[nathanwhit]

Summary

Allow Node-compatible TTY stdio writes to drain and then stop keeping Deno alive, without changing the observable ref state of the underlying stdio handle where that handle is exposed.

Adds a PTY integration regression for a large process.stderr.write() that verifies the write callback runs and the process exits. On platforms that expose process.stderr._handle.hasRef(), it also verifies the handle remains ref'ed before and inside the callback.

Root Cause

uv_tty_init() creates TTY handles with UV_HANDLE_REF, matching Node's observable process.stderr._handle.hasRef() === true behavior for stdio TTYs where _handle is exposed.

Deno's uv_compat write path also marks TTY handles UV_HANDLE_ACTIVE via ensure_tty_registered(). Plain TTY writes drained their callbacks, but the normal write-drain path did not clear UV_HANDLE_ACTIVE; only the shutdown path deactivated the handle. Since loop liveness checks count handles that are both active and ref'ed, an idle stdio TTY write handle could keep Deno alive forever after all JS and children had finished.

The fix deactivates TTY handles once there is no pending read, write, or shutdown work. It leaves UV_HANDLE_REF untouched, so _handle.hasRef() remains Node-compatible while idle inactive handles no longer keep the loop alive.

Redirected output avoids the TTY stream path, which is why the same script exited with stdout/stderr redirected.

Validation

• ./tools/format.js ext/node/polyfills/process.ts libs/core/uv_compat/tty.rs tests/integration/run_tests.rs tests/testdata/run/process_stderr_tty_write_exit.js
• cargo test --test integration process_stderr_tty_write_exit
• cargo test -p deno_core uv_compat
• ./tools/lint.js
• Manual PTY reduction: large process.stderr.write() exits and reports _handle.hasRef() as true before and inside the callback on macOS
• Manual PTY validation in ../v8x: target/debug/deno run -A tests/harness/run.mjs rusty_v8 quickjs --rescue exits cleanly with pass=267 fail=0 skip=0
• CI: test integration (1/2) debug windows-x86_64 passed on head 3a9f366bf34b16ad3b0c12117233460c5320e2a0