Mercurial > hg
view tests/test-flags.t @ 32697:19b9fc40cc51
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outdated and unsupported repo format.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.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 19 May 2017 20:29:11 -0700 |
parents | 7a9cbb315d84 |
children | eb586ed5d8ce |
line wrap: on
line source
#require execbit $ umask 027 $ hg init test1 $ cd test1 $ touch a b $ hg add a b $ hg ci -m "added a b" $ cd .. $ hg clone test1 test3 updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg init test2 $ cd test2 $ hg pull ../test1 pulling from ../test1 requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 2 changes to 2 files (run 'hg update' to get a working copy) $ hg co 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ chmod +x a $ hg ci -m "chmod +x a" the changelog should mention file a: $ hg tip --template '{files}\n' a $ cd ../test1 $ echo 123 >>a $ hg ci -m "a updated" $ hg pull ../test2 pulling from ../test2 searching for changes adding changesets adding manifests adding file changes added 1 changesets with 0 changes to 0 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg heads changeset: 2:7f4313b42a34 tag: tip parent: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: chmod +x a changeset: 1:c6ecefc45368 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a updated $ hg history changeset: 2:7f4313b42a34 tag: tip parent: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: chmod +x a changeset: 1:c6ecefc45368 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a updated changeset: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: added a b $ hg -v merge resolving manifests 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ cat a 123 $ [ -x a ] $ cd ../test3 $ echo 123 >>b $ hg ci -m "b updated" $ hg pull ../test2 pulling from ../test2 searching for changes adding changesets adding manifests adding file changes added 1 changesets with 0 changes to 0 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg heads changeset: 2:7f4313b42a34 tag: tip parent: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: chmod +x a changeset: 1:dc57ead75f79 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b updated $ hg history changeset: 2:7f4313b42a34 tag: tip parent: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: chmod +x a changeset: 1:dc57ead75f79 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b updated changeset: 0:22a449e20da5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: added a b $ hg -v merge resolving manifests 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ ls -l ../test[123]/a > foo $ cut -b 1-10 < foo -rwxr-x--- -rwxr-x--- -rwxr-x--- $ hg debugindex a rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re) $ hg debugindex -R ../test2 a rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re) $ hg debugindex -R ../test1 a rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re) 1 0 5 ..... 1 7fe919cc0336 b80de5d13875 000000000000 (re) $ cd ..