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 bzr
$ . "$TESTDIR/bzr-definitions"
empty directory
$ mkdir test-empty
$ cd test-empty
$ bzr init -q source
$ cd source
$ echo content > a
$ bzr add -q a
$ bzr commit -q -m 'Initial add'
$ mkdir empty
$ bzr add -q empty
$ bzr commit -q -m 'Empty directory added'
$ echo content > empty/something
$ bzr add -q empty/something
$ bzr commit -q -m 'Added file into directory'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
2 Initial add
1 Empty directory added
0 Added file into directory
$ manifest source-hg 1
% manifest of 1
644 a
$ manifest source-hg tip
% manifest of tip
644 a
644 empty/something
$ cd ..
directory renames
$ mkdir test-dir-rename
$ cd test-dir-rename
$ bzr init -q source
$ cd source
$ mkdir tpyo
$ echo content > tpyo/something
$ bzr add -q tpyo
$ bzr commit -q -m 'Added directory'
$ bzr mv tpyo typo
tpyo => typo
$ bzr commit -q -m 'Oops, typo'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added directory
0 Oops, typo
$ manifest source-hg 0
% manifest of 0
644 tpyo/something
$ manifest source-hg tip
% manifest of tip
644 typo/something
$ cd ..
nested directory renames
$ mkdir test-nested-dir-rename
$ cd test-nested-dir-rename
$ bzr init -q source
$ cd source
$ mkdir -p firstlevel/secondlevel/thirdlevel
$ echo content > firstlevel/secondlevel/file
$ echo this_needs_to_be_there_too > firstlevel/secondlevel/thirdlevel/stuff
$ bzr add -q firstlevel
$ bzr commit -q -m 'Added nested directories'
$ bzr mv firstlevel/secondlevel secondlevel
firstlevel/secondlevel => secondlevel
$ bzr commit -q -m 'Moved secondlevel one level up'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added nested directories
0 Moved secondlevel one level up
$ manifest source-hg tip
% manifest of tip
644 secondlevel/file
644 secondlevel/thirdlevel/stuff
$ cd ..
directory remove
$ mkdir test-dir-remove
$ cd test-dir-remove
$ bzr init -q source
$ cd source
$ mkdir src
$ echo content > src/sourcecode
$ bzr add -q src
$ bzr commit -q -m 'Added directory'
$ bzr rm -q src
$ bzr commit -q -m 'Removed directory'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added directory
0 Removed directory
$ manifest source-hg 0
% manifest of 0
644 src/sourcecode
$ manifest source-hg tip
% manifest of tip
$ cd ..
directory replace
$ mkdir test-dir-replace
$ cd test-dir-replace
$ bzr init -q source
$ cd source
$ mkdir first second
$ echo content > first/file
$ echo morecontent > first/dummy
$ echo othercontent > second/something
$ bzr add -q first second
$ bzr commit -q -m 'Initial layout'
$ bzr mv first/file second/file
first/file => second/file
$ bzr mv first third
first => third
$ bzr commit -q -m 'Some conflicting moves'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial layout
0 Some conflicting moves
$ manifest source-hg tip
% manifest of tip
644 second/file
644 second/something
644 third/dummy
$ cd ..
divergent nested renames (issue3089)
$ mkdir test-divergent-renames
$ cd test-divergent-renames
$ bzr init -q source
$ cd source
$ mkdir -p a/c
$ echo a > a/fa
$ echo c > a/c/fc
$ bzr add -q a
$ bzr commit -q -m 'Initial layout'
$ bzr mv a b
a => b
$ mkdir a
$ bzr add a
add(ed|ing) a (re)
$ bzr mv b/c a/c
b/c => a/c
$ bzr status
added:
a/
renamed:
a/? => b/? (re)
a/c/? => a/c/? (re)
$ bzr commit -q -m 'Divergent renames'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial layout
0 Divergent renames
$ hg -R source-hg st -C --change 1
A b/fa
a/fa
R a/fa
$ hg -R source-hg manifest -r 1
a/c/fc
b/fa
$ cd ..