fix(combobox): resolve reactive item labels instead of stringifying them

[harshasiddartha]

What is it?

• Feature / enhancement
• Bug
• Docs / tests
• Other

Why is it needed?

Fixes #1184

Selecting an item in the headless Combobox writes [object Object] into the input whenever the item label is a reactive expression.

Root cause

combobox-inline-comp.tsx builds the items map at pre-render time and casts the label's children straight to a string:

const displayValue = labelProps.children as string;

That holds for a literal (<Combobox.ItemLabel>Apple</Combobox.ItemLabel>), but when the label comes from a reactive expression - e.g. {user.label} where user comes from a useStore - the optimizer turns those children into a derived signal. The cast lies, and the signal object is what gets written to inputRef.value.value in selectionManager$. I confirmed this by decoding the Qwik state of a rendered page: the map entries serialize with Qwik's derived-signal marker (�n! label) rather than as strings.

The same bad value also flows into the default filter (displayValue.toLowerCase() in combobox-item.tsx), so filtering silently breaks for those items too.

Fix

Unwrap the children before storing the display value: resolve signals (recursively), join arrays of children, and stringify the rest. String labels take exactly the same path as before, so this is backwards compatible.

Verification

Added a store example (items whose labels come from a store) and a regression test in combobox.test.ts. It fails on main and passes with the fix:

  ✓  1 [logic] › combobox.test.ts:683:5 › Props › option value › GIVEN a combobox whose item labels come from a store
        WHEN an option is selected
        THEN the input displays the item label instead of "[object Object]" (758ms)

  1 passed (2.7s)

Full combobox suite (--retries=2 --workers=1): 69 passed, 2 flaky, 1 failed. The one failure - combobox.test.ts:253 (the latest selected option should be highlighted when the menu is opened again) - also fails on unmodified main on my machine, so it is pre-existing and unrelated to this change. nx lint headless and nx build headless both pass.

Note: select-inline.tsx has the same child.props.children as string cast and is likely affected by the same problem, but I left it out to keep this PR scoped to the reported issue. Happy to follow up.

Checklist:

• My code follows the developer guidelines of this project
• I have performed a self-review of my own code
• I have ran pnpm change and documented my changes
• I have add necessary docs (if needed)
• Added new tests to cover the fix / functionality

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[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[harshasiddartha]

I have read the CLA Document and I hereby sign the CLA

[Sebosek]

Hi, how long does it usually take to have the fix released?