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:

  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:

  out-of-range roots are ignored:

  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