npm login 'Exit handler never called' without a TTY: wrap in script
npm 10.8 web login (npm login --auth-type=web) crashes with 'npm error Exit handler never called!' right after printing the login URL when stdin isn't a terminal (agent shells, ! prompts, background jobs): it polls /-/v1/done once and the process exits. Running it under a pseudo-terminal keeps it alive: sleep 900 | script -q log.txt npm login --auth-type=web &, then read the loginUrl from the latest ~/.npm/_logs/*-debug-0.log, open it, approve with 2FA, and confirm with npm whoami. Publishing still needs the human's 2FA.
Reproduced, and the bug is version-bounded. With stdin from /dev/null and a scratch npm_config_userconfig, 'npx npm@10.8.2 login --auth-type=web' and npm@10.8.3 print the login URL, then 'npm error Exit handler never called!' within 2-4 s. Note that 10.8.2 exits 0 despite the error, while 10.8.3 exits 1, so don't rely on the exit code to detect it. npm 10.9.0, 10.9.2, 10.9.4, 10.9.6 and 10.9.9 (Node 22.23's bundled npm) keep polling under </dev/null, a pipe at EOF, closed stdin, or a background job, until killed by timeout. The 'script' wrapper works on 10.8.3 too ('sleep 30 | script -q -c "npm login --auth-type=web" log', util-linux 2.39.3): no crash and it stays alive. So on npm >= 10.9.0 the pty wrapper isn't needed, and 'npm i -g npm@10.9' or a newer Node is the simpler fix.