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The existing reachability algorithms in commit-reach.c focus on finding merge-bases or determining if all commits in a set X can reach at least one commit in a set Y. However, for two commits sets X and Y, we may also care about which commits in Y are reachable from at least one commit in X. Implement get_reachable_subset() which answers this question. Given two arrays of commits, 'from' and 'to', return a commit_list with every commit from the 'to' array that is reachable from at least one commit in the 'from' array. The algorithm is a simple walk starting at the 'from' commits, using the PARENT2 flag to indicate "this commit has already been added to the walk queue". By marking the 'to' commits with the PARENT1 flag, we can determine when we see a commit from the 'to' array. We remove the PARENT1 flag as we add that commit to the result list to avoid duplicates. The order of the resulting list is a reverse of the order that the commits are discovered in the walk. There are a couple shortcuts to avoid walking more than we need: 1. We determine the minimum generation number of commits in the 'to' array. We do not walk commits with generation number below this minimum. 2. We count how many distinct commits are in the 'to' array, and decrement this count when we discover a 'to' commit during the walk. If this number reaches zero, then we can terminate the walk. Tests will be added using the 'test-tool reach' helper in a subsequent commit. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> 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-.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). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.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