lock: block signal interrupt while making a lock file
On Windows where symlink isn't supported, util.makelock() could leave an empty
file if interrupted immediately after os.open(). This empty lock never dies
as it has no process id recorded.
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
# an interrupt may occur here
os.write(ld, info)
os.close(ld)
This was a long-standing bug of TortoiseHg which runs a command-server and
kills it by CTRL_C_EVENT, reported by random Windows users.
https://bitbucket.org/tortoisehg/thg/issues/4873/#comment-
43591129
At first, I tried to fix makelock() to clean up a stale lock file, which
turned out to be hard because any instructions may be interrupted by a
signal.
ld = None
try:
# CALL_FUNCTION # os.open(...)
# an interrupt may occur here
# STORE_FAST # ld = ...
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
os.write(ld, info)
...
return True
except:
if ld:
...
os.unlink(pathname)
return False
So I decided to block signals by temporarily replacing the signal handlers
so makelcok() and held = 1 will never be interrupted.
Many thanks to Fernando Najera for investigating the issue.
=====================
Test workflow options
=====================
$ . "$TESTDIR/testlib/obsmarker-common.sh"
Test single head enforcing - Setup
=============================================
$ cat << EOF >> $HGRCPATH
> [experimental]
> evolution = all
> EOF
$ hg init single-head-server
$ cd single-head-server
$ cat <<EOF >> .hg/hgrc
> [phases]
> publish = no
> [experimental]
> single-head-per-branch = yes
> EOF
$ mkcommit ROOT
$ mkcommit c_dA0
$ cd ..
$ hg clone single-head-server client
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test single head enforcing - with branch only
---------------------------------------------
$ cd client
continuing the current defaultbranch
$ mkcommit c_dB0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
creating a new branch
$ hg up 'desc("ROOT")'
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg branch branch_A
marked working directory as branch branch_A
(branches are permanent and global, did you want a bookmark?)
$ mkcommit c_aC0
$ hg push --new-branch
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
Create a new head on the default branch
$ hg up 'desc("c_dA0")'
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dD0
created new head
$ hg push -f
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
transaction abort!
rollback completed
abort: rejecting multiple heads on branch "default"
(2 heads: 286d02a6e2a2 9bf953aa81f6)
[255]
remerge them
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_dE0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
Test single head enforcing - after rewrite
------------------------------------------
$ mkcommit c_dF0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
$ hg commit --amend -m c_dF1
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 1 files (+1 heads)
1 new obsolescence markers
obsoleted 1 changesets
Check it does to interfer with strip
------------------------------------
setup
$ hg branch branch_A --force
marked working directory as branch branch_A
$ mkcommit c_aG0
created new head
$ hg update 'desc("c_dF1")'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dH0
$ hg update 'desc("c_aG0")'
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_aI0
$ hg log -G
@ changeset: 10:49003e504178
|\ branch: branch_A
| | tag: tip
| | parent: 8:a33fb808fb4b
| | parent: 3:840af1c6bc88
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: c_aI0
| |
| | o changeset: 9:fe47ea669cea
| | | parent: 7:99a2dc242c5d
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: c_dH0
| | |
| o | changeset: 8:a33fb808fb4b
| |/ branch: branch_A
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: c_aG0
| |
| o changeset: 7:99a2dc242c5d
| | parent: 5:6ed1df20edb1
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: c_dF1
| |
| o changeset: 5:6ed1df20edb1
| |\ parent: 4:9bf953aa81f6
| | | parent: 2:286d02a6e2a2
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: c_dE0
| | |
| | o changeset: 4:9bf953aa81f6
| | | parent: 1:134bc3852ad2
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: c_dD0
| | |
o | | changeset: 3:840af1c6bc88
| | | branch: branch_A
| | | parent: 0:ea207398892e
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: c_aC0
| | |
| o | changeset: 2:286d02a6e2a2
| |/ user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: c_dB0
| |
| o changeset: 1:134bc3852ad2
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: c_dA0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
actual stripping
$ hg strip --config extensions.strip= --rev 'desc("c_dH0")'
saved backup bundle to $TESTTMP/client/.hg/strip-backup/fe47ea669cea-a41bf5a9-backup.hg
warning: ignoring unknown working parent 49003e504178!