====== Using git with svn ======

Before continuing to read this page, you have two options:
  - If you are happy with using svn, stop reading here.
  - If you would like to experiment with git, continue reading.

This page has been benefited a lot from the following pages:
  * [[http://www.viget.com/extend/effectively-using-git-with-subversion/|Effectively Using Git With Subversion]]

=====Installing git=====

Install first git and a graphical client (e.g. gitk) for it
<code>
sudo apt-get install git gitk
</code>

=====Applying git clone to the svn repository=====
Create the following ''git-clone-rg-repository.sh'' script in order to clone the repository
<code>
#!/bin/bash
USERNAME=<username>
ERROR_CODE=-1
while [ $ERROR_CODE -ne 0 ]; do
  # repeat until final success
  git svn clone -s https://${USERNAME}@rosegarden.svn.sourceforge.net/svnroot/rosegarden rosegarden.git
  # it may be possible that the commands ends to an error like 'RA layer request failed:'
  let ERROR_CODE=$?
  # just a small pause before repeating the command
  sleep 1
done
echo Finished.
</code>
The clone the repository (takes a long, long time (several, or, even tens of hours) and 662 Mb to fetch all branches) by running the script
<code>
bash ./git-clone-rg-repository.sh
</code>
If the script still fails, end the loop by pressing Ctrl+C and rerun the script.

=====Example commit 1: Generating .gitignore and adding it to the subversion repository=====
(These lines have already been executed once.)

==== Generating .gitignore ====

Generate the ignore file with
<code>
cd rosegarden.git
git-svn show-ignore > .gitignore
</code>

==== Adding file to a following local commit ====

Add the generated file to the local commit
<code>
git add .gitignore
</code>
and check the status of the repository, if you wish
<code>
git status
</code>
the following lines will result
<code>
# On branch master                                         
# Changes to be committed:                                 
#   (use "git reset HEAD <file>..." to unstage)            
#                                                          
#       new file:   .gitignore                             
#    
</code>

==== Committing locally ====

Commit locally the changes
<code>
git commit .gitignore
</code>
write then the comment
<code>
Add .gitignore file as a result of the following command:
 git svn show-ignore > .gitignore
</code>
after writing the comment, save the file in editor and finally quit the editor.
This will commit locally the changes and the following information will be given
<code>
Created commit 4dcfaa7: Add .gitignore file as a result of the following command:
 1 files changed, 181 insertions(+), 0 deletions(-)                              
 create mode 100644 .gitignore                                                   
</code>

==== Fetching latest changes before commit ====

Before committing, you want make sure that you have the latest version of the source
<code>
git svn rebase
</code>
Invoking the above command
  - reverts temporarily the changes you have made
  - downloads all changes from subversion, 
  - applies the downloaded changes from subversion to the previous version downloaded from subversion, and
  - applies again the changes you have made.
The following lines will be printed
<code>
First, rewinding head to replay your work on top of it...                        
Applying: Add .gitignore file as a result of the following command:              
</code>

==== Committing back to subversion ====

Suggesting that there were no code to merge and no conflicts to solve, you can then commit back to subversion
<code>
git svn dcommit
</code>
You will see then the following output
<code>
Committing to https://hjunes@rosegarden.svn.sourceforge.net/svnroot/rosegarden/trunk ...
        A       .gitignore                                                              
Committed r10792                                                                        
        A       .gitignore                                                              
r10792 = 8d3f93067b542f7e770c08a3e84c8fb4bb8fb46f (trunk)                               
No changes between current HEAD and refs/remotes/trunk                                  
Resetting to the latest refs/remotes/trunk                                              
</code>
As you can see, the commit has been assigned subversion's version number 10792.

===== A typical short working cycle =====

First you check for new updates
<code>
git svn rebase
</code>

Then you make your changes, compile and test
<code>
[... editing ...]
make
./rosegarden
</code>

Now lets prepare for the commit. First lets see what changes we are going to commit
<code>
git diff
</code>

Add files which were changed and commit them locally
<code>
git add [file1 file2 ...]
git commit -m "Message..."
</code>

Then one more check for probable new set of changes
<code>
git svn rebase
</code>
No merge was needed in this example.

Finally, submit the changes
<code>
git svn dcommit
</code>

That was it. The above set of commands is not optimal, but it works.

===== Using TEMPORARILY a branch =====

First you may want to **fetch** (the code word) the changes in all branches
<code>
git svn fetch
</code>