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
run-tests: outputdir also has to be changed if $TESTDIR is not $PWD
Following
a18eef03d879, running run-tests.py from outside tests/ would lead to
the creation of .testtimes and test-*.t.err in $PWD instead of $TESTDIR. This
patch fixes that and updates the relevant test.
hgweb: use webutil.commonentry() for nodes (but not for jsdata yet) in /graph
This makes graphdata() simpler by using existing code that gets common
changeset properties for showing in hgweb. graphdata() is a nested function in
graph() that prepares entries for /graph view, but there are two different
lists of changesets prepared: "jsdata" for JavaScript-rendered graph and
"nodes" for everything else.
For "jsdata", properties "node", "user", "age" and "desc" are passed through
various template filters because we don't have these filters in JavaScript, so
the data has to be prepared server-side. But now that commonentry() is used for
producing "nodes" list (and it doesn't apply any filters), these filters need
to be added to the appropriate templates (only raw at this moment, everything
else either doesn't implement graph or uses JavaScript).
This is a bit of refactoring that will hopefully simplify future patches. The
end result is to have /graph that only renders the actual graph with nodes and
vertices in JavaScript, and the rest is done server-side. This way server-side
code can focus on showing a list of changesets, which is easy because we
already have /log, /shortlog, etc, and JavaScript code can be simplified,
making it easier to add obsolescence graph and other features.
hgweb: check changeset's original branch in graphdata()
This piece of code checks if a changeset is the tip of its branch, but as can
be seen above in the context, "branch" was prepared for being displayed in
hgweb by making it unicode and passing it through url.escape. It's better to
use the original ctx.branch().
hgweb: show instabilities of a commit
In paper, coal, gitweb and monoblue a new "tag" (or multiple, if there are many
instabilities) is added to the same line that has phase, branch, etc of a
changeset; in gitweb and monoblue this element has a light red background, in
paper and coal the element is black and underlined. In spartan theme
instabilities are shown on a separate line.
While test-obsolete.t uses first(phasedivergent()) revset to pick a changeset
to test, that particular changeset is also an orphan, so two different
instability tags are displayed.
context: add instabilities() method to basefilectx
This method is now used in webutils.commonentry(), which adds common data items
(commit hash, author, date, etc) for rendering changesets in hgweb. Usually,
commonentry() is given a changectx as ctx; but in views related to files (e.g.
file view, diff, annotate) it's replaced by a filectx, so the latter also needs
to have instabilities() method.