[PATCH] Add some simple howtos, culled from the mailing list.
I think these are useful, and I think putting them in a new "howto" directory might help some users until we get to the point of splitting up the tutorial to be easier to read. Given the authorship, I think it's safe to put these in the repository. Signed-off-by: Ryan Anderson <ryan@michonline.com>maint
Ryan Anderson
Junio C Hamano
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Date: Fri, 12 Aug 2005 22:39:48 -0700 (PDT)
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From: Linus Torvalds <torvalds@osdl.org>
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To: Dave Jones <davej@redhat.com>
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cc: git@vger.kernel.org
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Subject: Re: Fwd: Re: git checkout -f branch doesn't remove extra files
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On Sat, 13 Aug 2005, Dave Jones wrote:
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>
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> > Git actually has a _lot_ of nifty tools. I didn't realize that people
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> > didn't know about such basic stuff as "git-tar-tree" and "git-ls-files".
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>
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> Maybe its because things are moving so fast :) Or maybe I just wasn't
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> paying attention on that day. (I even read the git changes via RSS,
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> so I should have no excuse).
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Well, git-tar-tree has been there since late April - it's actually one of
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those really early commands. I'm pretty sure the RSS feed came later ;)
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I use it all the time in doing releases, it's a lot faster than creating a
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tar tree by reading the filesystem (even if you don't have to check things
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out). A hidden pearl.
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This is my crappy "release-script":
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[torvalds@g5 ~]$ cat bin/release-script
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#!/bin/sh
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stable="$1"
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last="$2"
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new="$3"
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echo "# git-tag-script v$new"
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echo "git-tar-tree v$new linux-$new | gzip -9 > ../linux-$new.tar.gz"
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echo "git-diff-tree -p v$stable v$new | gzip -9 > ../patch-$new.gz"
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echo "git-rev-list --pretty v$new ^v$last > ../ChangeLog-$new"
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echo "git-rev-list --pretty=short v$new ^v$last | git-shortlog > ../ShortLog"
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echo "git-diff-tree -p v$last v$new | git-apply --stat > ../diffstat-$new"
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and when I want to do a new kernel release I literally first tag it, and
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then do
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release-script 2.6.12 2.6.13-rc6 2.6.13-rc7
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and check that things look sane, and then just cut-and-paste the commands.
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Yeah, it's stupid.
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Linus
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Date: Sat, 13 Aug 2005 22:16:02 -0700 (PDT)
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From: Linus Torvalds <torvalds@osdl.org>
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To: Steve French <smfrench@austin.rr.com>
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cc: git@vger.kernel.org
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Subject: Re: sending changesets from the middle of a git tree
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On Sat, 13 Aug 2005, Linus Torvalds wrote:
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> That's correct. Same things apply: you can move a patch over, and create a
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> new one with a modified comment, but basically the _old_ commit will be
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> immutable.
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Let me clarify.
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You can entirely _drop_ old branches, so commits may be immutable, but
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nothing forces you to keep them. Of course, when you drop a commit, you'll
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always end up dropping all the commits that depended on it, and if you
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actually got somebody else to pull that commit you can't drop it from
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_their_ repository, but undoing things is not impossible.
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For example, let's say that you've made a mess of things: you've committed
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three commits "old->a->b->c", and you notice that "a" was broken, but you
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want to save "b" and "c". What you can do is
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# Create a branch "broken" that is the current code
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# for reference
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git branch broken
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# Reset the main branch to three parents back: this
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# effectively undoes the three top commits
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git reset HEAD^^^
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git checkout -f
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# Check the result visually to make sure you know what's
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# going on
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gitk --all
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# Re-apply the two top ones from "broken"
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#
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# First "parent of broken" (aka b):
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git-diff-tree -p broken^ | git-apply --index
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git commit --reedit=broken^
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# Then "top of broken" (aka c):
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git-diff-tree -p broken | git-apply --index
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git commit --reedit=broken
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and you've now re-applied (and possibly edited the comments) the two
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commits b/c, and commit "a" is basically gone (it still exists in the
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"broken" branch, of course).
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Finally, check out the end result again:
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# Look at the new commit history
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gitk --all
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to see that everything looks sensible.
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And then, you can just remove the broken branch if you decide you really
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don't want it:
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# remove 'broken' branch
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rm .git/refs/heads/broken
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# Prune old objects if you're really really sure
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git prune
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And yeah, I'm sure there are other ways of doing this. And as usual, the
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above is totally untested, and I just wrote it down in this email, so if
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I've done something wrong, you'll have to figure it out on your own ;)
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Linus
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-
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To unsubscribe from this list: send the line "unsubscribe git" in
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the body of a message to majordomo@vger.kernel.org
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More majordomo info at http://vger.kernel.org/majordomo-info.html
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@ -0,0 +1,163 @@
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From: Junio C Hamano <junkio@cox.net>
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To: git@vger.kernel.org
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Cc: Petr Baudis <pasky@suse.cz>, Linus Torvalds <torvalds@osdl.org>
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Subject: Re: sending changesets from the middle of a git tree
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Date: Sun, 14 Aug 2005 18:37:39 -0700
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Petr Baudis <pasky@suse.cz> writes:
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> Dear diary, on Sun, Aug 14, 2005 at 09:57:13AM CEST, I got a letter
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> where Junio C Hamano <junkio@cox.net> told me that...
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>> Linus Torvalds <torvalds@osdl.org> writes:
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>>
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>> > Junio, maybe you want to talk about how you move patches from your "pu"
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>> > branch to the real branches.
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>>
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> Actually, wouldn't this be also precisely for what StGIT is intended to?
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Exactly my feeling. I was sort of waiting for Catalin to speak
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up. With its basing philosophical ancestry on quilt, this is
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the kind of task StGIT is designed to do.
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I just have done a simpler one, this time using only the core
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GIT tools.
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I had a handful commits that were ahead of master in pu, and I
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wanted to add some documentation bypassing my usual habit of
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placing new things in pu first. At the beginning, the commit
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ancestry graph looked like this:
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*"pu" head
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master --> #1 --> #2 --> #3
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So I started from master, made a bunch of edits, and committed:
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$ git checkout master
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$ cd Documentation; ed git.txt git-apply-patch-script.txt ...
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$ cd ..; git add Documentation/*.txt
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$ git commit -s -v
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NOTE. The -v flag to commit is a handy way to make sure that
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your additions are not introducing bogusly formatted lines.
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After the commit, the ancestry graph would look like this:
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*"pu" head
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master^ --> #1 --> #2 --> #3
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\
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\---> master
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The old master is now master^ (the first parent of the master).
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The new master commit holds my documentation updates.
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Now I have to deal with "pu" branch.
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This is the kind of situation I used to have all the time when
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Linus was the maintainer and I was a contributor, when you look
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at "master" branch being the "maintainer" branch, and "pu"
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branch being the "contributor" branch. Your work started at the
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tip of the "maintainer" branch some time ago, you made a lot of
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progress in the meantime, and now the maintainer branch has some
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other commits you do not have yet. And "git rebase" was written
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with the explicit purpose of helping to maintain branches like
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"pu". You _could_ merge master to pu and keep going, but if you
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eventually want to cherrypick and merge some but not necessarily
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all changes back to the master branch, it often makes later
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operations for _you_ easier if you rebase (i.e. carry forward
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your changes) "pu" rather than merge. So I ran "git rebase":
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$ git checkout pu
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$ git rebase master pu
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What this does is to pick all the commits since the current
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branch (note that I now am on "pu" branch) forked from the
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master branch, and forward port these changes.
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master^ --> #1 --> #2 --> #3
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\ *"pu" head
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\---> master --> #1' --> #2' --> #3'
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The diff between master^ and #1 is applied to master and
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committed to create #1' commit with the commit information (log,
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author and date) taken from commit #1. On top of that #2' and #3'
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commits are made similarly out of #2 and #3 commits.
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Old #3 is not recorded in any of the .git/refs/heads/ file
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anymore, so after doing this you will have dangling commit if
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you ran fsck-cache, which is normal. After testing "pu", you
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can run "git prune" to get rid of those original three commits.
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While I am talking about "git rebase", I should talk about how
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to do cherrypicking using only the core GIT tools.
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Let's go back to the earlier picture, with different labels.
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You, as an individual developer, cloned upstream repository and
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amde a couple of commits on top of it.
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*your "master" head
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upstream --> #1 --> #2 --> #3
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You would want changes #2 and #3 incorporated in the upstream,
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while you feel that #1 may need further improvements. So you
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prepare #2 and #3 for e-mail submission.
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$ git format-patch master^^ master
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This creates two files, 0001-XXXX.txt and 0002-XXXX.txt. Send
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them out "To: " your project maintainer and "Cc: " your mailing
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list. You could use contributed script git-send-email-script if
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your host has necessary perl modules for this, but your usual
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MUA would do as long as it does not corrupt whitespaces in the
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patch.
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Then you would wait, and you find out that the upstream picked
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up your changes, along with other changes.
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where *your "master" head
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upstream --> #1 --> #2 --> #3
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used \
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to be \--> #A --> #2' --> #3' --> #B --> #C
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*upstream head
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The two commits #2' and #3' in the above picture record the same
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changes your e-mail submission for #2 and #3 contained, but
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probably with the new sign-off line added by the upsteam
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maintainer and definitely with different committer and ancestry
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information, they are different objects from #2 and #3 commits.
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You fetch from upstream, but not merge.
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$ git fetch upstream
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This leaves the updated upstream head in .git/FETCH_HEAD but
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does not touch your .git/HEAD nor .git/refs/heads/master.
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You run "git rebase" now.
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$ git rebase FETCH_HEAD master
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Earlier, I said that rebase applies all the commits from your
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branch on top of the upstream head. Well, I lied. "git rebase"
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is a bit smarter than that and notices that #2 and #3 need not
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be applied, so it only applies #1. The commit ancestry graph
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becomes something like this:
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where *your old "master" head
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upstream --> #1 --> #2 --> #3
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used \ your new "master" head*
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to be \--> #A --> #2' --> #3' --> #B --> #C --> #1'
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*upstream
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head
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Again, "git prune" would discard the disused commits #1-#3 and
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you continue on starting from the new "master" head, which is
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the #1' commit.
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-jc
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-
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To unsubscribe from this list: send the line "unsubscribe git" in
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the body of a message to majordomo@vger.kernel.org
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More majordomo info at http://vger.kernel.org/majordomo-info.html
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