f4a8fde057
The match_pathspec_item() function takes "prefix" value, allowing a caller to chop off the common leading prefix of pathspec pattern strings from the path and only use the remainder of the path to match the pathspec patterns (after chopping the same leading prefix of them, of course). This "common leading prefix" optimization has two main features: * discard the entries in the in-core index that are outside of the common leading prefix; if you are doing "ls-files one/a one/b", we know all matches must be from "one/", so first the code discards all entries outside the "one/" directory from the in-core index. This allows us to work on a smaller dataset. * allow skipping the comparison of the leading bytes when matching pathspec with path. When "ls-files" finds the path "one/a/1" in the in-core index given "one/a" and "one/b" as the pathspec, knowing that common leading prefix "one/" was found lets the pathspec matchinery not to bother comparing "one/" part, and allows it to feed "a/1" down, as long as the pathspec element "one/a" gets corresponding adjustment to "a". When the "attr" pathspec magic is in effect, however, the current code breaks down. The attributes, other than the ones that are built-in and the ones that come from the $GIT_DIR/info/attributes file and the top-level .gitattributes file, are lazily read from the filesystem on-demand, as we encounter each path and ask if it matches the pathspec. For example, if you say "git ls-files "(attr:label)sub/" in a repository with a file "sub/file" that is given the 'label' attribute in "sub/.gitattributes": * The common prefix optimization finds that "sub/" is the common prefix and prunes the in-core index so that it has only entries inside that directory. This is desirable. * The code then walks the in-core index, finds "sub/file", and eventually asks do_match_pathspec() if it matches the given pathspec. * do_match_pathspec() calls match_pathspec_item() _after_ stripping the common prefix "sub/" from the path, giving it "file", plus the length of the common prefix (4-bytes), so that the pathspec element "(attr:label)sub/" can be treated as if it were "(attr:label)". The last one is what breaks the match in the current code, as the pathspec subsystem ends up asking the attribute subsystem to find the attribute attached to the path "file". We need to ask about the attributes on "sub/file" when calling match_pathspec_attrs(); this can be done by looking at "prefix" bytes before the beginning of "name", which is the same trick already used by another piece of the code in the same match_pathspec_item() function. Unfortunately this was not discovered so far because the code works with slightly different arguments, e.g. $ git ls-files "(attr:label)sub" $ git ls-files "(attr:label)sub/" "no/such/dir/" would have reported "sub/file" as a path with the 'label' attribute just fine, because neither would trigger the common prefix optimization. Reported-by: Matthew Hughes <mhughes@uw.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org (not the Git list). The mailing list archives are available at https://lore.kernel.org/git/, http://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks