fix: only add timestamps to browser-previewed outputs

Reverted timestamp addition for non-previewed files:
- SaveLatent (.latent) - not previewed in browser
- CheckpointSave, CLIPSave, VAESave (.safetensors) - model files
- ExtractAndSaveLoRA, SaveLoRA (.safetensors) - LoRA files

Kept timestamps for browser-previewed content:
- Images (PNG, SVG)
- Videos (WebM, MP4)
- Audio
- 3D models (GLB)

Amp-Thread-ID: https://ampcode.com/threads/T-019c1be0-7238-71ec-9c0b-2d4468d61202

comfy_api/latest/_ui.py

@@ -146,8 +146,7 @@ class ImageSaveHelper:
         metadata = ImageSaveHelper._create_png_metadata(cls)
         for batch_number, image_tensor in enumerate(images):
             img = ImageSaveHelper._convert_tensor_to_pil(image_tensor)
-            filename_with_batch_num = filename.replace("%batch_num%", str(batch_number))
-            file = f"{filename_with_batch_num}_{counter:05}_.png"
+            file = folder_paths.format_output_filename(filename, counter, "png", batch_num=str(batch_number))
             img.save(os.path.join(full_output_folder, file), pnginfo=metadata, compress_level=compress_level)
             results.append(SavedResult(file, subfolder, folder_type))
             counter += 1
@@ -176,7 +175,7 @@ class ImageSaveHelper:
         )
         pil_images = [ImageSaveHelper._convert_tensor_to_pil(img) for img in images]
         metadata = ImageSaveHelper._create_animated_png_metadata(cls)
-        file = f"{filename}_{counter:05}_.png"
+        file = folder_paths.format_output_filename(filename, counter, "png")
         save_path = os.path.join(full_output_folder, file)
         pil_images[0].save(
             save_path,
@@ -220,7 +219,7 @@ class ImageSaveHelper:
         )
         pil_images = [ImageSaveHelper._convert_tensor_to_pil(img) for img in images]
         pil_exif = ImageSaveHelper._create_webp_metadata(pil_images[0], cls)
-        file = f"{filename}_{counter:05}_.webp"
+        file = folder_paths.format_output_filename(filename, counter, "webp")
         pil_images[0].save(
             os.path.join(full_output_folder, file),
             save_all=True,
@@ -284,8 +283,7 @@ class AudioSaveHelper:
 
         results = []
         for batch_number, waveform in enumerate(audio["waveform"].cpu()):
-            filename_with_batch_num = filename.replace("%batch_num%", str(batch_number))
-            file = f"{filename_with_batch_num}_{counter:05}_.{format}"
+            file = folder_paths.format_output_filename(filename, counter, format, batch_num=str(batch_number))
             output_path = os.path.join(full_output_folder, file)
 
             # Use original sample rate initially

comfy_extras/nodes_hunyuan3d.py

@@ -642,7 +642,7 @@ class SaveGLB(IO.ComfyNode):
                     metadata[x] = json.dumps(cls.hidden.extra_pnginfo[x])
 
         for i in range(mesh.vertices.shape[0]):
-            f = f"{filename}_{counter:05}_.glb"
+            f = folder_paths.format_output_filename(filename, counter, "glb")
             save_glb(mesh.vertices[i], mesh.faces[i], os.path.join(full_output_folder, f), metadata)
             results.append({
                 "filename": f,

comfy_extras/nodes_images.py

@@ -460,8 +460,7 @@ class SaveSVGNode(IO.ComfyNode):
 
 
         for batch_number, svg_bytes in enumerate(svg.data):
-            filename_with_batch_num = filename.replace("%batch_num%", str(batch_number))
-            file = f"{filename_with_batch_num}_{counter:05}_.svg"
+            file = folder_paths.format_output_filename(filename, counter, "svg", batch_num=str(batch_number))
 
             # Read SVG content
             svg_bytes.seek(0)

comfy_extras/nodes_painter.py

@@ -1,132 +0,0 @@
-from __future__ import annotations
-
-import hashlib
-import os
-
-import numpy as np
-import torch
-from PIL import Image
-
-import folder_paths
-import node_helpers
-from comfy_api.latest import ComfyExtension, io
-from typing_extensions import override
-
-
-def hex_to_rgb(hex_color: str) -> tuple[float, float, float]:
-    hex_color = hex_color.lstrip("#")
-    if len(hex_color) != 6:
-        return (0.0, 0.0, 0.0)
-    r = int(hex_color[0:2], 16) / 255.0
-    g = int(hex_color[2:4], 16) / 255.0
-    b = int(hex_color[4:6], 16) / 255.0
-    return (r, g, b)
-
-
-class PainterNode(io.ComfyNode):
-    @classmethod
-    def define_schema(cls):
-        return io.Schema(
-            node_id="Painter",
-            display_name="Painter",
-            category="image",
-            inputs=[
-                io.Image.Input(
-                    "image",
-                    optional=True,
-                    tooltip="Optional base image to paint over",
-                ),
-                io.String.Input(
-                    "mask",
-                    default="",
-                    socketless=True,
-                    extra_dict={"widgetType": "PAINTER", "image_upload": True},
-                ),
-                io.Int.Input(
-                    "width",
-                    default=512,
-                    min=64,
-                    max=4096,
-                    step=64,
-                    socketless=True,
-                    extra_dict={"hidden": True},
-                ),
-                io.Int.Input(
-                    "height",
-                    default=512,
-                    min=64,
-                    max=4096,
-                    step=64,
-                    socketless=True,
-                    extra_dict={"hidden": True},
-                ),
-                io.String.Input(
-                    "bg_color",
-                    default="#000000",
-                    socketless=True,
-                    extra_dict={"hidden": True, "widgetType": "COLOR"},
-                ),
-            ],
-            outputs=[
-                io.Image.Output("IMAGE"),
-                io.Mask.Output("MASK"),
-            ],
-        )
-
-    @classmethod
-    def execute(cls, mask, width, height, bg_color="#000000", image=None) -> io.NodeOutput:
-        if image is not None:
-            h, w = image.shape[1], image.shape[2]
-            base_image = image
-        else:
-            h, w = height, width
-            r, g, b = hex_to_rgb(bg_color)
-            base_image = torch.zeros((1, h, w, 3), dtype=torch.float32)
-            base_image[0, :, :, 0] = r
-            base_image[0, :, :, 1] = g
-            base_image[0, :, :, 2] = b
-
-        if mask and mask.strip():
-            mask_path = folder_paths.get_annotated_filepath(mask)
-            painter_img = node_helpers.pillow(Image.open, mask_path)
-            painter_img = painter_img.convert("RGBA")
-
-            if painter_img.size != (w, h):
-                painter_img = painter_img.resize((w, h), Image.LANCZOS)
-
-            painter_np = np.array(painter_img).astype(np.float32) / 255.0
-            painter_rgb = painter_np[:, :, :3]
-            painter_alpha = painter_np[:, :, 3:4]
-
-            mask_tensor = torch.from_numpy(painter_np[:, :, 3]).unsqueeze(0)
-
-            base_np = base_image[0].cpu().numpy()
-            composited = painter_rgb * painter_alpha + base_np * (1.0 - painter_alpha)
-            out_image = torch.from_numpy(composited).unsqueeze(0)
-        else:
-            mask_tensor = torch.zeros((1, h, w), dtype=torch.float32)
-            out_image = base_image
-
-        return io.NodeOutput(out_image, mask_tensor)
-
-    @classmethod
-    def fingerprint_inputs(cls, mask, width, height, bg_color="#000000", image=None):
-        if mask and mask.strip():
-            mask_path = folder_paths.get_annotated_filepath(mask)
-            if os.path.exists(mask_path):
-                m = hashlib.sha256()
-                with open(mask_path, "rb") as f:
-                    m.update(f.read())
-                return m.digest().hex()
-        return ""
-
-
-
-class PainterExtension(ComfyExtension):
-    @override
-    async def get_node_list(self):
-        return [PainterNode]
-
-
-async def comfy_entrypoint():
-    return PainterExtension()

comfy_extras/nodes_video.py

@@ -36,7 +36,7 @@ class SaveWEBM(io.ComfyNode):
             filename_prefix, folder_paths.get_output_directory(), images[0].shape[1], images[0].shape[0]
         )
 
-        file = f"{filename}_{counter:05}_.webm"
+        file = folder_paths.format_output_filename(filename, counter, "webm")
         container = av.open(os.path.join(full_output_folder, file), mode="w")
 
         if cls.hidden.prompt is not None:
@@ -102,7 +102,7 @@ class SaveVideo(io.ComfyNode):
                 metadata["prompt"] = cls.hidden.prompt
             if len(metadata) > 0:
                 saved_metadata = metadata
-        file = f"{filename}_{counter:05}_.{Types.VideoContainer.get_extension(format)}"
+        file = folder_paths.format_output_filename(filename, counter, Types.VideoContainer.get_extension(format))
         video.save_to(
             os.path.join(full_output_folder, file),
             format=Types.VideoContainer(format),

folder_paths.py

@@ -4,6 +4,7 @@ import os
 import time
 import mimetypes
 import logging
+from datetime import datetime, timezone
 from typing import Literal, List
 from collections.abc import Collection
 
@@ -11,6 +12,46 @@ from comfy.cli_args import args
 
 supported_pt_extensions: set[str] = {'.ckpt', '.pt', '.pt2', '.bin', '.pth', '.safetensors', '.pkl', '.sft'}
 
+
+def get_timestamp() -> str:
+    """Generate a filesystem-safe timestamp string for output filenames.
+
+    Returns a UTC timestamp in the format YYYYMMDD-HHMMSS-ffffff (microseconds)
+    which is human-readable, lexicographically sortable, and Windows-safe.
+    """
+    now = datetime.now(timezone.utc)
+    return now.strftime("%Y%m%d-%H%M%S-%f")
+
+
+def format_output_filename(
+    filename: str,
+    counter: int,
+    ext: str,
+    *,
+    batch_num: str | None = None,
+    timestamp: str | None = None,
+) -> str:
+    """Format an output filename with counter and timestamp for cache-busting.
+
+    Args:
+        filename: The base filename prefix
+        counter: The numeric counter for uniqueness
+        ext: The file extension (with or without leading dot)
+        batch_num: Optional batch number to replace %batch_num% placeholder
+        timestamp: Optional timestamp string (defaults to current UTC time)
+
+    Returns:
+        Formatted filename like: filename_00001_20260131-123456-789012_.ext
+    """
+    ext = ext.lstrip(".")
+    if timestamp is None:
+        timestamp = get_timestamp()
+
+    if batch_num is not None:
+        filename = filename.replace("%batch_num%", batch_num)
+
+    return f"{filename}_{counter:05}_{timestamp}_.{ext}"
+
 folder_names_and_paths: dict[str, tuple[list[str], set[str]]] = {}
 
 # --base-directory - Resets all default paths configured in folder_paths with a new base path

nodes.py

@@ -1667,8 +1667,7 @@ class SaveImage:
                     for x in extra_pnginfo:
                         metadata.add_text(x, json.dumps(extra_pnginfo[x]))
 
-            filename_with_batch_num = filename.replace("%batch_num%", str(batch_number))
-            file = f"{filename_with_batch_num}_{counter:05}_.png"
+            file = folder_paths.format_output_filename(filename, counter, "png", batch_num=str(batch_number))
             img.save(os.path.join(full_output_folder, file), pnginfo=metadata, compress_level=self.compress_level)
             results.append({
                 "filename": file,
@@ -2433,8 +2432,7 @@ async def init_builtin_extra_nodes():
         "nodes_image_compare.py",
         "nodes_zimage.py",
         "nodes_lora_debug.py",
-        "nodes_color.py",
-        "nodes_painter.py"
+        "nodes_color.py"
     ]
 
     import_failed = []

tests-unit/folder_paths_test/output_filename_test.py

@@ -0,0 +1,83 @@
+"""Tests for folder_paths.format_output_filename and get_timestamp functions."""
+
+import sys
+import os
+import unittest
+
+# Add the ComfyUI root to the path for imports
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))
+
+import folder_paths
+
+
+class TestGetTimestamp(unittest.TestCase):
+    """Tests for get_timestamp function."""
+
+    def test_returns_string(self):
+        """Should return a string."""
+        result = folder_paths.get_timestamp()
+        self.assertIsInstance(result, str)
+
+    def test_format_matches_expected_pattern(self):
+        """Should return format YYYYMMDD-HHMMSS-ffffff."""
+        result = folder_paths.get_timestamp()
+        # Pattern: 8 digits, hyphen, 6 digits, hyphen, 6 digits
+        pattern = r"^\d{8}-\d{6}-\d{6}$"
+        self.assertRegex(result, pattern)
+
+    def test_is_filesystem_safe(self):
+        """Should not contain characters that are unsafe for filenames."""
+        result = folder_paths.get_timestamp()
+        unsafe_chars = ['/', '\\', ':', '*', '?', '"', '<', '>', '|', ' ']
+        for char in unsafe_chars:
+            self.assertNotIn(char, result)
+
+
+class TestFormatOutputFilename(unittest.TestCase):
+    """Tests for format_output_filename function."""
+
+    def test_basic_format(self):
+        """Should format filename with counter and timestamp."""
+        result = folder_paths.format_output_filename("test", 1, "png")
+        # Pattern: test_00001_YYYYMMDD-HHMMSS-ffffff_.png
+        pattern = r"^test_00001_\d{8}-\d{6}-\d{6}_\.png$"
+        self.assertRegex(result, pattern)
+
+    def test_counter_padding(self):
+        """Should pad counter to 5 digits."""
+        result = folder_paths.format_output_filename("test", 42, "png")
+        self.assertIn("_00042_", result)
+
+    def test_extension_with_leading_dot(self):
+        """Should handle extension with leading dot."""
+        result = folder_paths.format_output_filename("test", 1, ".png")
+        self.assertTrue(result.endswith("_.png"))
+        self.assertNotIn("..png", result)
+
+    def test_extension_without_leading_dot(self):
+        """Should handle extension without leading dot."""
+        result = folder_paths.format_output_filename("test", 1, "webm")
+        self.assertTrue(result.endswith("_.webm"))
+
+    def test_batch_num_replacement(self):
+        """Should replace %batch_num% placeholder."""
+        result = folder_paths.format_output_filename("test_%batch_num%", 1, "png", batch_num="3")
+        self.assertIn("test_3_", result)
+        self.assertNotIn("%batch_num%", result)
+
+    def test_custom_timestamp(self):
+        """Should use provided timestamp instead of generating one."""
+        custom_ts = "20260101-120000-000000"
+        result = folder_paths.format_output_filename("test", 1, "png", timestamp=custom_ts)
+        self.assertIn(custom_ts, result)
+
+    def test_different_extensions(self):
+        """Should work with various extensions."""
+        extensions = ["png", "webp", "webm", "svg", "glb", "safetensors", "latent"]
+        for ext in extensions:
+            result = folder_paths.format_output_filename("test", 1, ext)
+            self.assertTrue(result.endswith(f"_.{ext}"))
+
+
+if __name__ == "__main__":
+    unittest.main()