Mercurial > hg
view tests/test-convert-darcs.t @ 35098:66c5a8cf2868
lfs: import the Facebook git-lfs client extension
The purpose of this is the same as the built-in largefiles extension- to handle
huge files outside of the normal storage system, generally to keep the amount of
data cloned to a lower amount. There are several benefits of implementing the
git-lfs protocol, instead of using the largefiles extension:
- Bitbucket and Github support (and probably wider support in 3rd party
hosting sites in general). [1][2]
- The number of hg internals monkey patched are several orders of magnitude
lower, so it will be easier to reason about and maintain. Future commands
will likely just work, without requiring various wrappers.
- The "standin" files are only written to the filelog, not the disk. That
should avoid weird edge cases where the largefile and standin files get out
of sync. [3] It also avoids the occasional printing of the "hidden" standin
file in various messages.
- Filesets like size() will work, even if the file isn't present. (It always
says 41 bytes for largefiles, whether present or not.)
The only place that I see where largefiles comes out on top is that it works
with `hg serve` for simple sharing, without external infrastructure. Getting
lfs-test-server working was a hassle, and took awhile to figure out. Maybe we
can do something to make it work in the future.
Long term, I expect that this will be highly preferred over largefiles. But if
we are to recommend this to largefile users, there are some UI issues to
bikeshed. Until they are resolved, I've marked this experimental, and am not
putting a pointer to this in the largefiles help. The (non exhaustive) list of
issues I've seen so far are:
- It isn't sufficient to just enable the largefiles extension- you have to
explicitly add a file with --large before it will pay attention to the
configured sizes and patterns on future adds. The justification being that
once you use it, you're stuck with it. I've seen people confused by this,
and haven't liked it myself. But it's also saved me a few times. Should we
do something like have a specific enabling config setting that must be set
in the local repo config, so that enabling this extension in the user or
system hgrc doesn't silently start storing lfs files?
- The largefiles extension adds a repo requirement when the first largefile is
committed, so that the extension must always be enabled in the future. This
extension is not doing that, and since I only enabled it locally to avoid
infecting other repos, I got a cryptic error about missing flag processors
when I cloned. Is there no repo requirement due to shallow/narrow clone
considerations (or other future advanced things)?
- In the (small amount of) reading I've done about the git implementation, it
seems that the files and sizes are stored in a tracked .gitattributes file.
I think a tracked file for this would be extremely useful for consistency
across developers, but this kind of touches on the tracked hgrc file
proposal a few months back.
- The git client can specify file patterns, not just sizes.
- The largefiles extension has a cache directory in the local repo, but also a
system wide one. We should probably implement a system wide cache too, so
that multiple clones don't have to refetch the files from the server.
- Jun mentioned other missing features, like SSH authentication, gc, etc.
The code corresponds to c0492b73c7ef in hg-experimental. [4] The only tweaks
are to load the extension in the tests with 'lfs=' instead of
'lfs=$TESTDIR/../hgext3rd/lfs', change the import in the *.py test to hgext
(from hgext3rd), add the 'testedwith' declaration, and mark it experimental for
now. The infinite-push, p4fastimport, and remotefilelog tests were left behind.
The devel-warnings for unregistered config options are not corrected yet, nor
are the import check warnings.
[1] https://www.mercurial-scm.org/pipermail/mercurial/2017-November/050699.html
[2] https://bitbucket.org/site/master/issues/3843/largefiles-support-bb-3903
[3] https://bz.mercurial-scm.org/show_bug.cgi?id=5738
[4] https://bitbucket.org/facebook/hg-experimental
author | Matt Harbison <matt_harbison@yahoo.com> |
---|---|
date | Tue, 14 Nov 2017 00:06:23 -0500 |
parents | ab929a174f7b |
children |
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#require darcs $ echo "[extensions]" >> $HGRCPATH $ echo "convert=" >> $HGRCPATH $ DARCS_EMAIL='test@example.org'; export DARCS_EMAIL initialize darcs repo $ mkdir darcs-repo $ cd darcs-repo $ darcs init -q $ echo a > a $ darcs record -a -l -m p0 Finished recording patch 'p0' $ cd .. branch and update $ darcs get -q darcs-repo darcs-clone >/dev/null $ cd darcs-clone $ echo c >> a $ echo c > c $ darcs record -a -l -m p1.1 Finished recording patch 'p1.1' $ cd .. skip if we can't import elementtree $ if hg convert darcs-repo darcs-dummy 2>&1 | grep ElementTree > /dev/null; then > echo 'skipped: missing feature: elementtree module' > exit 80 > fi update source $ cd darcs-repo $ echo b >> a $ echo b > b $ darcs record -a -l -m p1.2 Finished recording patch 'p1.2' $ darcs pull -q -a --no-set-default ../darcs-clone Backing up ./a(*) (glob) We have conflicts in the following files: ./a (?) $ sleep 1 $ echo e > a $ echo f > f $ mkdir dir $ echo d > dir/d $ echo d > dir/d2 $ darcs record -a -l -m p2 Finished recording patch 'p2' test file and directory move $ darcs mv -q f ff Test remove + move $ darcs remove -q dir/d2 $ rm dir/d2 $ darcs mv -q dir dir2 $ darcs record -a -l -m p3 Finished recording patch 'p3' The converter does not currently handle patch conflicts very well. When they occur, it reverts *all* changes and moves forward, letting the conflict resolving patch fix collisions. Unfortunately, non-conflicting changes, like the addition of the "c" file in p1.1 patch are reverted too. Just to say that manifest not listing "c" here is a bug. $ cd .. $ hg convert darcs-repo darcs-repo-hg initializing destination darcs-repo-hg repository scanning source... sorting... converting... 4 p0 3 p1.2 2 p1.1 1 p2 0 p3 $ hg log -R darcs-repo-hg -g --template '{rev} "{desc|firstline}" ({author}) files: {files}\n' "$@" 4 "p3" (test@example.org) files: dir/d dir/d2 dir2/d f ff 3 "p2" (test@example.org) files: a dir/d dir/d2 f 2 "p1.1" (test@example.org) files: 1 "p1.2" (test@example.org) files: a b 0 "p0" (test@example.org) files: a $ hg up -q -R darcs-repo-hg $ hg -R darcs-repo-hg manifest --debug 7225b30cdf38257d5cc7780772c051b6f33e6d6b 644 a 1e88685f5ddec574a34c70af492f95b6debc8741 644 b 37406831adc447ec2385014019599dfec953c806 644 dir2/d b783a337463792a5c7d548ad85a7d3253c16ba8c 644 ff #if no-outer-repo try converting darcs1 repository $ hg clone -q "$TESTDIR/bundles/darcs1.hg" darcs $ hg convert -s darcs darcs/darcs1 2>&1 | grep darcs-1.0 darcs-1.0 repository format is unsupported, please upgrade #endif