revlog: skeleton support for version 2 revlogs
There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.
It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.
This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.
An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.
To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.
Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.
There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.
setup
$ cat >> $HGRCPATH <<EOF
> [extensions]
> blackbox=
> mock=$TESTDIR/mockblackbox.py
> mq=
> [alias]
> confuse = log --limit 3
> EOF
$ hg init blackboxtest
$ cd blackboxtest
command, exit codes, and duration
$ echo a > a
$ hg add a
$ hg blackbox --config blackbox.dirty=True
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000+ (5000)> blackbox
alias expansion is logged
$ hg confuse
$ hg blackbox
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000+ (5000)> blackbox
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000+ (5000)> blackbox --config *blackbox.dirty=True* exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> confuse
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> alias 'confuse' expands to 'log --limit 3'
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> confuse exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox
incoming change tracking
create two heads to verify that we only see one change in the log later
$ hg commit -ma
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo b > b
$ hg commit -Amb
adding b
created new head
clone, commit, pull
$ hg clone . ../blackboxtest2
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo c > c
$ hg commit -Amc
adding c
$ cd ../blackboxtest2
$ hg pull
pulling from $TESTTMP/blackboxtest (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
$ hg blackbox -l 6
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated served branch cache in * seconds (glob)
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote served branch cache with 1 labels and 2 nodes
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> 1 incoming changes - new heads: d02f48003e62
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6
we must not cause a failure if we cannot write to the log
$ hg rollback
repository tip rolled back to revision 1 (undo pull)
$ mv .hg/blackbox.log .hg/blackbox.log-
$ mkdir .hg/blackbox.log
$ hg --debug incoming
warning: cannot write to blackbox.log: * (glob)
comparing with $TESTTMP/blackboxtest (glob)
query 1; heads
searching for changes
all local heads known remotely
changeset: 2:d02f48003e62c24e2659d97d30f2a83abe5d5d51
tag: tip
phase: draft
parent: 1:6563da9dcf87b1949716e38ff3e3dfaa3198eb06
parent: -1:0000000000000000000000000000000000000000
manifest: 2:ab9d46b053ebf45b7996f2922b9893ff4b63d892
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files+: c
extra: branch=default
description:
c
$ hg pull
pulling from $TESTTMP/blackboxtest (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
a failure reading from the log is fatal
$ hg blackbox -l 3
abort: *$TESTTMP/blackboxtest2/.hg/blackbox.log* (glob)
[255]
$ rmdir .hg/blackbox.log
$ mv .hg/blackbox.log- .hg/blackbox.log
backup bundles get logged
$ touch d
$ hg commit -Amd
adding d
created new head
$ hg strip tip
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/*-backup.hg (glob)
$ hg blackbox -l 6
1970/01/01 00:00:00 bob @73f6ee326b27d820b0472f1a825e3a50f3dc489b (5000)> strip tip
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/73f6ee326b27-7612e004-backup.hg (glob)
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated base branch cache in * seconds (glob)
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote base branch cache with 1 labels and 2 nodes
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> strip tip exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6
extension and python hooks - use the eol extension for a pythonhook
$ echo '[extensions]' >> .hg/hgrc
$ echo 'eol=' >> .hg/hgrc
$ echo '[hooks]' >> .hg/hgrc
$ echo 'update = echo hooked' >> .hg/hgrc
$ hg update
hooked
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 other heads for branch "default"
$ hg blackbox -l 6
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> update
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> writing .hg/cache/tags2-visible with 0 tags
1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pythonhook-preupdate: hgext.eol.preupdate finished in * seconds (glob)
1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> exthook-update: echo hooked finished in * seconds (glob)
1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> update exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> blackbox -l 6
log rotation
$ echo '[blackbox]' >> .hg/hgrc
$ echo 'maxsize = 20 b' >> .hg/hgrc
$ echo 'maxfiles = 3' >> .hg/hgrc
$ hg status
$ hg status
$ hg status
$ hg tip -q
2:d02f48003e62
$ ls .hg/blackbox.log*
.hg/blackbox.log
.hg/blackbox.log.1
.hg/blackbox.log.2
$ cd ..
$ hg init blackboxtest3
$ cd blackboxtest3
$ hg blackbox
1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox
$ mv .hg/blackbox.log .hg/blackbox.log-
$ mkdir .hg/blackbox.log
$ sed -e 's/\(.*test1.*\)/#\1/; s#\(.*commit2.*\)#os.rmdir(".hg/blackbox.log")\
> os.rename(".hg/blackbox.log-", ".hg/blackbox.log")\
> \1#' $TESTDIR/test-dispatch.py > ../test-dispatch.py
$ python $TESTDIR/blackbox-readonly-dispatch.py
running: add foo
result: 0
running: commit -m commit1 -d 2000-01-01 foo
result: None
running: commit -m commit2 -d 2000-01-02 foo
result: None
running: log -r 0
changeset: 0:0e4634943879
user: test
date: Sat Jan 01 00:00:00 2000 +0000
summary: commit1
result: None
running: log -r tip
changeset: 1:45589e459b2e
tag: tip
user: test
date: Sun Jan 02 00:00:00 2000 +0000
summary: commit2
result: None
$ hg blackbox
1970/01/01 00:00:00 bob @0e46349438790c460c5c9f7546bfcd39b267bbd2 (5000)> commit -m commit2 -d 2000-01-02 foo
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> updated served branch cache in * seconds (glob)
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> wrote served branch cache with 1 labels and 1 nodes
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> commit -m commit2 -d 2000-01-02 foo exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r 0
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> writing .hg/cache/tags2-visible with 0 tags
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r 0 exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r tip
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r tip exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> blackbox
Test log recursion from dirty status check
$ cat > ../r.py <<EOF
> from mercurial import context, error, extensions
> x=[False]
> def status(orig, *args, **opts):
> args[0].repo().ui.log("broken", "recursion?")
> return orig(*args, **opts)
> def reposetup(ui, repo):
> extensions.wrapfunction(context.basectx, 'status', status)
> EOF
$ hg id --config extensions.x=../r.py --config blackbox.dirty=True
45589e459b2e tip
cleanup
$ cd ..