view tests/test-parseindex.t @ 23972:c408bf3b32f8 stable

convert: replace revision references in messages if they are >= short hashes

Convert will try to find references to revisions in commit messages and replace
them with references to the converted revision. It will take any string that
looks like a hash (and thus also decimal numbers) and look it up in the source
repo. If it finds anything, it will use that in the commit message instead.

It would do that for all hex digit sequences of 6 to 40 characters. That was
usually no problem for small repos where it was unlikely that there would be a
matching 6 'digit' hash prefix. It was also no problem on repos with less than
100000 changesets where numbers with 6 or more digits not would match any
revision number. With more than 100000 revisions random numbers in commit
messages would be replaced with a "random" hash. For example, 'handle 100000
requests' would be changed to to 'handle 9117c6 requests'. Convert could thus
not really be used on real repositories with more than 100000 changesets.

The default hash length shown by Mercurial is 12 'digits'. It is unexpected and
unwanted that convert by default tries to replace revision references that use
less than that amount of 'digits'.

To fix this, don't match strings that are less than the default hash size of 12
characters.

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 ..