Error when adding things to the body sections

[Starkomi]

I was about to add custom nail polish for Emre, i got error.

[Mustard2]

Hi! What were you trying to add? A color, a bool value, or...?

[Mustard2]

@claude How to solve this? Should we add a clearer error checking this possibility and reporting a generic error?
Don't create a new branch, just advice.

[claude]

Claude finished @Mustard2's task in 48s —— View job

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Root cause found

• Gather context (read traceback image, locate custom_properties/ops_add.py)
• Analyze root cause
• Post advice

The traceback from the screenshot:

File ".../MustardUI/custom_properties/ops_add.py", line 82, in execute
    rna, path = clipboard.rsplit(".", 1)
ValueError: not enough values to unpack (expected 2, got 1)

This is in MustardUI_Property_MenuAdd.execute() (custom_properties/ops_add.py:72-90), the operator behind "Add to MustardUI" in the right-click context menu.

What's happening:

try:
    bpy.ops.ui.copy_data_path_button(full_path=True)
except Exception:
    self.report({"ERROR"}, "MustardUI - Invalid selection.")
    return {"FINISHED"}

clipboard = context.window_manager.clipboard
blender_custom_property = "][" in clipboard
if not blender_custom_property:
    rna, path = clipboard.rsplit(".", 1)   # <-- line 82, crashes here

bpy.ops.ui.copy_data_path_button() doesn't always raise an exception when it can't produce a path — for some properties (values driven by unlinked/invalid contexts, certain node-group sockets, some add-on-preference-backed properties, etc.) it silently returns {'CANCELLED'} and leaves context.window_manager.clipboard untouched (or empty). In that case the code falls through the try/except unharmed, then blindly does clipboard.rsplit(".", 1) on a string that has no . in it (e.g. an empty string, or leftover clipboard content from something the user copied earlier), which raises the unhandled ValueError shown in the screenshot — since it's a property on a "Nail (Hands) Metallic" slider, it's likely a node input/value that copy_data_path_button couldn't resolve to a real data path.

Suggested fix: don't rely solely on the try/except around the operator call — also check its return value, and guard the rsplit itself so an un-copyable property produces a clean, reportable error instead of an unhandled Python traceback:

result = bpy.ops.ui.copy_data_path_button(full_path=True)
if "CANCELLED" in result:
    self.report({"ERROR"}, "MustardUI - This property does not support being added "
                            "to MustardUI (no valid data path could be found).")
    return {"FINISHED"}

clipboard = context.window_manager.clipboard
blender_custom_property = "][" in clipboard
if not blender_custom_property:
    if "." not in clipboard:
        self.report({"ERROR"}, "MustardUI - This property does not support being added "
                                "to MustardUI (no valid data path could be found).")
        return {"FINISHED"}
    rna, path = clipboard.rsplit(".", 1)

That turns the crash into the same kind of generic, user-facing self.report({"ERROR"}, ...) message already used a few lines above for the "Invalid selection" case, so the user gets clear feedback ("this property can't be added") instead of a Python traceback, and it's consistent with the existing error-handling style in this operator.

It would also help to ask the reporter exactly which property/slider they right-clicked (metallic value on a linked/node-group input? a custom property?) to confirm the exact case, but the fix above should safely handle it regardless of the specific cause.

[Mustard2]

@Starkomi I added an error message for a generic failure you are seeing. If you can, let me know what you were trying to add (a screenshot of where you were right-cliking -> adding the custom property), so I can fix the specific case.

[Starkomi]

a nail polish customization feature