tests/test-parseindex.t

revset: add "matching" keyword

This keyword can be used to find revisions that "match" one or more fields of a
given set of revisions.

A revision matches another if all the selected fields (description, author,
branch, date, files, phase, parents, substate, user, summary and/or metadata)
match the corresponding values of those fields on the source revision.

By default this keyword looks for revisions that whose metadata match
(description, author and date) making it ideal to look for duplicate revisions.

matching takes 2 arguments (the second being optional):

1.- rev: a revset represeting a _single_ revision (e.g. tip, ., p1(.), etc)
2.- [field(s) to match]: an optional string containing the field or fields
(separated by spaces) to match.
    Valid fields are most regular context fields and some special fields:
    * regular fields:
      - description, author, branch, date, files, phase, parents,
      substate, user.
      Note that author and user are synonyms.
    * special fields: summary, metadata.
      - summary: matches the first line of the description.
      - metatadata: It is equivalent to matching 'description user date'
        (i.e. it matches the main metadata fields).

Examples:

1.- Look for revisions with the same metadata (author, description and date)
as the 11th revision:

hg log -r "matching(11)"

2.- Look for revisions with the same description as the 11th revision:

hg log -r "matching(11, description)"

3.- Look for revisions with the same 'summary' (i.e. same first line on their
description) as the 11th revision:

hg log -r "matching(11, summary)"

4.- Look for revisions with the same author as the current revision:

hg log -r "matching(., author)"

You could use 'user' rather than 'author' to get the same result.

5.- Look for revisions with the same description _AND_ author as the tip of the
repository:

hg log -r "matching(tip, 'author description')"

6.- Look for revisions touching the same files as the parent of the tip of the
repository

hg log -r "matching(p1(tip), files)"

7.- Look for revisions whose subrepos are on the same state as the tip of the
repository or its parent

hg log -r "matching(p1(tip):tip, substate)"

8.- Look for revisions whose author and subrepo states both match those of any
of the revisions on the stable branch:

hg log -r "matching(branch(stable), 'author substate')"

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