KernelTrap - BitKeeper

Git Management

Jeremy — Tue, 20 May 2008 22:47:43 +0000

"Is there a write up of what you consider the 'proper' git workflow?" Theodore Ts'o asked Linux creator Linus Torvalds, "why do you consider rebasing topic branches a bad thing?" Linus replied, "rebasing branches is absolutely not a bad thing for individual developers. But it *is* a bad thing for a subsystem maintainer." He went on to differentiate between 'grunts' who write the code and 'managers' who primarily collect other people's code, "a grunt should use 'git rebase' to keep his own work in line. A technical manager, while he hopefully does some useful work on his own, should strive to make _others_ do as much work as possible, and then 'git rebase' is the wrong thing, because it will always make it harder for the people around you to track your tree and to help you update your tree." Linus compared his own patch management style and productivity from over six years ago before he started using BK and git, to his current style using git:

"You can either try to drink from the firehose and inevitably be bitched about because you're holding something up or not giving something the attention it deserves, or you can try to make sure that you can let others help you. And you'd better select the 'let other people help you', because otherwise you _will_ burn out. It's not a matter of 'if', but of 'when'. [...] And when you're in that kind of ballpark, you should at least think of yourself as being where I was six+ years ago before BK. You should really seriously try to make sure that you are *not* the single point of failure, and you should plan on doing git merges. [...] I think a lot of people are a lot happier with how I can take their work these days than they were six+ years ago."

2.6.26-rc3, "Another Week, Another -rc Release"

Jeremy — Mon, 19 May 2008 14:57:12 +0000

"This time around, we have 60+% of the changes in drivers, notably drives/video and drivers/media, with some infiniband, networking and usb lovin' to fill things out," began Linux creator Linus Torvalds, announcing the 2.6.26-rc3 kernel. "The rest is (as usual) mostly arch updates," he continued, "this time mostly mips, m68k and uml." Linus noticed that Linux kernel development has been managed with git now as long as it was managed with BitKeeper, a little over three years for both tools. He explained, "the most striking difference has nothing to do with git or BK (the switch-over timing was just the reason I decided to take a look), but with the fact that we're not just continuing to develop, but we're developing faster and with more people," adding:

"So during the three years 2002->2005, we had 63,428 commits, attributed to 1,560 different authors (caveat: misspellings etc will mean that some people get counted more than once). During the last three years, we've had 96,885 attributed to 4,068 distinct authors (with the same caveat, obviously).

"I didn't do a lot of per-commit statistics yet, but from the little I've done it also seems like we've gotten increasingly better at doing small commits (which is probably one of the reasons we have a larger number of them, but also why we have more authors - small commits is how people get into doing kernel development)."

Git 1.5.5, "Available at the Usual Places"

Jeremy — Wed, 09 Apr 2008 16:26:12 +0000

"The latest feature release GIT 1.5.5 is available at the usual places," began Git maintainer Junio Hamano, adding "we kept this cycle just slightly over two months, as the previous 1.5.4 cycle was painfully tooooo long."

Git is a distributed version control system that was originally written by Linus Torvalds in April of 2005. It was written to be only a temporary replacement for BitKeeper, which Linus had been using to manage kernel source code since February of 2002. Junio Hamano took over maintainership of Git in July of 2005, and the tool has long since become quite popular outside of even Linux kernel development. Regarding the latest stable release, Junio highlighted some of the changes, including:

"Comes with git-gui 0.10.1; bunch of portability improvement patches coming from an effort to port to Solaris has been applied; 'git fetch' over the native git protocol used to make a connection to find out the set of current remote refs and another to actually download the pack data. We now use only one connection for these tasks; 'git commit' does not run lstat(2) more than necessary anymore; bash completion script (in contrib) are aware of more commands and options; a catch-all 'color.ui' configuration variable can be used to enable coloring of all color-capable commands, instead of individual ones such as 'color.status' and 'color.branch'; bash completion's prompt helper function can talk about operation in-progress (e.g. merge, rebase, etc.); 'git help' can use different backends to show manual pages and this can be configured using 'man.viewer' configuration; 'git gui' learned an auto-spell checking; 'git checkout' and 'git remote' are rewritten in C; two conflict hunks that are separated by a very short span of common lines are now coalesced into one larger hunk, to make the result easier to read."

GIT 1.5.4, "An Unusually Long Cycle"

Jeremy — Sat, 02 Feb 2008 20:13:29 +0000

"The latest feature release GIT 1.5.4 is available at the usual places," began Git maintainer Junio Hamano. He continued, "it has been an unusually long cycle. 5 months since the last feature release 1.5.3 was really a bit too long. But I hope it was worth waiting for. Thanks everybody for working hard to improve it." He noted that there were 165 contributers resulting in 684 changed files, included 70,435 insertions and 28,984 deletions.

The Git distributed version control system was originally written by Linus Torvalds in April of 2005 to temporarily replace BitKeeper, which he had been using to manage kernel source code since February of 2002. Junio Hamano took over maintainership of Git a few months later, in July of 2005, and the tool has long since become quite popular outside of even Linux kernel development. Regarding the latest stable release, Junio highlighted some of the changes, including:

"Comes with much improved gitk, with i18n; comes with git-gui 0.9.2 with i18n; progress displays from many commands are a lot nicer to the eye; rename detection of diff family while detecting exact matches has been greatly optimized; 'git diff' sometimes did not quote paths with funny characters properly; various Perforce importer updates; 'git clean' has been rewritten in C; 'git push' learned --dry-run option to show what would happen if a push is run; 'cvs' is recognized as a synonym for 'git cvsserver', so that CVS users can be switched to git just by changing their login shell; 'git add -i' UI has been colorized; 'git commit' has been rewritten in C; 'git bisect' learned 'skip' action to mark untestable commits; 'git svn' wasted way too much disk to record revision mappings between svn and git, a new representation that is much more compact for this information has been introduced to correct this; in addition there are quite a few internal clean-ups."

Linux: Historical Kernel Tree with Git

Jeremy — Wed, 25 Jul 2007 18:44:49 +0000

In a recent lkml thread, the idea of getting the entire Linux kernel history into a git repository was discussed. Linus Torvalds noted, "I actually tried to get something like this together back in the BK days and early in the SCO saga. It was pretty painful to try to find all the historic trees and patches - they're all in different format, and some of them are unreliable." He added, "I've been thinking about trying to re-create some really old history into git, but it's still a lot of work.. And obviously not very useful, just interesting from an archaeological standpoint." Much information on early Linux kernels is gathered at oldlinux.org, and Linus already has the full 2.5.0 to 2.6.12-rc2 history imported from BitKeeper available in git. Linus went on to talk about why git is better suited than BK was for building a complete kernel history:

"The good news is that git would be a lot more natural to the process of trying to create a history, because you could basically import random trees, and tag them as just independent trees, and then re-create the history after-the-fact by trying to stitch them all together. And if you find a new tree, you'd just re-stitch it - something that was very hard to do with BK (and BK generally wouldn't help you with keeping multiple independent trees around, and wouldn't generally accept the notion of re-doing the histories and keeping various versions of the histories around)."

Linux: Git Homepage

Jeremy — Mon, 08 Aug 2005 13:48:31 +0000

Petr Baudis announced the creation of a homepage for git, the directory content manager used to manage the Linux kernel. Git was originally written by Linus Torvalds in early April of 2005 [story], and is now maintained by Junio Hamano [story]. Other online resources available for the tool include a tutorial that walks through the process of setting up and using git, a man page, and the gitweb interface providing easy browsing of the many kernel trees managed by git. The new webpage explains:

"GIT falls into the category of distributed source code management tools, similar to Arch or Darcs (or, in the commercial world, BitKeeper). Every GIT working directory is a full-fledged repository with full revision tracking capabilities, not dependent on network access to a central server."

Linux: Junio Hamano New Git Maintainer

Jeremy — Thu, 28 Jul 2005 13:37:54 +0000

The git directory content manager was born in early April of 2005 [story], less than a week after the announcement that BitKeeper would no longer be available free of charge to kernel developers [story]. The tool was originally written by Linux creator Linus Torvalds, and rapidly evolved with the help of an active developer community which Linus repeatedly noted he hoped would eventually take over [story]. A scant two months after development on the tool began, the 2.6.12 kernel was released, managed by git [story].

Now, Linus has announced that Junio Hamano is the new git maintainer. "I always said I didn't really want to maintain it in the long run," Linus explained, "and maybe some of you thought I was just saying that, especially as the weeks dragged out to over three months, but hey, that's just because this thing ended up being a bit bigger and more professional than I originally even envisioned." He went on to note that Junio was the obvious choice, and that this change means he will be able to return his full focus to the Linux Kernel mailing list.

Junio thanked those involved, described his development methods, and discussed the upcoming 1.0 release. Regarding 1.0, he suggested that all features are in, and that he is primarily looking for bugfixes and documentation updates. Following the announcement, Ryan Anderson posted an updated "Git 1.0 Synopis", a brief overview of the tool and its features. His document begins, "Git, sometimes called 'global information tracker', is a 'directory content manager'. Git has been designed to handle absolutely massive projects with speed and efficiency, and the release of the 2.6.12 and (soon) the 2.6.13 version of the Linux kernel would indicate that it does this task well."

Linux: 2.6.12 Available, The First Git Release

Jeremy — Sat, 18 Jun 2005 17:07:10 +0000

Nearly three and a half months since the last stable release, Linus Torvalds announced the availability of version 2.6.12 of the Linux Kernel. He notes that the changes since -rc6 are minimal, "as you can see from the appended diffstat, most of the things are pretty small (ie it looks like a long list, and then you look at the diffstat and realize that most of the changes end up being just a line or two)." He adds, "one of the least important changes is still worth pointing out," talking about the recent update to the Developer's Certificate of Origin [story]. "The sign-off procedure was clarified to make it clear that the person signing off understands that the project - and thus the patch and the sign-off itself, of course - is public and will be archived."

This is the first stable release of the Linux kernel since the source code was moved out of BitKeeper in early April of 2005 [story]. 2.6.12-rc3, released in late April, was the first release candidate kernel managed by Git [story], thus Linus' git repository only holds changes since 2.6.12-rc2. Due to this fact, Linus did not release a complete changelog between 2.6.11 [story] and 2.6.12. He explains, "the full ChangeLog ended up missing, because I only have the history from 2.6.12-rc2 in my git archives, but if you want to, you can puzzle it together by taking the 2.6.12 changelog and merging it with the -rc1 and -rc2 logs in the testing directory." The latest version of the Linux kernel can be obtained directly from the kernel.org archive [story], or your nearest kernel archives mirror.