commit | 02471e7e205c3e6c80f7908877640c0eed526fda | [log] [tgz] |
---|---|---|
author | Johannes Schindelin <johannes.schindelin@gmx.de> | Sat May 09 19:23:39 2020 +0000 |
committer | Junio C Hamano <gitster@pobox.com> | Sat May 09 13:59:55 2020 -0700 |
tree | b8d26e7a1c9b54a1d61bc1a44f634e09dcce2f25 | |
parent | f2a04904be6584f1ec783ed5d3c425026bcf908f [diff] |
rebase --autosquash: fix a potential segfault When rearranging the todo list so that the fixups/squashes are reordered just after the commits they intend to fix up, we use two arrays to maintain that list: `next` and `tail`. The idea is that `next[i]`, if set to a non-negative value, contains the index of the item that should be rearranged just after the `i`th item. To avoid having to walk the entire `next` chain when appending another fixup/squash, we also store the end of the `next` chain in `tail[i]`. The logic we currently use to update these array items is based on the assumption that given a fixup/squash item at index `i`, we just found the index `i2` indicating the first item in that fixup chain. However, as reported by Paul Ganssle, that need not be true: the special form `fixup! <commit-hash>` is allowed to point to _another_ fixup commit in the middle of the fixup chain. Example: * 0192a To fixup * 02f12 fixup! To fixup * 03763 fixup! To fixup * 04ecb fixup! 02f12 Note how the fourth commit targets the second commit, which is already a fixup that targets the first commit. Previously, we would update `next` and `tail` under our assumption that every `fixup!` commit would find the start of the `fixup!`/`squash!` chain. This would lead to a segmentation fault because we would actually end up with a `next[i]` pointing to a `fixup!` but the corresponding `tail[i]` pointing nowhere, which would the lead to a segmentation fault. Let's fix this by _inserting_, rather than _appending_, the item. In other words, if we make a given line successor of another line, we do not simply forget any previously set successor of the latter, but make it a successor of the former. In the above example, at the point when we insert 04ecb just after 02f12, 03763 would already be recorded as a successor of 04ecb, and we now "squeeze in" 04ecb. To complete the idea, we now no longer assume that `next[i]` pointing to a line means that `last[i]` points to a line, too. Instead, we extend the concept of `last` to cover also partial `fixup!`/`squash!` chains, i.e. chains starting in the middle of a larger such chain. In the above example, after processing all lines, `last[0]` (corresponding to 0192a) would point to 03763, which indeed is the end of the overall `fixup!` chain, and `last[1]` (corresponding to 02f12) would point to 04ecb (which is the last `fixup!` targeting 02f12, but it has 03763 as successor, i.e. it is not the end of overall `fixup!` chain). Reported-by: Paul Ganssle <paul@ganssle.io> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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):