Not all machines support signal.alarm. Our timeout code makes an effort to function without signal.alarm when possible. Timeout is much less robust without signal.alarm, but is still useful in many circumstances.
<rdar://problem/73769605>
Created attachment 418766 [details] Patch
Works for me locally with Python 3 on Windows! There are other cases where signal.SIGKILL is used which isn't present in Python for Windows so some more cross platform fixes should probably happen around usage of signal.
Looks like there are a few in task_pool.py and our mock popen code. We might also need to address this in webkitpy/common/interrupt_debugging.py, but that would have broken layout tests in Python 2 on Windows machines as well.
Created attachment 418788 [details] Patch
rs=me
Created attachment 418896 [details] Patch for landing
Committed r272169: <https://trac.webkit.org/changeset/272169> All reviewed patches have been landed. Closing bug and clearing flags on attachment 418896 [details].