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view tests/test-tools.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outdated and unsupported repo format.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 | 6686ae524f94 |
children | 75be14993fda |
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Tests of the file helper tool $ f -h ?sage: f [options] [filenames] (glob) ?ptions: (glob) -h, --help show this help message and exit -t, --type show file type (file or directory) -m, --mode show file mode -l, --links show number of links -s, --size show size of file -n NEWER, --newer=NEWER check if file is newer (or same) -r, --recurse recurse into directories -S, --sha1 show sha1 hash of the content -M, --md5 show md5 hash of the content -D, --dump dump file content -H, --hexdump hexdump file content -B BYTES, --bytes=BYTES number of characters to dump -L LINES, --lines=LINES number of lines to dump -q, --quiet no default output $ mkdir dir $ cd dir $ f --size size=0 $ echo hello | f --md5 --size size=6, md5=b1946ac92492d2347c6235b4d2611184 $ f foo foo: file not found $ echo foo > foo $ f foo foo: #if symlink $ f foo --mode foo: mode=644 #endif #if no-windows $ python $TESTDIR/seq.py 10 > bar #else Convert CRLF -> LF for consistency $ python $TESTDIR/seq.py 10 | sed "s/$//" > bar #endif #if unix-permissions symlink $ chmod +x bar $ f bar --newer foo --mode --type --size --dump --links --bytes 7 bar: file, size=21, mode=755, links=1, newer than foo >>> 1 2 3 4 <<< no trailing newline #endif #if unix-permissions $ ln bar baz $ f bar -n baz -l --hexdump -t --sha1 --lines=9 -B 20 bar: file, links=2, newer than baz, sha1=612ca68d0305c821750a 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 0a |9.| $ rm baz #endif #if unix-permissions symlink $ ln -s yadda l $ f . --recurse -MStmsB4 .: directory with 3 files, mode=755 ./bar: file, size=21, mode=755, md5=3b03, sha1=612c ./foo: file, size=4, mode=644, md5=d3b0, sha1=f1d2 ./l: link, size=5, md5=2faa, sha1=af93 #endif $ f --quiet bar -DL 3 1 2 3 $ cd .. Yadda is a symlink #if symlink $ f -qr dir -HB 17 dir: directory with 3 files dir/bar: 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 |9| dir/foo: 0000: 66 6f 6f 0a |foo.| dir/l: 0000: 79 61 64 64 61 |yadda| #else $ f -qr dir -HB 17 dir: directory with 2 files (esc) dir/bar: (glob) 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 |9| dir/foo: (glob) 0000: 66 6f 6f 0a |foo.| #endif