annotate tests/test-parseindex.t @ 37048:fc5e261915b9

wireproto: require POST for all HTTPv2 requests

Wire protocol version 1 transfers argument data via request
headers by default. This has historically caused problems because
servers institute limits on the length of individual HTTP headers
as well as the total size of all request headers. Mercurial servers
can advertise the maximum length of an individual header. But
there's no guarantee any intermediate HTTP agents will accept
headers up to that length.

In the existing wire protocol, server operators typically also
key off the HTTP request method to implement authentication.
For example, GET requests translate to read-only requests and
can be allowed. But read-write commands must use POST and require
authentication. This has typically worked because the only wire
protocol commands that use POST modify the repo (e.g. the
"unbundle" command).

There is an experimental feature to enable clients to transmit
argument data via POST request bodies. This is technically a
better and more robust solution. But we can't enable it by default
because of servers assuming POST means write access.

In version 2 of the wire protocol, the permissions of a request
are encoded in the URL. And with it being a new protocol in a new
URL space, we're not constrained by backwards compatibility
requirements.

This commit adopts the technically superior mechanism of using
HTTP request bodies to send argument data by requiring POST for
all commands. Strictly speaking, it may be possible to send
request bodies on GET requests. But my experience is that not all
HTTP stacks support this. POST pretty much always works. Using POST
for read-only operations does sacrifice some RESTful design
purity. But this API cares about practicality, not about being
in Roy T. Fielding's REST ivory tower.

There's a chance we may relax this restriction in the future. But
for now, I want to see how far we can get with a POST only API.

Differential Revision: https://phab.mercurial-scm.org/D2837

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 __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)
  >     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