Handle save paths across Windows drives

dumas_image_nodes.py

@@ -95,6 +95,13 @@ def _safe_pattern(value):
     return value
 
 
+def _is_within_directory(parent_path, child_path):
+    try:
+        return os.path.commonpath([parent_path, child_path]) == parent_path
+    except ValueError:
+        return False
+
+
 def _next_counter(directory, filename_template):
     os.makedirs(directory, exist_ok=True)
     if "%counter%" not in filename_template:
@@ -356,7 +363,7 @@ class DumasSaveImageNode:
                     pnginfo = _build_pnginfo(prompt=prompt, extra_pnginfo=extra_pnginfo)
                 image.save(full_path, "PNG", pnginfo=pnginfo)
 
-            if os.path.commonpath([output_dir, full_path]) == output_dir:
+            if _is_within_directory(output_dir, full_path):
                 subfolder = os.path.relpath(frame_dir, output_dir)
                 ui_images.append(
                     {

tests/test_dumas_image_nodes.py

@@ -4,6 +4,7 @@ import sys
 import tempfile
 import types
 import unittest
+from unittest import mock
 
 
 class FakeImageArray:
@@ -185,6 +186,32 @@ class DumasImageNodeTests(unittest.TestCase):
         self.assertEqual(result["ui"]["images"][0]["type"], "external")
         self.assertEqual(result["ui"]["images"][0]["subfolder"], external_dir.replace("\\", "/"))
 
+    def test_save_image_handles_windows_different_drive_paths(self):
+        node = self.image_nodes.DumasSaveImageNode()
+        image = FakeTensorBatch()
+
+        with mock.patch.object(
+            self.image_nodes.folder_paths,
+            "get_output_directory",
+            return_value="C:\\ComfyUI\\output",
+        ), mock.patch.object(
+            self.image_nodes.os.path,
+            "abspath",
+            return_value="D:\\renders",
+        ):
+            result = node.save_images(
+                images=image,
+                folder="D:\\renders",
+                pattern="drive_%counter%",
+                format="png",
+                quality=100,
+                embed_workflow=False,
+                save_on_run=True,
+            )
+
+        self.assertEqual(result["ui"]["images"][0]["type"], "external")
+        self.assertEqual(result["ui"]["images"][0]["subfolder"], "D:/renders")
+
     def test_save_image_skips_when_save_is_disabled(self):
         node = self.image_nodes.DumasSaveImageNode()
         image = FakeTensorBatch()