tests/test-worker.t

match: avoid translating glob to matcher multiple times for large sets

For hgignore with many globs, the resulting regexp might not fit under the 20K
length limit. So the patterns need to be broken up in smaller pieces.

Before this change, the logic was re-starting the full process from scratch
for each smaller pieces, including the translation of globs into regexp.
Effectively doing the work over and over.

If the 20K limit is reached, we are likely in a case where there is many such
glob, so exporting them is especially expensive and we should be careful not
to do that work more than once.

To work around this, we now translate glob to regexp once and for all. Then,
we assemble the resulting individual regexp into valid blocks.

This raises a very significant performance win for large `.hgignore file`:

Before: ! wall 0.153153 comb 0.150000 user 0.150000 sys 0.000000 (median of 66)
After:  ! wall 0.059793 comb 0.060000 user 0.060000 sys 0.000000 (median of 100)

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)'
  Abort: known exception
  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