tsc is not resposive to `ctrl-c`

[lukesandberg]

When you run tsc and attempt to interrupt a build it does not respond instead it just complets the build

This is because typescript-go installs signal handlers to propagate sigterm and sigint to the context.Context object

However this is not always threaded all the way through the build

I prepared microsoft/typescript-go#4592 to fix this, but the fix is non-trivial

Alternatively should we just not install signal handlers and let normal behavior proceed?

[anthonyshew]

Additional context: I ran into this separately from Luke (though also in a Vercel repo, as fate would have it!) and found these behaviors.

Hangs when I do one ^C:

▲ 👟  pnpm run dev:ts

> app@0.0.12 dev:ts /my/repo/path
> tsc -b -w --preserveWatchOutput

[10:19:06 AM] Starting compilation in watch mode...

[10:19:07 AM] Found 0 errors. Watching for file changes.

^C

Only exits after a third ^C:

▲ 👟  pnpm run dev:ts

> app@0.0.12 dev:ts /my/repo/path
> tsc -b -w --preserveWatchOutput

[10:19:06 AM] Starting compilation in watch mode...

[10:19:07 AM] Found 0 errors. Watching for file changes.

^C^C^C

Exits immediately, as expected:

▲ 👟 pnpm exec tsc -b -w --preserveWatchOutput
[10:20:10 AM] Starting compilation in watch mode...

[10:20:10 AM] Found 0 errors. Watching for file changes.

^C

[rafaelnajman]

Confirming this on 7.0.2 and on 7.1.0-dev.20260908.1, macOS 15 arm64, with two consequences I didn't see covered here. I filed #64196 before finding this issue and am closing that one — moving the detail here.

The interrupted compile exits 0. Clean 30,051-file / 1.9 M-line project, zero errors, 34 s baseline compile, signalled 10 s in:

Signal	Exit	Result
SIGINT	0	ran to completion (48 s), full --extendedDiagnostics block printed
SIGTERM	0	ran to completion (49 s), full block printed
SIGHUP	129	terminated at 10 s, no diagnostics
SIGINT, idle --watch	0	exits in ~1 s, as expected

"Ran to completion" isn't inferred from wall-clock timing — only a finished compile prints the Files / Lines / Check time / Total time block. SIGHUP is the useful control: it isn't in the signal.NotifyContext list, so it keeps its default disposition and dies instantly, which confirms the signals are reaching the process.

The exit code matters beyond Ctrl-C being unresponsive: anything that terminates tsc — a CI job timeout, a cancelled workflow, a runner stopping a task — gets 0 back and records the build as having passed.

Parallel build runners leak compilers. pnpm -r --parallel sends SIGTERM to the remaining packages when one fails, then exits. They ignore it, get reparented to PID 1, and keep compiling — uninterruptible, and no longer on the shell's job table so Ctrl-C can't reach them either. In our 17-service monorepo one failing service left the other 16 compiling, several above 2 GB each, until the machine ran out of memory. pnpm 12 escalates to SIGKILL and reaps them; pnpm 11 does not.

A self-contained repro (generator + signalling script) is in #64196.

One note for whoever picks this up: microsoft/typescript-go#4592 was closed unmerged on 2026-08-17 when typescript-go was archived, rather than on its merits — the migration notice said open PRs would be closed and need re-opening here, and that hasn't happened yet.