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
#if no-outer-repo
no repo
$ hg id
abort: there is no Mercurial repository here (.hg not found)
[255]
#endif
create repo
$ hg init test
$ cd test
$ echo a > a
$ hg ci -Ama
adding a
basic id usage
$ hg id
cb9a9f314b8b tip
$ hg id --debug
cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b tip
$ hg id -q
cb9a9f314b8b
$ hg id -v
cb9a9f314b8b tip
with options
$ hg id -r.
cb9a9f314b8b tip
$ hg id -n
0
$ hg id -t
tip
$ hg id -b
default
$ hg id -i
cb9a9f314b8b
$ hg id -n -t -b -i
cb9a9f314b8b 0 default tip
with modifications
$ echo b > a
$ hg id -n -t -b -i
cb9a9f314b8b+ 0+ default tip
other local repo
$ cd ..
$ hg -R test id
cb9a9f314b8b+ tip
#if no-outer-repo
$ hg id test
cb9a9f314b8b+ tip
#endif
with remote http repo
$ cd test
$ hg serve -p $HGPORT1 -d --pid-file=hg.pid
$ cat hg.pid >> $DAEMON_PIDS
$ hg id http://localhost:$HGPORT1/
cb9a9f314b8b
remote with rev number?
$ hg id -n http://localhost:$HGPORT1/
abort: can't query remote revision number, branch, or tags
[255]
remote with tags?
$ hg id -t http://localhost:$HGPORT1/
abort: can't query remote revision number, branch, or tags
[255]
remote with branch?
$ hg id -b http://localhost:$HGPORT1/
abort: can't query remote revision number, branch, or tags
[255]
test bookmark support
$ hg bookmark Y
$ hg bookmark Z
$ hg bookmarks
Y 0:cb9a9f314b8b
* Z 0:cb9a9f314b8b
$ hg id
cb9a9f314b8b+ tip Y/Z
$ hg id --bookmarks
Y Z
test remote identify with bookmarks
$ hg id http://localhost:$HGPORT1/
cb9a9f314b8b Y/Z
$ hg id --bookmarks http://localhost:$HGPORT1/
Y Z
$ hg id -r . http://localhost:$HGPORT1/
cb9a9f314b8b Y/Z
$ hg id --bookmarks -r . http://localhost:$HGPORT1/
Y Z
test invalid lookup
$ hg id -r noNoNO http://localhost:$HGPORT1/
abort: unknown revision 'noNoNO'!
[255]
Make sure we do not obscure unknown requires file entries (issue2649)
$ echo fake >> .hg/requires
$ hg id
abort: repository requires features unknown to this Mercurial: fake!
(see https://mercurial-scm.org/wiki/MissingRequirement for more information)
[255]
$ cd ..
#if no-outer-repo
$ hg id test
abort: repository requires features unknown to this Mercurial: fake!
(see https://mercurial-scm.org/wiki/MissingRequirement for more information)
[255]
#endif