Command-line tools to make git-svn simple
git-svn-helpers is a collection of command line tools that greatly simplify using git for svn repositories.
Its main goal is to make setting up a local git repository following an existing svn checkout a ‘no-brainer’.
It also addresses using a single git-svn repository for working on multiple checkouts of (usually) different branches and switching between them.
> cd path/to/svn/repo > gitify init
Perform local changes and commit them to git. When ready to push your changes:
> gitify push
To update your working directory with upstream changes:
> gitify update
gitify will take care to keep your git and svn repository in sync and do its best to avoid conflicts when updating.
Here’s a sample session:
> cd /tmp > svn co https://svn.plone.org/svn/plone/plone.app.form/branches/1.1 plone.app.form A 1.1/setup.py ... Checked out revision 27228. > cd plone.app.form > gitify init No git repository found in /Users/tomster/.gitcache/. Initiating cloning into cache. Analyzing svn log... Cloning https://svn.plone.org/svn/plone/plone.app.form/ from r10593:34543 into /Users/tomster/.gitcache/ Initialized empty Git repository in /Users/tomster/Development/gitcache/plone.app.form/.git/ ... Git branch 'local/1.1' is now following svn branch '1.1': # On branch local/1.1 nothing to commit (working directory clean) > git branch * local/1.1 master
Points to note:
- gitify limited the cloning to the revisions found in the svn log of the package root (here https://svn.plone.org/svn/plone/plone.app.form/). A big time saver, especially on large repositories (such as plone.collective)
- gitify created a local branch local/1.1 that follows the (remote) svn branch 1.1 and switched to it
- gitify assumed that the name of the package is the name of the directory it was called from (in this case plone.app.form) as it refuses to guess
In practice you will often work with different local copies of a given repository, i.e. on trunk and on a feature branch. That’s when the .gitcache directory created above comes in handy. Let’s move our previous checkout out of the way and create a maintenance checkout that follows trunk:
> cd .. > mkdir feature-branch > mv plone.app.form feature-branch/ > mkdir maintenance > cd maintenance/ > svn co https://svn.plone.org/svn/plone/plone.app.form/trunk plone.app.form A plone.app.form/setup.py ... U plone.app.form Checked out revision 27228.
What happens if we run gitify here?:
> cd plone.app.form/ > gitify init Updating existing cache: fetching /Users/tomster/.gitcache/plone.app.form Done. 1 packages updated. Git branch 'local/trunk' is now following svn branch 'trunk': # On branch local/trunk nothing to commit (working directory clean)
Notice, that this operation went much faster, as we now have used the existing git repository in the cache directory, thus avoiding the slow and network intensive clone operation.
This can be further evidenced by looking at the available local branches now. Notice how the git repository contains both trunk and the 1.1 branch:
> git branch local/1.1 * local/trunk master
If the svn repository switches to another branch (i.e. due to a change in svn:externals or in a buildout source) the branch git is on differs from the current svn branch. To remedy this you can either manually switch git or just re-run gitify init:
> svn info URL: https://svn.plone.org/svn/plone/plone.app.form/trunk > git branch local/1.1 * local/trunk master
If we switch the svn branch, git initially doesn’t catch the change and the branches differ:
> svn switch https://svn.plone.org/svn/plone/plone.app.form/branches/1.1 > svn info URL: https://svn.plone.org/svn/plone/plone.app.form/branches/1.1 > git branch local/1.1 * local/trunk master
After re-running gitify init they are the same again:
> git branch * local/1.1 local/trunk master
Of course, once you introduce a cache you need to keep it up-to-date. git-svn provides the fetch command for this purpose. In practice it is cumbersome to update each package manually, though. Therefore we provide our own fetch command which can update multiple packages at once using wildcards, like so:
> gitify fetch plone* fetching /Users/tomster/.gitcache/plone.app.form fetching /Users/tomster/.gitcache/plone.pony fetching /Users/tomster/.gitcache/plonenext Done. 3 packages updated.
You can pass the -v option to see the output of the git-svn fetch commands. If you don’t provide a package all packages will be updated.
Note, that the our fetch command never touches any working copy, only the cache. Is primarily intended to be run as a maintenance command, i.e. via crontab to keep the local cache ‘fresh’.
Since the local filesystem is both a git repository, as well as a svn check- out at the same time (IOW we have both .git and .svn floating around) they should be kept in sync as closely as possible. By design, this can only happen, when we have online access to the svn repository. Therefore it is best performed when committing back to svn. The way this is achieved manually is to first dcommit and then perform a svn up --force command (the --force is necessary so that svn won’t be bothered by any new files that have been committed). gitify push provides a convenience command that performs this for you:
> gitify push -v Committing to https://svn.plone.org/svn/plone/plone.app.form/branches/1.1 ... At revision 27229. INFO: Pushed local changes to svn. > svn st <BLANKLINE>
git-svn-helpers requires that git (with subversion support a.k.a git-svn) is already installed.
- add support for custom svn layout
Use full copies instead of symlinks to create working copies. This avoids the issue of having the git and svn repository out of sync when working with multiple copies of the same repository and greatly reduces the risk of conflicts.
This also means, that the fetch command now only operates on the cache without modifying the working copy (making it safe to run via crontab, for example)
Running gitify against an old-style working copy will produce an error. Simply deleting the symlink and re-running gitify remedies that, however.
Another effect, is that the init command is now only needed once for each working copy (it is no longer necessary to re-run the command after switching between different working copies of the same repository).
gitify therefore no longer defaults to the init command (just as neither git nor svn do anything w/o supplying an explicit action). Also, it has been renamed from gitify (back) to init. [tomster]
Allow the help, --version and fetch commands to run outside .svn directories [tomster]