Fix serialization of functions from import_js_module

[hoodmane]

This change was originally part of #6173 but it got reverted. This caused cloudflare/workers-sdk#12961

[ask-bonk]

UnknownError: ProviderInitError

github run

[ask-bonk]

@hoodmane Bonk workflow failed. Check the logs for details.

View workflow run · To retry, trigger Bonk again.

[ask-bonk]

The change is a one-line fix. The old code at line 70 was:

if (!mod || typeof mod !== 'object') {

The new code is:

if (!mod || !['object', 'function'].includes(typeof mod)) {

This allows createImportProxy to also wrap function values in a Proxy, not just object values. This is consistent with line 96 inside the get trap which already uses the same ['object', 'function'].includes(typeof orig) pattern.

The logic is correct: Proxy targets in JavaScript can be either objects or functions. The old code was returning functions un-proxied, which means functions from import_js_module would fail serialization since they wouldn't get the importName/getAccessorList symbol handlers. This matches the linked issue about function serialization.

The fix is minimal, targeted, and consistent with the existing pattern on line 96. No backward compatibility concerns since this only affects the IS_CREATING_SNAPSHOT path. No security implications.

LGTM

github run

[codspeed-hq]

Merging this PR will improve performance by 38.42%

⚡ 1 improved benchmark
✅ 71 untouched benchmarks
⏩ 129 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	simpleStringBody[Response]	26.7 µs	19.3 µs	+38.42%

---

_{Comparing hoodmane/fix-function-serialization (5eb82f3) with main (d9d8fa6)}

Footnotes

1. 129 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.56%. Comparing base (7a7288e) to head (5eb82f3).
⚠️ Report is 441 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6632      +/-   ##
==========================================
- Coverage   70.68%   66.56%   -4.12%     
==========================================
  Files         420      405      -15     
  Lines      113010   117533    +4523     
  Branches    18531    19382     +851     
==========================================
- Hits        79881    78240    -1641     
- Misses      22086    27721    +5635     
- Partials    11043    11572     +529     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[ryanking13]

Ahh, thanks. This was part of my reverted PR (#6173), but I forgot to reland before changing workers-py... Thakns a lot