commands: make commit acquire locks before processing (issue4368)
Before this patch, "hg commit" (process A) executes steps below:
1. get current branch heads via 'repo.branchheads()'
- cache 'repo.changelog'
2. invoke 'repo.commit()'
3. acquire wlock
- invalidate 'repo.dirstate'
4. access 'repo.dirstate'
- re-read '.hg/dirstate'
- check validity of parent revisions with 'repo.changelog'
5. invoke 'repo.commitctx()'
6. acquire store lock (slock)
- invalidate 'repo.changelog'
7. do committing
8. release slock
9. release wlock
10. check new branch head (via 'cmdutil.commitstatus()')
If acquisition of wlock at (3) above waits for another "hg commit"
(process B) or so running parallelly to release wlock, process A
causes creating orphan revision, because:
- '.hg/dirstate' refers the revision, which is newly added by
process B, as its parent
- but already cached 'repo.changelog' doesn't contain such revision
- therefore, validating parents of '.hg/dirstate' at (4) above
replaces such revision with 'nullid'
Then, process A creates "orphan" revision, of which parent is "null"
revision.
In addition to it, "created new head" may be shown at the end of
process A unintentionally, if store is updated parallelly, because
both getting branch heads (1) and checking new branch head (10) are
executed outside slock scope.
To avoid this issue, this patch makes "hg commit" acquire wlock and
slock before processing.
This patch resolves the issue between "hg commit" processes, but not
one between "hg commit" and other commands. Subsequent patches resolve
the latter.
Even after this patch, there are still corner case problems below:
- filecache may overlook changes of '.hg/dirstate', and it causes
similar issue (see below for detail)
https://bz.mercurial-scm.org/show_bug.cgi?id=4368#c10
- 3rd party extension may cause similar issue, if it directly uses
'repo.commit()' without acquisition of wlock and slock
This can be fixed by acquisition of slock at the beginning of
'repo.commit()', but it seems suitable for "default" branch
In fact, acquisition of slock itself is already introduced at
"default" branch by 4414d500604f, but acquisition is not at the
beginning of 'repo.commit()'.
This patch also changes some tests:
- test-fncache.t needs this tricky wrapping, to release (= forced
failure of) wlock certainly
- order of "hg commit" output is changed by widening scope of locks,
because some hooks are fired after releasing wlock
$ cat >> $HGRCPATH <<EOF
> [extensions]
> convert =
> [convert]
> hg.saverev = yes
> EOF
$ glog()
> {
> hg -R "$1" log -G --template '{rev} "{desc}" files: {files}\n'
> }
$ hg init source
$ cd source
$ echo a > a
$ echo b > b
$ echo f > f
$ hg ci -d '0 0' -qAm '0: add a b f'
$ echo c > c
$ hg move f d
$ hg ci -d '1 0' -qAm '1: add c, move f to d'
$ hg copy a e
$ echo b >> b
$ hg ci -d '2 0' -qAm '2: copy e from a, change b'
$ hg up -C 0
2 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ echo a >> a
$ hg ci -d '3 0' -qAm '3: change a'
$ hg merge
merging a and e to e
3 files updated, 1 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -d '4 0' -qAm '4: merge 2 and 3'
$ echo a >> a
$ hg ci -d '5 0' -qAm '5: change a'
$ cd ..
Convert from null revision
$ hg convert --config convert.hg.startrev=null source full
initializing destination full repository
scanning source...
sorting...
converting...
5 0: add a b f
4 1: add c, move f to d
3 2: copy e from a, change b
2 3: change a
1 4: merge 2 and 3
0 5: change a
$ glog full
o 5 "5: change a" files: a
|
o 4 "4: merge 2 and 3" files: e f
|\
| o 3 "3: change a" files: a
| |
o | 2 "2: copy e from a, change b" files: b e
| |
o | 1 "1: add c, move f to d" files: c d f
|/
o 0 "0: add a b f" files: a b f
$ rm -Rf full
Convert from zero revision
$ hg convert --config convert.hg.startrev=0 source full
initializing destination full repository
scanning source...
sorting...
converting...
5 0: add a b f
4 1: add c, move f to d
3 2: copy e from a, change b
2 3: change a
1 4: merge 2 and 3
0 5: change a
$ glog full
o 5 "5: change a" files: a
|
o 4 "4: merge 2 and 3" files: e f
|\
| o 3 "3: change a" files: a
| |
o | 2 "2: copy e from a, change b" files: b e
| |
o | 1 "1: add c, move f to d" files: c d f
|/
o 0 "0: add a b f" files: a b f
Convert from merge parent
$ hg convert --config convert.hg.startrev=1 source conv1
initializing destination conv1 repository
scanning source...
sorting...
converting...
3 1: add c, move f to d
2 2: copy e from a, change b
1 4: merge 2 and 3
0 5: change a
$ glog conv1
o 3 "5: change a" files: a
|
o 2 "4: merge 2 and 3" files: a e
|
o 1 "2: copy e from a, change b" files: b e
|
o 0 "1: add c, move f to d" files: a b c d
$ cd conv1
$ hg up -q
Check copy preservation
$ hg st -C --change 2 e
M e
$ hg st -C --change 1 e
A e
a
$ hg st -C --change 0 a
A a
(It seems like a bug in log that the following doesn't show rev 1.)
$ hg log --follow --copies e
changeset: 2:82bbac3d2cf4
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: 4: merge 2 and 3
changeset: 0:23c3be426dce
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: 1: add c, move f to d
Check copy removal on missing parent
$ hg log --follow --copies d
changeset: 0:23c3be426dce
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: 1: add c, move f to d
$ hg cat -r tip a b
a
a
a
b
b
$ hg -q verify
$ cd ..
Convert from merge
$ hg convert --config convert.hg.startrev=4 source conv4
initializing destination conv4 repository
scanning source...
sorting...
converting...
1 4: merge 2 and 3
0 5: change a
$ glog conv4
o 1 "5: change a" files: a
|
o 0 "4: merge 2 and 3" files: a b c d e
$ cd conv4
$ hg up -C
5 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg cat -r tip a b
a
a
a
b
b
$ hg -q verify
$ cd ..
Convert from revset in convert.hg.revs
$ hg convert --config convert.hg.revs='3:4+0' source revsetrepo
initializing destination revsetrepo repository
scanning source...
sorting...
converting...
2 0: add a b f
1 3: change a
0 4: merge 2 and 3
$ glog revsetrepo
o 2 "4: merge 2 and 3" files: b c d e f
|
o 1 "3: change a" files: a
|
o 0 "0: add a b f" files: a b f
Convert from specified revs
$ hg convert --rev 3 --rev 2 source multiplerevs
initializing destination multiplerevs repository
scanning source...
sorting...
converting...
3 0: add a b f
2 1: add c, move f to d
1 2: copy e from a, change b
0 3: change a
$ glog multiplerevs
o 3 "3: change a" files: a
|
| o 2 "2: copy e from a, change b" files: b e
| |
| o 1 "1: add c, move f to d" files: c d f
|/
o 0 "0: add a b f" files: a b f