===== Developing code for ICON =====

[[models:icon:development:necessary_conditions_to_merge_a_branch_back_to_master|How to merge a branch back to icon-mpim:master]] documents how to merge your changes back to mpim master.  However before embarking on this procedure please clarify with your supervisor if the proposed developments are desired.


==== Working on your own feature branch ====

=== 1) In case you do not have the repository at all ===

  git clone --recursive git@gitlab.dkrz.de:icon/icon-mpim.git


  cd icon-mpim

You are now automatically on 'master', which is our main development branch and serves as reference.

Checkout a new ( feature-/bugfix- ) branch


  git checkout -b feature-<my-branch>


**In case the feature branch already exists you have to skip the -b!** to simply change into the branch

Use the status command to check your status


  git status


The result should look like


  On branch feature-<my-branch>
  nothing to commit, working directory clean


=== 2) Start doing your changes.... ===

...use "git add/rm <file>..." to update what will be committed -> your files will be staged

Check again with


  git status


=== 3) Commit your changes ===

  git commit

The commit message has to begin with [icon-mpim:feature-<my-branch>]. This should be followed by some useful information regarding your commit. 
See "Tips and Tricks":https://wiki.mpimet.mpg.de/doku.php?id=models:icon:tips_and_tricks#add_the_current_repository-_and_branch_name_to_the_commit_message_automatically to build this string automatically

=== 4) Publish your local branch with a different name in our repository: ===


  git push origin feature-<my-branch>:feature-<my-branch>-test001


So this is like pushing your actual branch  to an intermediate copy of your actual branch.

This is necessary for further rebasing of your local feature branch with icon-mpim:master and has some more advantages:
* you can check this version of your branch with buildbot independent of further changes in your local copy
* you have a copy of this state of work
* you can run test experiments with a fixed version of your development

=== 5) Update your (local) branch with master regularly: ===

First you have to add all changes done in the central icon-mpim.git repository to your local copy


  git fetch --all

Then you have to rebase your changes to icon-mpim:master. This might lead to conflicts, as the work on icon-mpim:master is ongoing. It might also lead to differences in the output!


  git rebase  origin/master


Make changes and commit as in 3) and 4).
"Publish" your local branch with a new different name in our central repository, for testing or storage, e.g.:


  git push origin feature-<my-branch>:feature-<my-branch>-test002
  
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 --- //[[monika.esch@mpimet.mpg.de|Monika Esch]] 2022/11/09 10:41//