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
Init repo1:
$ hg init repo1
$ cd repo1
$ echo "some text" > a
$ hg add
adding a
$ hg ci -m first
$ cat .hg/store/fncache | sort
data/a.i
Testing a.i/b:
$ mkdir a.i
$ echo "some other text" > a.i/b
$ hg add
adding a.i/b (glob)
$ hg ci -m second
$ cat .hg/store/fncache | sort
data/a.i
data/a.i.hg/b.i
Testing a.i.hg/c:
$ mkdir a.i.hg
$ echo "yet another text" > a.i.hg/c
$ hg add
adding a.i.hg/c (glob)
$ hg ci -m third
$ cat .hg/store/fncache | sort
data/a.i
data/a.i.hg.hg/c.i
data/a.i.hg/b.i
Testing verify:
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 3 changesets, 3 total revisions
$ rm .hg/store/fncache
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
warning: revlog 'data/a.i' not in fncache!
warning: revlog 'data/a.i.hg/c.i' not in fncache!
warning: revlog 'data/a.i/b.i' not in fncache!
3 files, 3 changesets, 3 total revisions
3 warnings encountered!
hint: run "hg debugrebuildfncache" to recover from corrupt fncache
Follow the hint to make sure it works
$ hg debugrebuildfncache
adding data/a.i
adding data/a.i.hg/c.i
adding data/a.i/b.i
3 items added, 0 removed from fncache
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 3 changesets, 3 total revisions
$ cd ..
Non store repo:
$ hg --config format.usestore=False init foo
$ cd foo
$ mkdir tst.d
$ echo foo > tst.d/foo
$ hg ci -Amfoo
adding tst.d/foo
$ find .hg | sort
.hg
.hg/00changelog.i
.hg/00manifest.i
.hg/cache
.hg/cache/branch2-served
.hg/cache/rbc-names-v1
.hg/cache/rbc-revs-v1
.hg/data
.hg/data/tst.d.hg
.hg/data/tst.d.hg/foo.i
.hg/dirstate
.hg/last-message.txt
.hg/phaseroots
.hg/requires
.hg/undo
.hg/undo.backup.dirstate
.hg/undo.backupfiles
.hg/undo.bookmarks
.hg/undo.branch
.hg/undo.desc
.hg/undo.dirstate
.hg/undo.phaseroots
$ cd ..
Non fncache repo:
$ hg --config format.usefncache=False init bar
$ cd bar
$ mkdir tst.d
$ echo foo > tst.d/Foo
$ hg ci -Amfoo
adding tst.d/Foo
$ find .hg | sort
.hg
.hg/00changelog.i
.hg/cache
.hg/cache/branch2-served
.hg/cache/rbc-names-v1
.hg/cache/rbc-revs-v1
.hg/dirstate
.hg/last-message.txt
.hg/requires
.hg/store
.hg/store/00changelog.i
.hg/store/00manifest.i
.hg/store/data
.hg/store/data/tst.d.hg
.hg/store/data/tst.d.hg/_foo.i
.hg/store/phaseroots
.hg/store/undo
.hg/store/undo.backupfiles
.hg/store/undo.phaseroots
.hg/undo.backup.dirstate
.hg/undo.bookmarks
.hg/undo.branch
.hg/undo.desc
.hg/undo.dirstate
$ cd ..
Encoding of reserved / long paths in the store
$ hg init r2
$ cd r2
$ cat <<EOF > .hg/hgrc
> [ui]
> portablefilenames = ignore
> EOF
$ hg import -q --bypass - <<EOF
> # HG changeset patch
> # User test
> # Date 0 0
> # Node ID 1c7a2f7cb77be1a0def34e4c7cabc562ad98fbd7
> # Parent 0000000000000000000000000000000000000000
> 1
>
> diff --git a/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz b/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz
> new file mode 100644
> --- /dev/null
> +++ b/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz
> @@ -0,0 +1,1 @@
> +foo
> diff --git a/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT b/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT
> new file mode 100644
> --- /dev/null
> +++ b/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT
> @@ -0,0 +1,1 @@
> +foo
> diff --git a/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt b/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt
> new file mode 100644
> --- /dev/null
> +++ b/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt
> @@ -0,0 +1,1 @@
> +foo
> diff --git a/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c b/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c
> new file mode 100644
> --- /dev/null
> +++ b/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c
> @@ -0,0 +1,1 @@
> +foo
> diff --git a/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider b/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider
> new file mode 100644
> --- /dev/null
> +++ b/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider
> @@ -0,0 +1,1 @@
> +foo
> EOF
$ find .hg/store -name *.i | sort
.hg/store/00changelog.i
.hg/store/00manifest.i
.hg/store/data/bla.aux/pr~6e/_p_r_n/lpt/co~6d3/nu~6c/coma/foo._n_u_l/normal.c.i
.hg/store/dh/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxx168e07b38e65eff86ab579afaaa8e30bfbe0f35f.i
.hg/store/dh/au~78/second/x.prn/fourth/fi~3afth/sixth/seventh/eighth/nineth/tenth/loremia20419e358ddff1bf8751e38288aff1d7c32ec05.i
.hg/store/dh/enterpri/openesba/contrib-/corba-bc/netbeans/wsdlexte/src/main/java/org.net7018f27961fdf338a598a40c4683429e7ffb9743.i
.hg/store/dh/project_/resource/anotherl/followed/andanoth/andthenanextremelylongfilename0d8e1f4187c650e2f1fdca9fd90f786bc0976b6b.i
$ cd ..
Aborting lock does not prevent fncache writes
$ cat > exceptionext.py <<EOF
> import os
> from mercurial import commands, error
> from mercurial.extensions import wrapcommand, wrapfunction
>
> def lockexception(orig, vfs, lockname, wait, releasefn, *args, **kwargs):
> def releasewrap():
> l.held = False # ensure __del__ is a noop
> raise error.Abort("forced lock failure")
> l = orig(vfs, lockname, wait, releasewrap, *args, **kwargs)
> return l
>
> def reposetup(ui, repo):
> wrapfunction(repo, '_lock', lockexception)
>
> cmdtable = {}
>
> # wrap "commit" command to prevent wlock from being '__del__()'-ed
> # at the end of dispatching (for intentional "forced lcok failure")
> def commitwrap(orig, ui, repo, *pats, **opts):
> repo = repo.unfiltered() # to use replaced repo._lock certainly
> wlock = repo.wlock()
> try:
> return orig(ui, repo, *pats, **opts)
> finally:
> # multiple 'relase()' is needed for complete releasing wlock,
> # because "forced" abort at last releasing store lock
> # prevents wlock from being released at same 'lockmod.release()'
> for i in range(wlock.held):
> wlock.release()
>
> def extsetup(ui):
> wrapcommand(commands.table, "commit", commitwrap)
> EOF
$ extpath=`pwd`/exceptionext.py
$ hg init fncachetxn
$ cd fncachetxn
$ printf "[extensions]\nexceptionext=$extpath\n" >> .hg/hgrc
$ touch y
$ hg ci -qAm y
abort: forced lock failure
[255]
$ cat .hg/store/fncache
data/y.i
Aborting transaction prevents fncache change
$ cat > ../exceptionext.py <<EOF
> import os
> from mercurial import commands, error, localrepo
> from mercurial.extensions import wrapfunction
>
> def wrapper(orig, self, *args, **kwargs):
> tr = orig(self, *args, **kwargs)
> def fail(tr):
> raise error.Abort("forced transaction failure")
> # zzz prefix to ensure it sorted after store.write
> tr.addfinalize('zzz-forcefails', fail)
> return tr
>
> def uisetup(ui):
> wrapfunction(localrepo.localrepository, 'transaction', wrapper)
>
> cmdtable = {}
>
> EOF
$ rm -f "${extpath}c"
$ touch z
$ hg ci -qAm z
transaction abort!
rollback completed
abort: forced transaction failure
[255]
$ cat .hg/store/fncache
data/y.i
Aborted transactions can be recovered later
$ cat > ../exceptionext.py <<EOF
> import os
> from mercurial import commands, error, transaction, localrepo
> from mercurial.extensions import wrapfunction
>
> def trwrapper(orig, self, *args, **kwargs):
> tr = orig(self, *args, **kwargs)
> def fail(tr):
> raise error.Abort("forced transaction failure")
> # zzz prefix to ensure it sorted after store.write
> tr.addfinalize('zzz-forcefails', fail)
> return tr
>
> def abortwrapper(orig, self, *args, **kwargs):
> raise error.Abort("forced transaction failure")
>
> def uisetup(ui):
> wrapfunction(localrepo.localrepository, 'transaction', trwrapper)
> wrapfunction(transaction.transaction, '_abort', abortwrapper)
>
> cmdtable = {}
>
> EOF
$ rm -f "${extpath}c"
$ hg up -q 1
$ touch z
$ hg ci -qAm z 2>/dev/null
[255]
$ cat .hg/store/fncache | sort
data/y.i
data/z.i
$ hg recover
rolling back interrupted transaction
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
$ cat .hg/store/fncache
data/y.i
$ cd ..
debugrebuildfncache does nothing unless repo has fncache requirement
$ hg --config format.usefncache=false init nofncache
$ cd nofncache
$ hg debugrebuildfncache
(not rebuilding fncache because repository does not support fncache)
$ cd ..
debugrebuildfncache works on empty repository
$ hg init empty
$ cd empty
$ hg debugrebuildfncache
fncache already up to date
$ cd ..
debugrebuildfncache on an up to date repository no-ops
$ hg init repo
$ cd repo
$ echo initial > foo
$ echo initial > .bar
$ hg commit -A -m initial
adding .bar
adding foo
$ cat .hg/store/fncache | sort
data/.bar.i
data/foo.i
$ hg debugrebuildfncache
fncache already up to date
debugrebuildfncache restores deleted fncache file
$ rm -f .hg/store/fncache
$ hg debugrebuildfncache
adding data/.bar.i
adding data/foo.i
2 items added, 0 removed from fncache
$ cat .hg/store/fncache | sort
data/.bar.i
data/foo.i
Rebuild after rebuild should no-op
$ hg debugrebuildfncache
fncache already up to date
A single missing file should get restored, an extra file should be removed
$ cat > .hg/store/fncache << EOF
> data/foo.i
> data/bad-entry.i
> EOF
$ hg debugrebuildfncache
removing data/bad-entry.i
adding data/.bar.i
1 items added, 1 removed from fncache
$ cat .hg/store/fncache | sort
data/.bar.i
data/foo.i
$ cd ..
Try a simple variation without dotencode to ensure fncache is ignorant of encoding
$ hg --config format.dotencode=false init nodotencode
$ cd nodotencode
$ echo initial > foo
$ echo initial > .bar
$ hg commit -A -m initial
adding .bar
adding foo
$ cat .hg/store/fncache | sort
data/.bar.i
data/foo.i
$ rm .hg/store/fncache
$ hg debugrebuildfncache
adding data/.bar.i
adding data/foo.i
2 items added, 0 removed from fncache
$ cat .hg/store/fncache | sort
data/.bar.i
data/foo.i