tests/test-worker.t

rust-performance: introduce FastHashMap type alias for HashMap

Rust's default hashing is slow, because it is meant for preventing collision
attacks.
For all of the current Rust code, we don't care about those attacks, because
if an person with bad intentions has write access to your repo, you have other
issues.

I've chosen to use the TwoXHash crate because it was made by a reputable member
of the Rust community and has very good benchmarks.

For now it does not seem to improve performance by much for the current code,
but it's something else to not worry about when benchmarking code: in a
previous experiment with copytracing in Rust, it accounted for more than 10%
of the time of the entire script.

Differential Revision: https://phab.mercurial-scm.org/D7116

Test UI worker interaction

  $ cat > t.py <<EOF
  > from __future__ import absolute_import, print_function
  > import time
  > from mercurial import (
  >     error,
  >     registrar,
  >     ui as uimod,
  >     worker,
  > )
  > def abort(ui, args):
  >     if args[0] == 0:
  >         # by first worker for test stability
  >         raise error.Abort(b'known exception')
  >     return runme(ui, [])
  > def exc(ui, args):
  >     if args[0] == 0:
  >         # by first worker for test stability
  >         raise Exception('unknown exception')
  >     return runme(ui, [])
  > def runme(ui, args):
  >     for arg in args:
  >         ui.status(b'run\n')
  >         yield 1, arg
  >     time.sleep(0.1) # easier to trigger killworkers code path
  > functable = {
  >     b'abort': abort,
  >     b'exc': exc,
  >     b'runme': runme,
  > }
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'test', [], b'hg test [COST] [FUNC]')
  > def t(ui, repo, cost=1.0, func=b'runme'):
  >     cost = float(cost)
  >     func = functable[func]
  >     ui.status(b'start\n')
  >     runs = worker.worker(ui, cost, func, (ui,), range(8))
  >     for n, i in runs:
  >         pass
  >     ui.status(b'done\n')
  > EOF
  $ abspath=`pwd`/t.py
  $ hg init

Run tests with worker enable by forcing a heigh cost

  $ hg --config "extensions.t=$abspath" test 100000.0
  start
  run
  run
  run
  run
  run
  run
  run
  run
  done

Run tests without worker by forcing a low cost

  $ hg --config "extensions.t=$abspath" test 0.0000001
  start
  run
  run
  run
  run
  run
  run
  run
  run
  done

#if no-windows

Known exception should be caught, but printed if --traceback is enabled

  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
  > test 100000.0 abort 2>&1
  start
  abort: known exception
  [255]

  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
  > test 100000.0 abort --traceback 2>&1 | egrep '(SystemExit|Abort)'
      raise error.Abort(b'known exception')
  mercurial.error.Abort: known exception (py3 !)
  Abort: known exception (no-py3 !)
  SystemExit: 255

Traceback must be printed for unknown exceptions

  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
  > test 100000.0 exc 2>&1 | grep '^Exception'
  Exception: unknown exception

Workers should not do cleanups in all cases

  $ cat > $TESTTMP/detectcleanup.py <<EOF
  > from __future__ import absolute_import
  > import atexit
  > import os
  > import time
  > oldfork = os.fork
  > count = 0
  > parentpid = os.getpid()
  > def delayedfork():
  >     global count
  >     count += 1
  >     pid = oldfork()
  >     # make it easier to test SIGTERM hitting other workers when they have
  >     # not set up error handling yet.
  >     if count > 1 and pid == 0:
  >         time.sleep(0.1)
  >     return pid
  > os.fork = delayedfork
  > def cleanup():
  >     if os.getpid() != parentpid:
  >         os.write(1, 'should never happen\n')
  > atexit.register(cleanup)
  > EOF

  $ hg --config "extensions.t=$abspath" --config worker.numcpus=8 --config \
  > "extensions.d=$TESTTMP/detectcleanup.py" test 100000 abort
  start
  abort: known exception
  [255]

#endif