fix: Make ColorTransfer node ref_image mandatory (CORE-140)

[alexisrolland]

The ColorTransfer node has a ref_image input which is optional but when it is not provided, the node triggers the error:

TypeError: ColorTransfer.execute() missing 1 required positional argument: 'image_ref'

• This PR changes the ref_image input to be optional
• Add a user friendly display name

Before:

After:

[coderabbitai]

📝 Walkthrough

Walkthrough

The ColorTransfer node schema in comfy_extras/nodes_post_processing.py was modified: the image_ref input is no longer optional and its tooltip was shortened to "Reference image(s) to match colors to." The order and definitions of the other inputs (image_target, method, source_stats, strength) were left unchanged.

🚥 Pre-merge checks | ✅ 2 | ❌ 3

❌ Failed checks (3 warnings)

Check name	Status	Explanation	Resolution
Title check	⚠️ Warning	The title states the PR fixes a ColorTransfer error when ref_image is none, but the changes actually make ref_image mandatory, not optional.	Update the title to accurately reflect that the change makes image_ref mandatory rather than optional, such as 'fix: Make ColorTransfer image_ref input mandatory to prevent missing argument error'.
Description check	⚠️ Warning	The description describes the intent to make ref_image optional and fix the error, but the actual changes in the PR make ref_image mandatory by removing optional=True.	Clarify the description to accurately explain that the fix makes image_ref a required input rather than optional, preventing the error when the argument is missing from the function call.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

comfy_extras/nodes_post_processing.py (1)

841-842: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

image_ref is None is now unreachable dead code.

Since this PR removes optional=True from the image_ref input, the execution framework will always provide a tensor here. The image_ref is None branch can never be taken and should be cleaned up.

🧹 Proposed cleanup

-        if strength == 0 or image_ref is None:
+        if strength == 0:
             return io.NodeOutput(image_target)

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@comfy_extras/nodes_post_processing.py` around lines 841 - 842, The condition
"image_ref is None" in the post-processing early-return is dead code now that
image_ref is always provided; in the function containing the line "if strength
== 0 or image_ref is None: return io.NodeOutput(image_target)" remove the "or
image_ref is None" check so the branch only checks strength (i.e., change to "if
strength == 0: return io.NodeOutput(image_target)"), and run/adjust any related
tests or callers expecting a possible None value for image_ref; keep references
to io.NodeOutput and image_target unchanged.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Outside diff comments:
In `@comfy_extras/nodes_post_processing.py`:
- Around line 841-842: The condition "image_ref is None" in the post-processing
early-return is dead code now that image_ref is always provided; in the function
containing the line "if strength == 0 or image_ref is None: return
io.NodeOutput(image_target)" remove the "or image_ref is None" check so the
branch only checks strength (i.e., change to "if strength == 0: return
io.NodeOutput(image_target)"), and run/adjust any related tests or callers
expecting a possible None value for image_ref; keep references to io.NodeOutput
and image_target unchanged.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 31c5ea93-4eb8-4508-8020-612652e9b86c

📥 Commits

Reviewing files that changed from the base of the PR and between 3a42c40 and 29d5f61.

📒 Files selected for processing (1)

• comfy_extras/nodes_post_processing.py

[alexisrolland]

After discussing with @rattus128 we aligned that it would be preferable to make ref_image mandatory rather than having a no-op node behavior. Since the original node was broken anyway this shouldn't affect existing workflows.