fix(tools): kill process group when bash task aborts

[yan-ad]

Summary

• add an RAII guard for foreground bash process groups
• kill all descendants when a tool future is aborted or dropped
• add a regression test covering a long-running Node descendant

Root cause

Command::kill_on_drop only terminates the spawned shell. When the tool future was aborted, Node descendants could survive with an active event loop and continue consuming memory.

Validation

• cargo fmt --all
• cargo test tools::bash::tests
• cargo check
• git diff --check

[Blankeos]

PR Review

fix/kill-node-descendants-on-tool-abort → main

PR: #41

Merge confidence: 4.5/5

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Suggested GitHub PR body

Foreground bash already killpgs when the shell exits, but Command::kill_on_drop only SIGKILLs the spawned shell. User-cancel drops the tool future (select! on cancel_token in aisdk/response.rs, or StreamTextResponse aborting its join handle) without running terminate_child, so Node/setInterval descendants in the same process group survived and kept an event loop.

RAII ProcessGroupGuard killpg(SIGKILL)s on Drop (and still take()s the pid on the happy-path shell-exit kill). Regression test aborts an in-flight node -e 'setInterval(...)' and asserts the descendant is gone.

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What changed

File	Role
src/tools/bash.rs	ProcessGroupGuard in execute_foreground only; Drop → kill_process_group; explicit .kill() still runs when the shell exits so pipes EOF; unix test aborted_tool_future_kills_node_descendants

1 commit: 311782f — fix(tools): kill process group when bash task aborts

+86 / −2. Background + interactive paths untouched.

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Checks run (read-only)

Check	Result
gh pr view 41	OPEN, MERGEABLE, CLEAN, not draft
origin/main ancestor of HEAD	yes (54afa0c)
git diff --check origin/main...HEAD	clean
cargo fmt --all -- --check	clean
cargo check --bin crabcode	ok
cargo test --bin crabcode tools::bash::tests	6/6 including new abort test (0.08s; node v24 present so it did not skip)
GitHub checks	plan pass; Release build jobs skipped (no test workflow on PRs)

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Regressions?

No functional regression on the covered path. Foreground success still kills the group when the shell exits (successful_command_kills_background_processes still passes). Abort/drop now matches that cleanup.

Intentional behavior: cancelling a foreground bash now SIGKILLs the whole process group, including & children (node, sleep, etc.). That is already true on successful shell exit; abort was the hole. Long-running servers belong in mode=background (ledger jobs) — unchanged.

Remaining risks (not blockers):

1. Test skips if node is missing (return; with no #[ignore]). Local run had node so it executed. CI here does not run this test job anyway.
2. Windows still a no-op (kill_process_group empty; no process_group). Pre-existing; test is #[cfg(unix)].
3. terminate_child does not take() the guard pid. Cancel-via-ctx.is_aborted() killpg's, then Drop killpg's again. Harmless unless the pgid is reused in that window (vanishingly unlikely).
4. No pid == 0 guard (jobs/spawn.rs has one). child.id() at spawn is never 0. Pre-existing.

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Migrations?

No. Prefs/history SQLite (src/persistence/migrations.rs) and auth.json / MCP creds are untouched.

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Merge checklist

• Open GitHub PR (#41)
• Scoped to foreground bash only (background/interactive not wrapped in the guard)
• cargo fmt --all -- --check
• cargo check
• cargo test tools::bash::tests — 6/6, new test actually ran (node present)
• git diff --check
• Optional: fail or sleep-fallback instead of silent skip when node is missing
• Optional: terminate_child should process_group_guard.kill() so Drop is a no-op
• Optional: pid == 0 early-return in kill_process_group (match jobs/spawn.rs)

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Confidence bumps

If you do this	New score
Don't silently skip the abort test (sleep+wait fallback, or #[ignore] + require-node in CI)	4.7/5
+ terminate_child disarms the guard via .kill() / .take()	4.9/5
+ pid == 0 guard in kill_process_group	5/5

The leak itself is covered: Drop of the foreground future now killpgs, which is exactly how production cancel drops tool_work.