exchange: make clone bundles non-experimental and enabled by default
The clone bundles feature was introduced in Mercurial 3.6 behind an
experimental and disabled by default flag. The feature has been enabled
on hg.mozilla.org for a few months and has served many terabytes of
clones. Users have been encouraged to use the feature and reception
has been very positive (mainly due to faster clones as a result of
connecting to a CDN). I have heard no feedback about changing the
feature other than inquiries about when it will be enabled by default.
So, I think the feature is ready to be enabled by default.
This patch renames experimental.clonebundles to ui.clonebundles,
documents the option, and enables it by default. References to the
experimental state of clone bundles have been removed. The remaining
config option docs in clonebundles.py have been removed because they
are redudant with `hg help config`.
There are some oddities with behavior of clone bundles. Because clones
with clone bundles are effectively 2 `hg pull` operations, there may be
2 transactions. This could result in hooks running twice. If the
subsequent pull is aborted, it could result in partial rollback and an
incomplete clone. This behavior is a bit wonky and should probably
be documented. If this patch is accepted, I'll send a follow-up to
document it. I don't think this behavior should prevent the feature
being enabled by default. Reworking the clone mechanism to support
interrupted or multi-part clones feels like a major new feature and
something that when implemented can change the hook and rollback
semantics of clone bundles. Besides, partial clone is better than
full rollback and hooks running on initial clone are likely rare, so I
think the impact is minimal.
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, scmutil
> 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 = scmutil.opener(*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, scmutil
> cl = changelog.changelog(scmutil.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, scmutil
> cl = changelog.changelog(scmutil.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