                        ("-i", inventory_file)
-                        for inventory_file in self._get_inventory_files(app)
-                    ]
-                    for inventory_opt in inventory_opts
-                ],
+                *inventory_opts,
                 "--syntax-check",
                 playbook_path,
             ]

test/test_app.py

@@ -97,3 +97,26 @@ def test_with_inventory_via_ansible_cfg(tmp_path: Path) -> None:
 
     result = run_ansible_lint(lintable.filename, cwd=tmp_path)
     assert result.returncode == RC.SUCCESS
+
+
+def test_with_inventory_concurrent_syntax_checks(tmp_path: Path) -> None:
+    """Validate using inventory file with concurrent syntax checks aren't faulty."""
+    (tmp_path / "ansible.cfg").write_text("[defaults]\ninventory = foo\n")
+    (tmp_path / "foo").write_text("[group_name]\nhost1\nhost2\n")
+    lintable1 = Lintable(tmp_path / "playbook1.yml")
+    lintable2 = Lintable(tmp_path / "playbook2.yml")
+    lintable1.content = "---\n- name: Test\n  hosts:\n    - group_name\n  serial: \"{{ batch | default(groups['group_name'] | length) }}\"\n"
+    lintable2.content = "---\n- name: Test\n  hosts:\n    - group_name\n  serial: \"{{ batch | default(groups['group_name'] | length) }}\"\n"
+    lintable1.kind = "playbook"
+    lintable2.kind = "playbook"
+    lintable1.write(force=True)
+    lintable2.write(force=True)
+
+    counter = 0
+    while counter < 3:
+        result = run_ansible_lint(lintable1.filename, lintable2.filename, cwd=tmp_path)
+        assert result.returncode == RC.SUCCESS
+        # AttributeError err is expected to look like what's reported here,
+        # https://github.com/ansible/ansible-lint/issues/4446.
+        assert "AttributeError" not in result.stderr
+        counter += 1

tox.ini

@@ -75,7 +75,7 @@ setenv =
   PRE_COMMIT_COLOR = always
   # Number of expected test passes, safety measure for accidental skip of
   # tests. Update value if you add/remove tests. (tox-extra)
-  PYTEST_REQPASS = 901
+  PYTEST_REQPASS = 902
   FORCE_COLOR = 1
   pre: PIP_PRE = 1
 allowlist_externals =