## Summary
Fixes a panic that occurred when a WebSocket close frame's payload was
split across multiple TCP packets.
## The Bug
The panic occurred at `websocket_client.zig:681`:
```
panic: index out of bounds: index 24, len 14
```
This happened when:
- A close frame had a payload of 24 bytes (2 byte code + 22 byte reason)
- The first TCP packet contained 14 bytes (header + partial payload)
- The code tried to access `data[2..24]` causing the panic
## Root Causes
1. **Bounds checking issue**: The code assumed all close frame data
would arrive in one packet and tried to `@memcpy` without verifying
sufficient data was available.
2. **Premature flag setting**: `close_received = true` was set
immediately upon entering the close state. This prevented `handleData`
from being called again when the remaining bytes arrived (early return
at line 354).
## The Fix
Implemented proper fragmentation handling for close frames, following
the same pattern used for ping frames:
- Added `close_frame_buffering` flag to track buffering state
- Buffer incoming data incrementally using the existing
`ping_frame_bytes` buffer
- Track total expected length and bytes received so far
- Only set `close_received = true` after all bytes are received
- Wait for more data if the frame is incomplete
## Testing
- Created two regression tests that fragment close frames across
multiple packets
- All existing WebSocket tests pass (`test/js/web/websocket/`)
- Verified the original panic no longer occurs
## Related
This appears to be the root cause of crashes reported on Windows when
WebSocket connections close, particularly when close frames have reasons
that get fragmented by the network stack.
---
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
