tests/test-revlog.t

help: show help for disabled extensions (issue5228)

This patch does not exactly solve issue5228 but it results in a better
condition on this issue. For disabled extensions, we used to parse the
module and get the first occurrences of docstring and then return the first
line of that as an introductory heading of extension. This is what we get
today.

This patch returns the whole docstring of the module as a help for extension,
which is more informative. There are some modules which don't have much
docstring at top level except the heading so those are unaffected by this
change. To follow the existing trend of showing commands either we have to
load the extension or have a very ugly parsing method which don't even assure
correctness.

Test for CVE-2016-3630

  $ hg init

  >>> open("a.i", "w").write(
  ... """eJxjYGZgZIAAYQYGxhgom+k/FMx8YKx9ZUaKSOyqo4cnuKb8mbqHV5cBCVTMWb1Cwqkhe4Gsg9AD
  ... Joa3dYtcYYYBAQ8Qr4OqZAYRICPTSr5WKd/42rV36d+8/VmrNpv7NP1jQAXrQE4BqQUARngwVA=="""
  ... .decode("base64").decode("zlib"))

  $ hg debugindex a.i
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      19     -1       2 99e0332bd498 000000000000 000000000000
       1        19      12      0       3 6674f57a23d8 99e0332bd498 000000000000
  $ hg debugdata a.i 1 2>&1 | egrep 'Error:.*decoded'
  (mercurial.mpatch.)?mpatchError: patch cannot be decoded (re)