[rush] rushd: cancelling rushx-client (Ctrl+C/SIGTERM) SIGKILLs the script without a graceful signal and exits 1 with "An unknown error occurred."

The issue is in libraries/rush-daemon/src/GlobalCommandExecutionContext.ts, specifically the terminateChild method. Start by examining how requestCancel is handled and how signals are forwarded. Look at SubprocessTerminator.killProcessTree and the mapping in CommandResultPolicy.ts. The fix involves adding a graceful signal phase before SIGKILL, modifying the requestCancel payload to carry the signal, and adjusting exit codes. Test with a script that traps signals to verify graceful termination.

Summary

rushx-client forwards SIGINT/SIGTERM as requestCancel. The daemon then aborts the GlobalCommandExecutionContext, whose terminateChild immediately calls SubprocessTerminator.killProcessTree, which is process.kill(-pid, 'SIGKILL'). The script never receives SIGINT or SIGTERM. Dev servers leave lock/pid files and ports behind, and test runners skip teardown. RushXCommand then reports the killed shell as Error: An unknown error occurred., and the client exits 1 instead of 130/143.

Repro steps

Take a rushx script that traps SIGINT/SIGTERM/SIGHUP, writes a marker file, and exits 40.

To its credit, the daemon kills the whole tree, so no orphans are left behind.

Expected result: Emulate a terminal Ctrl+C. Send the same signal (SIGINT/SIGTERM) to the script's process group, wait a bounded grace period (for example 2-5 s, within the client's cancellation timeout), then SIGKILL. The client exits 128 + signo and does not print a bogus "unknown error".

Actual result: The script is killed immediately with SIGKILL, the client exits 1, and the message is misleading.

Details

Root cause (main @ 60007c9a8c): libraries/rush-daemon/src/GlobalCommandExecutionContext.ts:343-355 (terminateChild) calls killProcessTree (SIGKILL) directly. CommandResultPolicy.ts:65-68 maps the result to exit code 1.

Suggested fix: add a graceful phase: process.kill(-child.pid, requestSignal ?? 'SIGINT'), then killProcessTree after a grace timeout. Carry the client's signal in requestCancel (for example an additive optional signal field). Suppress the "unknown error" message for aborted requests, and return 130/143 (related: #6060, for phased builds).

This was found during an automated performance/behavior analysis of rush-client/rushd on Linux and independently reproduced.

Standard questions