changelog: never inline changelog
The test suite mostly use small repositories, that implies that most changelog in the
tests are inlined. As a result, non-inlined changelog are quite poorly tested.
Since non-inline changelog are most common case for serious repositories, this
lack of testing is a significant problem that results in high profile issue like
the one recently fixed by
66417f55ea33 and
849745d7da89.
Inlining the changelog does not bring much to the table, the number of total
file saved is negligible, and the changelog will be read by most operation
anyway.
So this changeset is make it so we never inline the changelog, and de-inline the
one that are still inlined whenever we touch them.
By doing that, we remove the "dual code path" situation for writing new entry to
the changelog and move to a "single code path" situation. Having a single
code path simplify the code and make sure it is covered by test (if test cover
that situation obviously)
This impact all tests that care about the number of file and the exchange size,
but there is nothing too complicated in them just a lot of churn.
The churn is made "worse" by the fact rust will use the persistent nodemap on
any changelog now. Which is overall a win as it means testing the persistent
nodemap more and having less special cases.
In short, having inline changelog is mostly useless and an endless source of
pain. We get rid of it.
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, node, pycompat, vfs
>
> 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 __enter__(self):
> self.real.__enter__()
> return self
>
> def __exit__(self, *args, **kwargs):
> return self.real.__exit__(*args, **kwargs)
>
> def opener(*args):
> o = vfs.vfs(*args)
> def wrapper(*a, **kwargs):
> f = o(*a, **kwargs)
> return singlebyteread(f)
> wrapper.options = o.options
> return wrapper
>
> cl = changelog.changelog(opener(b'.hg/store'))
> print(len(cl), 'revisions:')
> for r in cl:
> print(pycompat.sysstr(node.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(b'.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, end=' ')
> 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, end=' ')
> 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( .got type NoneType.)?|'NoneType' object cannot be interpreted as an integer) (re)
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( .got type NoneType.)?|'NoneType' object cannot be interpreted as an integer) (re)
$ 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 --config format.sparse-revlog=no
$ hg clone --pull -q --config phases.publish=False ../a neglimit --config format.sparse-revlog=no
$ hg clone --pull -q --config phases.publish=False ../a segv --config format.sparse-revlog=no
$ rm -R limit/.hg/cache neglimit/.hg/cache segv/.hg/cache
$ "$PYTHON" <<EOF
> data = open("limit/.hg/store/00changelog.i", "rb").read()
> poisons = [
> (b'limit', b'\0\0\0\x02'),
> (b'neglimit', b'\xff\xff\xff\xfe'),
> (b'segv', b'\0\x01\0\0'),
> ]
> for n, p in poisons:
> # corrupt p1 at rev0 and p2 at rev1
> rev_0 = data[:64]
> rev_1 = data[64:]
> altered_rev_0 = rev_0[:24] + p + rev_0[24 + 4:]
> altered_rev_1 = rev_1[:28] + p + rev_1[28 + 4:]
> new_data = altered_rev_0 + altered_rev_1
> with open(n + b"/.hg/store/00changelog.i", "wb") as f:
> f.write(new_data)
> EOF
$ hg -R limit debugrevlogindex -f1 -c
rev flag size link p1 p2 nodeid
0 0000 62 0 2 -1 7c31755bf9b5
1 0000 65 1 0 2 26333235a41c
$ hg -R limit debugdeltachain -c
rev p1 p2 chain# chainlen prev delta
0 2 -1 1 1 -1 base
1 0 2 2 1 -1 base
$ hg -R neglimit debugrevlogindex -f1 -c
rev flag size link p1 p2 nodeid
0 0000 62 0 -2 -1 7c31755bf9b5
1 0000 65 1 0 -2 26333235a41c
$ hg -R segv debugrevlogindex -f1 -c
rev flag size link p1 p2 nodeid
0 0000 62 0 65536 -1 7c31755bf9b5
1 0000 65 1 0 65536 26333235a41c
$ hg -R segv debugdeltachain -c
rev p1 p2 chain# chainlen prev delta
0 65536 -1 1 1 -1 base
1 0 65536 2 1 -1 base
$ cat <<EOF > test.py
> import sys
> from mercurial import changelog, pycompat, vfs
> cl = changelog.changelog(vfs.vfs(pycompat.fsencode(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({1: {cl.node(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 + ':', end=' ')
> try:
> f()
> print('uncaught buffer overflow?')
> except ValueError as 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 neglimit/.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