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.
Journal extension test: tests the share extension support
$ cat >> testmocks.py << EOF
> # mock out util.getuser() and util.makedate() to supply testable values
> import os
> from mercurial import util
> def mockgetuser():
> return 'foobar'
>
> def mockmakedate():
> filename = os.path.join(os.environ['TESTTMP'], 'testtime')
> try:
> with open(filename, 'rb') as timef:
> time = float(timef.read()) + 1
> except IOError:
> time = 0.0
> with open(filename, 'wb') as timef:
> timef.write(str(time))
> return (time, 0)
>
> util.getuser = mockgetuser
> util.makedate = mockmakedate
> EOF
$ cat >> $HGRCPATH << EOF
> [extensions]
> journal=
> share=
> testmocks=`pwd`/testmocks.py
> [remotenames]
> rename.default=remote
> EOF
$ hg init repo
$ cd repo
$ hg bookmark bm
$ touch file0
$ hg commit -Am 'file0 added'
adding file0
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . commit -Am 'file0 added'
5640b525682e bm commit -Am 'file0 added'
A shared working copy initially receives the same bookmarks and working copy
$ cd ..
$ hg share repo shared1
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd shared1
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . share repo shared1
unless you explicitly share bookmarks
$ cd ..
$ hg share --bookmarks repo shared2
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd shared2
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . share --bookmarks repo shared2
5640b525682e bm commit -Am 'file0 added'
Moving the bookmark in the original repository is only shown in the repository
that shares bookmarks
$ cd ../repo
$ touch file1
$ hg commit -Am "file1 added"
adding file1
$ cd ../shared1
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . share repo shared1
$ cd ../shared2
$ hg journal --all
previous locations of the working copy and bookmarks:
6432d239ac5d bm commit -Am 'file1 added'
5640b525682e . share --bookmarks repo shared2
5640b525682e bm commit -Am 'file0 added'
But working copy changes are always 'local'
$ cd ../repo
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark bm)
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . up 0
6432d239ac5d . commit -Am 'file1 added'
6432d239ac5d bm commit -Am 'file1 added'
5640b525682e . commit -Am 'file0 added'
5640b525682e bm commit -Am 'file0 added'
$ cd ../shared2
$ hg journal --all
previous locations of the working copy and bookmarks:
6432d239ac5d bm commit -Am 'file1 added'
5640b525682e . share --bookmarks repo shared2
5640b525682e bm commit -Am 'file0 added'
$ hg up tip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg journal
previous locations of '.':
5640b525682e up 0
6432d239ac5d up tip
5640b525682e share --bookmarks repo shared2
Unsharing works as expected; the journal remains consistent
$ cd ../shared1
$ hg unshare
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . share repo shared1
$ cd ../shared2
$ hg unshare
$ hg journal --all
previous locations of the working copy and bookmarks:
5640b525682e . up 0
6432d239ac5d . up tip
6432d239ac5d bm commit -Am 'file1 added'
5640b525682e . share --bookmarks repo shared2
5640b525682e bm commit -Am 'file0 added'
New journal entries in the source repo no longer show up in the other working copies
$ cd ../repo
$ hg bookmark newbm -r tip
$ hg journal newbm
previous locations of 'newbm':
6432d239ac5d bookmark newbm -r tip
$ cd ../shared2
$ hg journal newbm
previous locations of 'newbm':
no recorded locations
This applies for both directions
$ hg bookmark shared2bm -r tip
$ hg journal shared2bm
previous locations of 'shared2bm':
6432d239ac5d bookmark shared2bm -r tip
$ cd ../repo
$ hg journal shared2bm
previous locations of 'shared2bm':
no recorded locations