Bash tool: timeout-killed processes not detected as completed; user must manually abort

[void0x14]

Bug

Opencode bash tool does not detect process completion when the command spawns long-lived child processes that outlive the parent.

Observed Behavior

Running timeout 60 sudo ./zig-out/bin/siege_engine enp37s0 via Opencode bash tool — siege_engine is killed by timeout after 60s (exit 124) but Opencode never returns control. The tool stays in "running" state until user presses ESC, which logs error=Aborted process.

Session log (2026-05-21T130902.log):

13:10:07  pattern=timeout 60 sudo ... siege_engine enp37s0
13:11:06  type=message.part.updated publishing
[GAP — 6+ minutes, no completion detected]
13:17:27  session.prompt cancel
13:17:27  error=Aborted process

Child processes that outlive siege_engine:

• Chrome: 18 processes (browser, crashpad, zygote, GPU, network, storage, renderer, audio)
• nanodet_live: 2 instances (vision inference sidecar)
• 1 zombie cat process

Output: 148KB (2005 lines), truncated at 51200 bytes / 2000 lines. Full output saved to tool-output file.

Expected

Bash tool should detect when the wrapped command exits and return control, regardless of orphan child processes or output volume.

Environment

• Opencode: 1.15.6
• OS: CachyOS
• Bash tool uses: /usr/bin/zsh -c

Evidence

All files: https://gist.github.com/void0x14/2ceb0c93452abbfbb44d167b7cefb12c

• evidence-summary.txt — Timeline
• log-excerpt.txt — Log lines
• process-tree.txt — pstree (opencode + orphans)
• tool_e4ab26763001RP9MpQfR3ULKP8 — Truncated output (148KB)
• screenshot-*.jpg.b64 — Visual evidence (base64 -d file.b64 > file.jpg)

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• bash tool hangs when command spawns background child processes #20902: bash tool hangs when command spawns background child processes (same root cause: child processes keeping stdio pipes open, preventing process completion detection)
• [Bug]: Bash tool hangs on fast-exiting processes and locks database on massive output #21000: Bash tool hangs on fast-exiting processes and locks database on massive output (similar issue with process state not resolving correctly)

Your issue adds useful detail around the timeout wrapper and large output volume, which may be worth referencing in those issues as additional reproduction cases.