Working Directory State
Mercurial tracks various information about the [:WorkingDirectory:working directory] (the dirstate):
- what revision(s) are currently checked out
- what files have been copied or renamed
- what files are controlled by Mercurial
For each file that Mercurial controls, we record the following information:
- its size
- its mode
- its modification time
- its "state"
The states that are tracked are:
- n - normal
- a - added
- r - removed
- m - 3-way merged
With this information, we can quickly determine what files in the working directory have changed.
Here's an example of the dirstate:
$ hg parents -q 1224:cc61d366bc3b $ hg debugstate n 644 168 08/19/05 17:42:17 .hgignore n 644 412 08/20/05 01:46:57 .hgtags n 644 1328 08/26/05 23:22:20 CONTRIBUTORS n 644 17992 06/30/05 10:19:51 COPYING n 644 459 08/24/05 00:38:20 MANIFEST.in n 644 512 08/24/05 00:35:02 Makefile n 644 232 06/30/05 10:19:51 PKG-INFO n 644 2736 08/20/05 00:48:33 README n 644 1676 06/30/05 10:19:51 comparison.txt n 644 3711 12/31/69 15:59:59 contrib/bash_completion n 711 1305 07/01/05 15:04:52 contrib/buildrpm n 755 8300 08/16/05 16:03:59 contrib/convert-repo n 644 69 06/30/05 10:19:51 contrib/git-viz/git-cat-file n 644 69 06/30/05 10:19:51 contrib/git-viz/git-diff-tree n 644 69 06/30/05 10:19:51 contrib/git-viz/git-rev-list n 644 69 06/30/05 10:19:51 contrib/git-viz/git-rev-tree n 644 457 06/30/05 10:19:51 contrib/git-viz/hg-viz n 755 8039 08/16/05 16:03:59 contrib/hgit n 755 40043 06/30/05 10:19:51 contrib/hgk ...
For files having state "n" in the dirstate, Mercurial compares the file modification time and the size in the dirstate with the modification time and the size of the file in the working directory. If both the modification time and the size are the same, Mercurial will not include it in the next [:Commit:commit].
See also [http://www.selenic.com/hg/rev/af3f26b6bba4 dirstate: ignore stat data for files that were updated too recently], changeset af3f26b6bba4 by Alexis S. L. Carvalho (introduced in Mercurial release 1.0); and an explanation given by Matt Mackall in http://selenic.com/pipermail/mercurial/2008-August/020984.html for this.