Add unit tests for loader glob skip guard (from PR #4852)

tests/test_loader_glob_skip.py

@@ -0,0 +1,152 @@
+"""Tests that HfFileSystem().glob() is skipped when is_model or is_peft is False.
+
+The glob calls in FastLanguageModel.from_pretrained and FastModel.from_pretrained
+exist solely to detect repos with both config.json and adapter_config.json. When
+either AutoConfig or PeftConfig fails to load, the glob cannot find both files,
+so calling it is redundant and risks hanging on slow networks.
+"""
+
+import os
+import unittest
+from unittest.mock import MagicMock, patch
+
+
+class TestGlobSkippedWhenNotBothConfigs(unittest.TestCase):
+    """Verify HfFileSystem.glob is not called when is_model or is_peft is False."""
+
+    def _run_both_exist_block(
+        self, is_model, is_peft, supports_llama32, model_name, is_local_dir = False
+    ):
+        """Simulate the both_exist detection block from loader.py.
+
+        This mirrors the exact logic at lines 500-517 / 1276-1292 of loader.py.
+        Returns (both_exist, glob_called).
+        """
+        from unittest.mock import MagicMock
+
+        both_exist = (is_model and is_peft) and not supports_llama32
+        glob_mock = MagicMock(
+            return_value = [
+                f"{model_name}/config.json",
+                f"{model_name}/adapter_config.json",
+            ]
+        )
+
+        # This mirrors the guarded block in loader.py
+        if supports_llama32 and is_model and is_peft:
+            if is_local_dir:
+                # Local path branch — would use os.path.exists in real code
+                both_exist = True  # simulate both files present locally
+            else:
+                files = glob_mock(f"{model_name}/*.json")
+                files = list(os.path.split(x)[-1] for x in files)
+                if (
+                    sum(x == "adapter_config.json" or x == "config.json" for x in files)
+                    >= 2
+                ):
+                    both_exist = True
+
+        return both_exist, glob_mock.called
+
+    # --- Cases where glob should NOT be called ---
+
+    def test_glob_skipped_when_is_model_false(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = False,
+            is_peft = True,
+            supports_llama32 = True,
+            model_name = "org/some-adapter",
+        )
+        self.assertFalse(glob_called, "glob should not be called when is_model=False")
+        self.assertFalse(both_exist)
+
+    def test_glob_skipped_when_is_peft_false(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = True,
+            is_peft = False,
+            supports_llama32 = True,
+            model_name = "org/some-model",
+        )
+        self.assertFalse(glob_called, "glob should not be called when is_peft=False")
+        self.assertFalse(both_exist)
+
+    def test_glob_skipped_when_both_false(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = False,
+            is_peft = False,
+            supports_llama32 = True,
+            model_name = "org/bad-repo",
+        )
+        self.assertFalse(glob_called, "glob should not be called when both are False")
+        self.assertFalse(both_exist)
+
+    def test_glob_skipped_when_supports_llama32_false(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = True,
+            is_peft = True,
+            supports_llama32 = False,
+            model_name = "org/some-model",
+        )
+        self.assertFalse(
+            glob_called, "glob should not be called when SUPPORTS_LLAMA32=False"
+        )
+        # both_exist is set by the old-style check: (is_model and is_peft) and not SUPPORTS_LLAMA32
+        self.assertTrue(both_exist)
+
+    # --- Cases where glob SHOULD be called ---
+
+    def test_glob_called_when_both_true_and_supports_llama32(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = True,
+            is_peft = True,
+            supports_llama32 = True,
+            model_name = "org/mixed-repo",
+        )
+        self.assertTrue(
+            glob_called, "glob should be called when is_model and is_peft are both True"
+        )
+        self.assertTrue(both_exist)
+
+    def test_local_dir_skips_glob(self):
+        both_exist, glob_called = self._run_both_exist_block(
+            is_model = True,
+            is_peft = True,
+            supports_llama32 = True,
+            model_name = "/local/path/to/model",
+            is_local_dir = True,
+        )
+        self.assertFalse(glob_called, "glob should not be called for local directories")
+        self.assertTrue(both_exist)
+
+
+class TestLoaderSourceHasGuard(unittest.TestCase):
+    """Verify the actual loader.py source code has the is_model/is_peft guard."""
+
+    def test_loader_source_has_guard(self):
+        """Check that both SUPPORTS_LLAMA32 checks in loader.py include is_model and is_peft."""
+        loader_path = os.path.join(
+            os.path.dirname(__file__), os.pardir, "unsloth", "models", "loader.py"
+        )
+        with open(loader_path) as f:
+            source = f.read()
+
+        # Find all lines with the SUPPORTS_LLAMA32 check near glob usage
+        lines = source.splitlines()
+        guard_lines = [
+            line.strip()
+            for line in lines
+            if "SUPPORTS_LLAMA32" in line and "if " in line and "is_model" in line
+        ]
+        # There should be exactly 2 guarded checks (one per from_pretrained method)
+        self.assertEqual(
+            len(guard_lines),
+            2,
+            f"Expected 2 guarded SUPPORTS_LLAMA32 checks with is_model/is_peft, found {len(guard_lines)}: {guard_lines}",
+        )
+        for line in guard_lines:
+            self.assertIn("is_model", line)
+            self.assertIn("is_peft", line)
+
+
+if __name__ == "__main__":
+    unittest.main()