Difference between revisions of "Git"

From GnuCash
Jump to: navigation, search
(bzr now has own page)
(added link to ruby svn2git tool)
Line 242: Line 242:
  
 
sorted.
 
sorted.
 +
 +
== Further Research ==
 +
* http://github.com/jcoglan/svn2git/ a ruby tool for performing imports.

Revision as of 21:21, 17 April 2009

Git is an extremely cool version control system, but a bit geeky to get used to it. For gnucash, it can be used to hold a local copy of the full svn repository, which means extremely fast version browsing. Also, it is possible to prepare your commits in your local repository first, and sending them to the gnucash svn server sometime later in a batch. Also extremely cool.

Note, it might be easier to follow trunk via bazaar.

Webpage: http://git-scm.com/

Note: You should install git >= 1.5.0 because svn handling has improved considerably with these versions. Really. Don't bother with any 1.4 version; it plainly sucks in comparison to the latest versions.

Single Branch Setup

If you want to checkout only one single branch, here's what you would do:

Here's how you as a developer get your local git repository if you only want trunk (git-1.5.2): 

git svn clone -r16500:HEAD svn+ssh://USERNAME@svn.gnucash.org/repo/gnucash/trunk

That's it. The revision subset r16500:HEAD will download approx. 30-40 MB of data. If you download larger revision spans, the download amount might go up into the hundreds of MBs.

Here's how you run the equivalent of "svn update": 

git svn rebase

That's it.

Once you committed your changes to your local git repository, here's how you commit the local changes upstream into gnucash's SVN repository: 

git svn dcommit

Catchup from public clone

clone a public git repo ( http://github.com/timabell/gnucash-svn/ ) that follows the svn server: 

git clone git://github.com/timabell/gnucash-svn.git gnucash.git
cd gnucash.git

attach your copy to the gnucash svn server: 

git svn init -s http://svn.gnucash.org/repo/gnucash/


FIXME: there's got to be a quick way of telling git that it already has enough information about the svn server. I'm sure I did it once before. The below seems to re-fetch everything. --Tim abell 19:59, 4 March 2009 (EST) see http://utsl.gen.nz/talks/git-svn/intro.html#howto-track-rebuildmeta looks like i'm missing metadata on the github copy

update: looks like i'm expecting too much from the git packaged with ubuntu intrepid (1.5.6.3) "You probably also want git 1.6.1rc for incremental rebuild support" http://kerneltrap.org/mailarchive/git/2008/12/7/4338304 --Tim abell 15:51, 5 March 2009 (EST)

fetch changes from the svn server. this will (annoyingly) reread all the commits, but i don't think it takes as long as a full clone. 

git svn fetch

update your copy again (beware that rebase breaks commit references, make sure you are ok with this) 

git svn rebase

push to a public git server so that others can benefit from your more up to date copy

hack on the code

push your own genius new gnucash features to your own public git server for all to see and share :-)

contact the mailing list to get your changes in the mainline.

technical details

svn section of .git/config from original git svn clone: 

[svn-remote "svn"]
	url = http://svn.gnucash.org/repo
	fetch = gnucash/trunk:refs/remotes/trunk
	branches = gnucash/branches/*:refs/remotes/*
	tags = gnucash/tags/*:refs/remotes/tags/*

references

Advanced setup: graft points

There is a git clone on GitHub at http://github.com/timabell/gnucash/ (cloned 31 jan 2009). It is already out of date as GitHub doesn't support tracking remote svn repositories. However, you can use it to efficiently "deepen" the history for a "shallow" checkout of trunk:

1) Checkout trunk as described above. Use the subset r17856:HEAD; we'll get the rest from GitHub. 

git svn clone -r17856:HEAD svn+ssh://USERNAME@svn.gnucash.org/repo/gnucash/trunk

2) Fetch the rest of the history from GitHub. 

git-fetch git://github.com/timabell/gnucash.git

3) Find the latest commit in this history, here is what you should see: 

$ git ls-remote git://github.com/timabell/gnucash.git HEAD
5cabf7a61dee17c188a67d8cdbc4451d1b8ae7de        HEAD
$ git branch history 5cabf7a61dee17c188a67d8cdbc4451d1b8ae7de
$ git log history^..history
commit 5cabf7a61dee17c188a67d8cdbc4451d1b8ae7de
Author: cstim <cstim@57a11ea4-9604-0410-9ed3-97b8803252fd>
Date:   Sat Jan 31 10:24:34 2009 +0000

    Add shell script to easily back-port commits in git-svn from trunk to other branches.

4) Find the corresponding commit from svn: 

$ git svn log --show-commit -r17856
------------------------------------------------------------------------
r17856 | 048f138 | cstim | 2009-01-31 10:24:34 +0000 (Sat, 31 Jan 2009) | 2 lines

Add shell script to easily back-port commits in git-svn from trunk to other branches.

------------------------------------------------------------------------
$ git-rev-parse 048f138
048f1384a4bba73e438615630218568a4446c00f

5) Graft the two histories together: 

$ PARENT=$(git-rev-parse history^)
$ echo 048f1384a4bba73e438615630218568a4446c00f $PARENT >> .git/info/grafts

Multi-Branch Setup

If you want to checkout all of the currently active branches and have the ability to merge and cherry-pick back and forth between all branches locally, here's one way that works:

First of all, it is recommended to use multiple git repositories - one for each branch that you want to work with. This is because when changing between the branches, git would change your working directory, hence everything would need to be rebuilt.

(... FIXME: more text later ...) 

git svn clone -s -r16500:HEAD svn+ssh://USERNAME@svn.gnucash.org/repo/gnucash all
cd all
git branch --track my-trunk remotes/trunk
git branch --track my-2.2 remotes/2.2
cd ..

This will need git svn --fetch-all rebase so that all SVN branches are updated in parallel.

Creating a working copy for trunk: 

cd all
git checkout my-trunk
cd ..
git clone -s all trunk

And another working copy for branches/2.2: 

cd all
git checkout my-2.2
cd ..
git clone -s all 2.2

Building one branch: 

cd 2.2
./autogen.sh
mkdir build
cd build
../configure --some-options-foo-bar --prefix=/opt/experimental .....

(... FIXME: more text later ...)

Here's how you as a developer get your local git repository if you want trunk and all branches (git-1.5.2), pay attention to the -s switch: 

git svn clone -s -r16500:HEAD svn+ssh://USERNAME@svn.gnucash.org/repo/gnucash
git reset --hard remotes/trunk

The latter command is necessary if your local master should represent the trunk of SVN, which is probably what you want. You need reset --hard here instead of rebase because the revision subset r16500:HEAD probably doesn't contain the original branch point between some of the other svn branches and trunk. If the branch point is included in your cloned revision subset, git rebase remotes/trunk would work as well and is safer (i.e. won't throw away any local changes without asking).

Starting at r16500 is a good opportunity because the 2.2 branch is branched at approx. r16560; if you need the gda-dev: that one was created at r15090.

Full import process

As used to create http://github.com/timabell/gnucash-svn

This is mostly just for reference or in case anyone else wants to do the same as me. --Tim abell 16:21, 4 March 2009 (EST)

The idea is to be able to track the bleeding edge in git, with one central shared copy, without requiring the existing devs to move away from svn.

full clone

git svn clone -s http://svn.gnucash.org/repo/gnucash/ gnucash-svn.git
cd gnucash-svn.git

push to github

create github repo (on their website) and then: 

git remote add origin git@github.com:timabell/gnucash-svn.git
git push origin master

to push up the svn metadata: 

git config --add remote.origin.fetch +refs/remotes/*:refs/remotes/*
git push origin

copying branches

for remote in `git branch -r`; do git branch $remote remotes/$remote ; done

Thanks to http://stackoverflow.com/questions/379081/track-all-remote-git-branches-as-local-branches 

git branch -D origin/master

(was duplicated) 

git branch -D trunk

(master will suffice, don't need a second branch to track the bleeding edge) 

git push --all origin

fixing tags

using modified version of http://beardedmagnum.com/2009/02/15/converting-git-svn-tag-branches-to-real-tags/

this creates a local tag for each branch named tag/*

because svn includes a commit as part of tagging, whether or not you change anything, I need to figure out whether any files are affected by the tag commit.

if nothing was changed, i can safely tag the parent commit.

testing if commit changed anything: 

git show --pretty="format:" --name-only tags/1.4.3 | wc -l

outputs 53, so this tag commit includes changes 

git show --pretty="format:" --name-only tags/1.5.0 | wc -l

outputs 0 so this commit can be ignored and the parent commit tagged instead.

testing the output: 

if [ `git show --pretty="format:" --name-only tags/1.5.0 | wc -l` -gt "0" ]; then echo "files changed in tag commit (boo)"; else echo "no changes in tag commit"; fi

putting it all together: 

git for-each-ref refs/heads/tags | cut -d / -f 4- | \
while read ref
do
 if [ `git show --pretty="format:" --name-only tags/$ref | wc -l` -gt "0" ]; then
  #commit contains changes
  git tag $ref tags/$ref
 else
  #no changes, tag parent commit
  git tag $ref tags/$ref^
 fi
done

delete all the old local tag branches: 

git for-each-ref refs/heads/tags | cut -d / -f 3-| xargs git branch -D

push all the new tags to the server: 

git tag | xargs git push origin

remove remote tag branches (if you pushed them like i did) 

git for-each-ref refs/remotes/origin/tags | cut -d / -f 4- | while read ref; do git push origin :refs/heads/$ref; done

or to delete them all at once 

 git for-each-ref refs/remotes/origin/tags | cut -d / -f 4- | sed "s/^/\:refs\/heads\//" | xargs git push origin

passing through updates

Note, I've only had changes on master to handle so far, so that's all I'm documenting. 

git svn rebase
git push origin master

sorted.

Further Research

Retrieved from "https://code.gnucash.org/wiki/index.php?title=Git&oldid=5524"