fix: isolate extra unet paths from checkpoints to prevent type misclassification

Refactor _prepare_checkpoint_paths() to return a tuple instead of having
side effects on instance variables. This prevents extra unet paths from
being incorrectly classified as checkpoints when processing extra paths.

- Changed return type from List[str] to Tuple[List[str], List[str], List[str]]
  (all_paths, checkpoint_roots, unet_roots)
- Updated _init_checkpoint_paths() and _apply_library_paths() callers
- Fixed extra paths processing to properly isolate main and extra roots
- Updated test_checkpoint_path_overlap.py tests for new API

This ensures models in extra unet paths are correctly identified as
diffusion_model type and don't appear in checkpoints list.

tests/config/test_checkpoint_path_overlap.py

@@ -36,8 +36,8 @@ class TestCheckpointPathOverlap:
             config._preview_root_paths = set()
             config._cached_fingerprint = None
 
-            # Call the method under test
-            result = config._prepare_checkpoint_paths(
+            # Call the method under test - now returns a tuple
+            all_paths, checkpoint_roots, unet_roots = config._prepare_checkpoint_paths(
                 [str(checkpoints_link)], [str(unet_link)]
             )
 
@@ -50,21 +50,27 @@ class TestCheckpointPathOverlap:
         ]
         assert len(warning_messages) == 1
         assert "checkpoints" in warning_messages[0].lower()
-        assert "diffusion_models" in warning_messages[0].lower() or "unet" in warning_messages[0].lower()
+        assert (
+            "diffusion_models" in warning_messages[0].lower()
+            or "unet" in warning_messages[0].lower()
+        )
         # Verify warning mentions backward compatibility fallback
-        assert "falling back" in warning_messages[0].lower() or "backward compatibility" in warning_messages[0].lower()
+        assert (
+            "falling back" in warning_messages[0].lower()
+            or "backward compatibility" in warning_messages[0].lower()
+        )
 
         # Verify only one path is returned (deduplication still works)
-        assert len(result) == 1
+        assert len(all_paths) == 1
         # Prioritizes checkpoints path for backward compatibility
-        assert _normalize(result[0]) == _normalize(str(checkpoints_link))
+        assert _normalize(all_paths[0]) == _normalize(str(checkpoints_link))
 
-        # Verify checkpoints_roots has the path (prioritized)
-        assert len(config.checkpoints_roots) == 1
-        assert _normalize(config.checkpoints_roots[0]) == _normalize(str(checkpoints_link))
+        # Verify checkpoint_roots has the path (prioritized)
+        assert len(checkpoint_roots) == 1
+        assert _normalize(checkpoint_roots[0]) == _normalize(str(checkpoints_link))
 
         # Verify unet_roots is empty (overlapping paths removed)
-        assert config.unet_roots == []
+        assert unet_roots == []
 
     def test_non_overlapping_paths_no_warning(
         self, monkeypatch: pytest.MonkeyPatch, tmp_path, caplog
@@ -83,7 +89,7 @@ class TestCheckpointPathOverlap:
             config._preview_root_paths = set()
             config._cached_fingerprint = None
 
-            result = config._prepare_checkpoint_paths(
+            all_paths, checkpoint_roots, unet_roots = config._prepare_checkpoint_paths(
                 [str(checkpoints_dir)], [str(unet_dir)]
             )
 
@@ -97,14 +103,14 @@ class TestCheckpointPathOverlap:
         assert len(warning_messages) == 0
 
         # Verify both paths are returned
-        assert len(result) == 2
-        normalized_result = [_normalize(p) for p in result]
+        assert len(all_paths) == 2
+        normalized_result = [_normalize(p) for p in all_paths]
         assert _normalize(str(checkpoints_dir)) in normalized_result
         assert _normalize(str(unet_dir)) in normalized_result
 
         # Verify both roots are properly set
-        assert len(config.checkpoints_roots) == 1
-        assert len(config.unet_roots) == 1
+        assert len(checkpoint_roots) == 1
+        assert len(unet_roots) == 1
 
     def test_partial_overlap_prioritizes_checkpoints(
         self, monkeypatch: pytest.MonkeyPatch, tmp_path, caplog
@@ -129,9 +135,9 @@ class TestCheckpointPathOverlap:
             config._cached_fingerprint = None
 
             # One checkpoint path overlaps with one unet path
-            result = config._prepare_checkpoint_paths(
+            all_paths, checkpoint_roots, unet_roots = config._prepare_checkpoint_paths(
                 [str(shared_link), str(separate_checkpoint)],
-                [str(shared_link), str(separate_unet)]
+                [str(shared_link), str(separate_unet)],
             )
 
         # Verify warning was logged for the overlapping path
@@ -144,17 +150,20 @@ class TestCheckpointPathOverlap:
         assert len(warning_messages) == 1
 
         # Verify 3 unique paths (shared counted once as checkpoint, plus separate ones)
-        assert len(result) == 3
+        assert len(all_paths) == 3
 
         # Verify the overlapping path appears in warning message
-        assert str(shared_link.name) in warning_messages[0] or str(shared_dir.name) in warning_messages[0]
+        assert (
+            str(shared_link.name) in warning_messages[0]
+            or str(shared_dir.name) in warning_messages[0]
+        )
 
-        # Verify checkpoints_roots includes both checkpoint paths (including the shared one)
-        assert len(config.checkpoints_roots) == 2
-        checkpoint_normalized = [_normalize(p) for p in config.checkpoints_roots]
+        # Verify checkpoint_roots includes both checkpoint paths (including the shared one)
+        assert len(checkpoint_roots) == 2
+        checkpoint_normalized = [_normalize(p) for p in checkpoint_roots]
         assert _normalize(str(shared_link)) in checkpoint_normalized
         assert _normalize(str(separate_checkpoint)) in checkpoint_normalized
 
         # Verify unet_roots only includes the non-overlapping unet path
-        assert len(config.unet_roots) == 1
-        assert _normalize(config.unet_roots[0]) == _normalize(str(separate_unet))
+        assert len(unet_roots) == 1
+        assert _normalize(unet_roots[0]) == _normalize(str(separate_unet))

tests/test_checkpoint_loaders.py

@@ -0,0 +1,158 @@
+"""Tests for checkpoint and unet loaders with extra folder paths support"""
+
+import pytest
+import os
+
+
+# Get project root directory (ComfyUI-Lora-Manager folder)
+PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+class TestCheckpointLoaderLM:
+    """Test CheckpointLoaderLM node"""
+
+    def test_class_attributes(self):
+        """Test that CheckpointLoaderLM has required class attributes"""
+        # Import in a way that doesn't require ComfyUI
+        import ast
+
+        filepath = os.path.join(PROJECT_ROOT, "py", "nodes", "checkpoint_loader.py")
+
+        with open(filepath, "r") as f:
+            tree = ast.parse(f.read())
+
+        # Find CheckpointLoaderLM class
+        classes = {
+            node.name: node for node in ast.walk(tree) if isinstance(node, ast.ClassDef)
+        }
+        assert "CheckpointLoaderLM" in classes
+
+        cls = classes["CheckpointLoaderLM"]
+
+        # Check for NAME attribute
+        name_attr = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.Assign)
+            and any(t.id == "NAME" for t in n.targets if isinstance(t, ast.Name))
+        ]
+        assert len(name_attr) > 0, "CheckpointLoaderLM should have NAME attribute"
+
+        # Check for CATEGORY attribute
+        cat_attr = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.Assign)
+            and any(t.id == "CATEGORY" for t in n.targets if isinstance(t, ast.Name))
+        ]
+        assert len(cat_attr) > 0, "CheckpointLoaderLM should have CATEGORY attribute"
+
+        # Check for INPUT_TYPES method
+        input_types = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.FunctionDef) and n.name == "INPUT_TYPES"
+        ]
+        assert len(input_types) > 0, "CheckpointLoaderLM should have INPUT_TYPES method"
+
+        # Check for load_checkpoint method
+        load_method = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.FunctionDef) and n.name == "load_checkpoint"
+        ]
+        assert len(load_method) > 0, (
+            "CheckpointLoaderLM should have load_checkpoint method"
+        )
+
+
+class TestUNETLoaderLM:
+    """Test UNETLoaderLM node"""
+
+    def test_class_attributes(self):
+        """Test that UNETLoaderLM has required class attributes"""
+        # Import in a way that doesn't require ComfyUI
+        import ast
+
+        filepath = os.path.join(PROJECT_ROOT, "py", "nodes", "unet_loader.py")
+
+        with open(filepath, "r") as f:
+            tree = ast.parse(f.read())
+
+        # Find UNETLoaderLM class
+        classes = {
+            node.name: node for node in ast.walk(tree) if isinstance(node, ast.ClassDef)
+        }
+        assert "UNETLoaderLM" in classes
+
+        cls = classes["UNETLoaderLM"]
+
+        # Check for NAME attribute
+        name_attr = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.Assign)
+            and any(t.id == "NAME" for t in n.targets if isinstance(t, ast.Name))
+        ]
+        assert len(name_attr) > 0, "UNETLoaderLM should have NAME attribute"
+
+        # Check for CATEGORY attribute
+        cat_attr = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.Assign)
+            and any(t.id == "CATEGORY" for t in n.targets if isinstance(t, ast.Name))
+        ]
+        assert len(cat_attr) > 0, "UNETLoaderLM should have CATEGORY attribute"
+
+        # Check for INPUT_TYPES method
+        input_types = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.FunctionDef) and n.name == "INPUT_TYPES"
+        ]
+        assert len(input_types) > 0, "UNETLoaderLM should have INPUT_TYPES method"
+
+        # Check for load_unet method
+        load_method = [
+            n
+            for n in cls.body
+            if isinstance(n, ast.FunctionDef) and n.name == "load_unet"
+        ]
+        assert len(load_method) > 0, "UNETLoaderLM should have load_unet method"
+
+
+class TestUtils:
+    """Test utility functions"""
+
+    def test_get_checkpoint_info_absolute_exists(self):
+        """Test that get_checkpoint_info_absolute function exists in utils"""
+        import ast
+
+        filepath = os.path.join(PROJECT_ROOT, "py", "utils", "utils.py")
+
+        with open(filepath, "r") as f:
+            tree = ast.parse(f.read())
+
+        functions = [
+            node.name for node in ast.walk(tree) if isinstance(node, ast.FunctionDef)
+        ]
+        assert "get_checkpoint_info_absolute" in functions, (
+            "get_checkpoint_info_absolute should exist"
+        )
+
+    def test_format_model_name_for_comfyui_exists(self):
+        """Test that _format_model_name_for_comfyui function exists in utils"""
+        import ast
+
+        filepath = os.path.join(PROJECT_ROOT, "py", "utils", "utils.py")
+
+        with open(filepath, "r") as f:
+            tree = ast.parse(f.read())
+
+        functions = [
+            node.name for node in ast.walk(tree) if isinstance(node, ast.FunctionDef)
+        ]
+        assert "_format_model_name_for_comfyui" in functions, (
+            "_format_model_name_for_comfyui should exist"
+        )