tests/test-schemes.t

commandserver: add new forking server implemented without using SocketServer

SocketServer.ForkingMixIn of Python 2.x has a couple of issues, such as:

 - race condition that leads to 100% CPU usage (Python 2.6)
   https://bugs.python.org/issue21491
 - can't wait for children belonging to different process groups (Python 2.6)
 - leaves at least one zombie process (Python 2.6, 2.7)
   https://bugs.python.org/issue11109

The first two are critical because we do setpgid(0, 0) in child process to
isolate terminal signals. The last one isn't, but ForkingMixIn seems to be
doing silly. So there are two choices:

 a) backport and maintain SocketServer until we can drop support for Python 2.x
 b) replace SocketServer by simpler one and eliminate glue codes

I chose (b) because it's great time for getting rid of utterly complicated
SocketServer stuff, and preparing for future move towards prefork service.

New unixforkingservice is implemented loosely based on chg 531f8ef64be6. It
is monolithic but much simpler than SocketServer. unixservicehandler provides
customizing points for chg, and it will be shared with future prefork service.

Old unixservice class is still used by chgserver. It will be removed later.

Thanks to Jun Wu for investigating these issues.

#require serve

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > schemes=
  > 
  > [schemes]
  > l = http://localhost:$HGPORT/
  > parts = http://{1}:$HGPORT/
  > z = file:\$PWD/
  > EOF
  $ hg init test
  $ cd test
  $ echo a > a
  $ hg ci -Am initial
  adding a

invalid scheme

  $ hg log -R z:z
  abort: no '://' in scheme url 'z:z'
  [255]

http scheme

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg incoming l://
  comparing with l://
  searching for changes
  no changes found
  [1]

check that {1} syntax works

  $ hg incoming --debug parts://localhost
  using http://localhost:$HGPORT/
  sending capabilities command
  comparing with parts://localhost/
  query 1; heads
  sending batch command
  searching for changes
  all remote heads known locally
  no changes found
  [1]

check that paths are expanded

  $ PWD=`pwd` hg incoming z://
  comparing with z://
  searching for changes
  no changes found
  [1]

check that debugexpandscheme outputs the canonical form

  $ hg debugexpandscheme bb://user/repo
  https://bitbucket.org/user/repo

expanding an unknown scheme emits the input

  $ hg debugexpandscheme foobar://this/that
  foobar://this/that

expanding a canonical URL emits the input

  $ hg debugexpandscheme https://bitbucket.org/user/repo
  https://bitbucket.org/user/repo

errors

  $ cat errors.log

  $ cd ..