Fix `filter_models` (#29710)

* update

* update

* update

* check

---------
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

utils/tests_fetcher.py

@@ -68,6 +68,10 @@ PATH_TO_EXAMPLES = PATH_TO_REPO / "examples"
 PATH_TO_TRANFORMERS = PATH_TO_REPO / "src/transformers"
 PATH_TO_TESTS = PATH_TO_REPO / "tests"
 
+# The value is just a heuristic to determine if we `guess` all models are impacted.
+# This variable has effect only if `filter_models=False`.
+NUM_MODELS_TO_TRIGGER_FULL_CI = 30
+
 # List here the models to always test.
 IMPORTANT_MODELS = [
     "auto",
@@ -1064,10 +1068,18 @@ def infer_tests_to_run(
     impacted_files = sorted(set(impacted_files))
     print(f"\n### IMPACTED FILES ###\n{_print_list(impacted_files)}")
 
+    model_impacted = {"/".join(x.split("/")[:3]) for x in impacted_files if x.startswith("tests/models/")}
+
     # Grab the corresponding test files:
     if any(x in modified_files for x in ["setup.py", ".circleci/create_circleci_config.py"]):
         test_files_to_run = ["tests", "examples"]
         repo_utils_launch = True
+    elif not filter_models and len(model_impacted) >= NUM_MODELS_TO_TRIGGER_FULL_CI:
+        print(
+            f"More than {NUM_MODELS_TO_TRIGGER_FULL_CI - 1} models are impacted and `filter_models=False`. CI is configured to test everything."
+        )
+        test_files_to_run = ["tests", "examples"]
+        repo_utils_launch = True
     else:
         # All modified tests need to be run.
         test_files_to_run = [
@@ -1244,7 +1256,7 @@ if __name__ == "__main__":
                     args.output_file,
                     diff_with_last_commit=diff_with_last_commit,
                     json_output_file=args.json_output_file,
-                    filter_models=(not commit_flags["no_filter"] or is_main_branch),
+                    filter_models=(not (commit_flags["no_filter"] or is_main_branch)),
                 )
                 filter_tests(args.output_file, ["repo_utils"])
             except Exception as e: