Summary

Fixes critical memory leaks and zombie process accumulation that cause kernel panics on macOS. Users with 16GB MacBook Pros report 10+ zombie opencode processes consuming ~9.4GB, requiring forced reboots every few days.

Closes #12687

Root Causes Addressed

1. No signal handlers — index.ts and worker.ts had no SIGTERM/SIGINT/SIGHUP handlers. When a terminal is closed (SIGHUP), all child processes (LSP servers, MCP servers, bash tool processes spawned with detached: true) are orphaned as zombies. This is the primary cause.

2. Unreachable cleanup code in serve.ts — await new Promise(() => {}) blocks forever, making server.stop() dead code.

3. O(n²) string concatenation in bash tool and prompt shell — output += chunk.toString() causes massive transient memory spikes for verbose commands, plus Buffer.concat(chunks).toString() was being called on every data event for TUI metadata preview.

4. Deep clone of entire message history — clone(msgs) from remeda deep-copies all messages (including large tool outputs) every prompt loop iteration just to wrap text in <system-reminder> tags.

5. Missing dispose callbacks — PermissionNext and Question modules register state without dispose callbacks. Pending promise closures (holding references to resolve/reject functions and their associated data) leak on instance disposal.

6. Unbounded FileTime data — FileTime read records and locks grow without bound and have no cleanup on instance disposal.

Changes (8 files)

Fix 1: Graceful shutdown signal handlers (index.ts, worker.ts, serve.ts)

• Added SIGTERM/SIGINT/SIGHUP handlers that call Instance.disposeAll() before exit
• Added Instance.disposeAll() to the finally block in index.ts
• Replaced unreachable await new Promise(() => {}) in serve.ts with signal-based exit + Instance.disposeAll() + server.stop()

Fix 2: Bash/shell output ring buffer (bash.ts, prompt.ts)

• Replaced output += chunk.toString() with Buffer[] array accumulation
• Capped at 10MB — oldest chunks are evicted when limit is exceeded
• Added a separate preview string (capped at 30KB) for TUI metadata display, avoiding Buffer.concat() on every data event
• Final output joined with Buffer.concat(chunks).toString() only at end

Fix 3: Shallow copy instead of deep clone (prompt.ts)

• Replaced clone(msgs) with msgs.map(msg => ({ ...msg, parts: msg.parts.map(part => ({ ...part })) }))
• Removed unused import { clone } from "remeda"

Fix 4: Missing dispose callbacks (permission/next.ts, question/index.ts)

• Added dispose callbacks that reject all pending promises with RejectedError
• Matches the pattern already used in the legacy Permission module

Fix 5: FileTime cleanup (file/time.ts)

• Added dispose callback to FileTime.state that clears read records and locks map

Testing

• tsgo --noEmit passes across all 17 packages (pre-push hook verified)
• bun test runs 844 tests across 59 files with 0 failures
• All changes follow existing patterns (e.g., Instance.state(init, dispose?) lifecycle, RejectedError for pending promise rejection)

Related Issues/PRs

Multiple community PRs address overlapping subsets of this problem: #12053, #10392, #12259, #9693, #9146, #9147, #7914. This PR provides a comprehensive fix covering all identified root causes.