Mercurial > hg
view tests/test-parseindex.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 | 8e6f4939a69a |
children | c839bbee1e13 |
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revlog.parseindex must be able to parse the index file even if an index entry is split between two 64k blocks. The ideal test would be to create an index file with inline data where 64k < size < 64k + 64 (64k is the size of the read buffer, 64 is the size of an index entry) and with an index entry starting right before the 64k block boundary, and try to read it. We approximate that by reducing the read buffer to 1 byte. $ hg init a $ cd a $ echo abc > foo $ hg add foo $ hg commit -m 'add foo' $ echo >> foo $ hg commit -m 'change foo' $ hg log -r 0: changeset: 0:7c31755bf9b5 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo changeset: 1:26333235a41c tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: change foo $ cat >> test.py << EOF > from mercurial import changelog, vfs > from mercurial.node import * > > class singlebyteread(object): > def __init__(self, real): > self.real = real > > def read(self, size=-1): > if size == 65536: > size = 1 > return self.real.read(size) > > def __getattr__(self, key): > return getattr(self.real, key) > > def opener(*args): > o = vfs.vfs(*args) > def wrapper(*a): > f = o(*a) > return singlebyteread(f) > return wrapper > > cl = changelog.changelog(opener('.hg/store')) > print len(cl), 'revisions:' > for r in cl: > print short(cl.node(r)) > EOF $ $PYTHON test.py 2 revisions: 7c31755bf9b5 26333235a41c $ cd .. #if no-pure Test SEGV caused by bad revision passed to reachableroots() (issue4775): $ cd a $ $PYTHON <<EOF > from mercurial import changelog, vfs > cl = changelog.changelog(vfs.vfs('.hg/store')) > print 'good heads:' > for head in [0, len(cl) - 1, -1]: > print'%s: %r' % (head, cl.reachableroots(0, [head], [0])) > print 'bad heads:' > for head in [len(cl), 10000, -2, -10000, None]: > print '%s:' % head, > try: > cl.reachableroots(0, [head], [0]) > print 'uncaught buffer overflow?' > except (IndexError, TypeError) as inst: > print inst > print 'good roots:' > for root in [0, len(cl) - 1, -1]: > print '%s: %r' % (root, cl.reachableroots(root, [len(cl) - 1], [root])) > print 'out-of-range roots are ignored:' > for root in [len(cl), 10000, -2, -10000]: > print '%s: %r' % (root, cl.reachableroots(root, [len(cl) - 1], [root])) > print 'bad roots:' > for root in [None]: > print '%s:' % root, > try: > cl.reachableroots(root, [len(cl) - 1], [root]) > print 'uncaught error?' > except TypeError as inst: > print inst > EOF good heads: 0: [0] 1: [0] -1: [] bad heads: 2: head out of range 10000: head out of range -2: head out of range -10000: head out of range None: an integer is required good roots: 0: [0] 1: [1] -1: [-1] out-of-range roots are ignored: 2: [] 10000: [] -2: [] -10000: [] bad roots: None: an integer is required $ cd .. Test corrupted p1/p2 fields that could cause SEGV at parsers.c: $ mkdir invalidparent $ cd invalidparent $ hg clone --pull -q --config phases.publish=False ../a limit $ hg clone --pull -q --config phases.publish=False ../a segv $ rm -R limit/.hg/cache segv/.hg/cache $ $PYTHON <<EOF > data = open("limit/.hg/store/00changelog.i", "rb").read() > for n, p in [('limit', '\0\0\0\x02'), ('segv', '\0\x01\0\0')]: > # corrupt p1 at rev0 and p2 at rev1 > d = data[:24] + p + data[28:127 + 28] + p + data[127 + 32:] > open(n + "/.hg/store/00changelog.i", "wb").write(d) > EOF $ hg debugindex -f1 limit/.hg/store/00changelog.i rev flag offset length size base link p1 p2 nodeid 0 0000 0 63 62 0 0 2 -1 7c31755bf9b5 1 0000 63 66 65 1 1 0 2 26333235a41c $ hg debugindex -f1 segv/.hg/store/00changelog.i rev flag offset length size base link p1 p2 nodeid 0 0000 0 63 62 0 0 65536 -1 7c31755bf9b5 1 0000 63 66 65 1 1 0 65536 26333235a41c $ cat <<EOF > test.py > import sys > from mercurial import changelog, vfs > cl = changelog.changelog(vfs.vfs(sys.argv[1])) > n0, n1 = cl.node(0), cl.node(1) > ops = [ > ('reachableroots', > lambda: cl.index.reachableroots2(0, [1], [0], False)), > ('compute_phases_map_sets', lambda: cl.computephases([[0], []])), > ('index_headrevs', lambda: cl.headrevs()), > ('find_gca_candidates', lambda: cl.commonancestorsheads(n0, n1)), > ('find_deepest', lambda: cl.ancestor(n0, n1)), > ] > for l, f in ops: > print l + ':', > try: > f() > print 'uncaught buffer overflow?' > except ValueError, inst: > print inst > EOF $ $PYTHON test.py limit/.hg/store reachableroots: parent out of range compute_phases_map_sets: parent out of range index_headrevs: parent out of range find_gca_candidates: parent out of range find_deepest: parent out of range $ $PYTHON test.py segv/.hg/store reachableroots: parent out of range compute_phases_map_sets: parent out of range index_headrevs: parent out of range find_gca_candidates: parent out of range find_deepest: parent out of range $ cd .. #endif