## Summary
Fixes compatibility issue with Node.js libraries that use
`Object.assign(promise, childProcess)` pattern, specifically `tinyspawn`
(used by `youtube-dl-exec`).
## Problem
In Node.js, child process stdio properties (`stdin`, `stdout`, `stderr`,
`stdio`) are enumerable own properties that can be copied by
`Object.assign()`. In Bun, they were non-enumerable getters on the
prototype, causing `Object.assign()` to fail copying them.
This broke libraries like:
- `tinyspawn` - uses `Object.assign(promise, childProcess)` to merge
properties
- `youtube-dl-exec` - depends on tinyspawn internally
## Solution
Make stdio properties enumerable own properties during spawn while
preserving:
- ✅ Lazy initialization (streams created only when accessed)
- ✅ Original getter functionality and caching
- ✅ Performance (minimal overhead)
## Testing
- Added comprehensive regression tests
- Verified compatibility with `tinyspawn` and `youtube-dl-exec`
- Existing child_process tests still pass
## Related
- Fixes: https://github.com/microlinkhq/youtube-dl-exec/issues/246🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
