Projects/KDE on Windows/Development Workflow
Development Workflow for KDE on Windows
Before we start: This page will not tell you how to diagnose and address problems or shortcomings in source code and build files. We assume you know all that already, or are willing to read up on any missing bits, on your own (but for some hints on useful tools and techniques, be sure to visit Development/Tutorials/Debugging/Debugging on MS Windows, and Projects/KDE on Windows/Tools. The pupose of this page is to give you an outline of the specific steps needed for preparing, testing, and publishing patches in the KDE on Windows project.
You are using emerge to build your KDE on Windows development environment, right? If not, start doing so now. It's mandatory. Some variables to check in your emerge setup:
- EMERGE_BUILDTYPE: You may want to set this to "Debug"
- EMERGE_LOG_DIR: Setting this is highly useful, so you can review (long) build logs.
- GIT_AUTHOR_*/GIT_COMMITTER_*: Useful if you want to be able to make commits directly from your source tree.
- Be sure you are on the branch you want to be on!
Where are the emerge build files?
Often some builds will fail for trivial reasons, like a download failing because the file has moved. This type of error (but also missing or wrong configuration options, and many others) can be corrected in the emerge build files. These are in (subdirectories of) emerge/portage/. Each package has its own subdirectory. In each subdirectory you will find at least one .py-file. I am not aware of any in-depth information on the semantics of these files, but most concepts should be fairly obvious, and if you are unsure, look at other build files for examples.
Where are the sources?
If the problem needs fixing somewhere inside the source tree, you may be wondering where to look for the sources.
- git-based sources are in subdirectories of %KDEROOT%/git
- svn-based sources inside the KDE svn are in %KDEROOT%/svn
- svn-based sources from external repos are in subdirectories of %KDEROOT%/download/svn-src
- archived sources are first downloaded to %KDEROOT%/download. Then, the archives get unpacked to %KDEROOT%/build/category/packagename/work/ .
Debugging and testing
When developing a fix on the level of a package's source code, first locate the final source tree, as detailed above. You do your work directly in the source tree. For quick testing, you can cd to the build directory (%KDEROOT%/build/category/packagename/work/compiler_buildtype-version). Assuming configuration is already complete you can often build directly from there (for MinGW4 use
You can also use
emerge --update to run the build script, without discarding your changes (TODO: Does this apply to all packages, or only svn / git based ones?).
When satisfied with your fix, create a patch with
emerge --createpatch packagename. This will automatically diff your changes against an unmodified source tree, and create a suitable diff. It will be stored in %KDEROOT%/build/category/packagename/.
Next, you will copy this patch to the directory of the package's emerge build script. Add it to the build script using
self.patchToApply[ 'package_version' ] = [( 'patch_file_name.diff' , 1 ), optionally further patches]
Don't forget to test your patch for a clean workdir:
emerge --cleanbuild packagename emerge packagename
TODO: When should build scripts be renamed to reflect newer version? Ever?
Of course in many cases your fix should really become part of the "upstream" package source code. In particular, when patching KDE, you will probably want to commit your fixes to the KDE git repository, directly, in additon (when building an already finalized release of KDE), or instead of creating an emerge patch.
Review and Pushing
If you are confident in your patch, here's an extremely reduced overview of the git commands involved in getting it included:
git add all files that you have touched git commit with a meaningful message, please git log # and git status # to review your work. git status should typically say "1 commit ahead of origin". # Important: If git status shows more than one commit, and you don't know why, ask for help! git pull --rebase # To synchronize with the central repository git push
Which branches should you push your fix to?
More often than not, your fix is relevant to more than one branch of KDE. Typically you will do your work on the latest release branch (kde-4.10 at the time of this writing), and merge your changes into master (which will be the basis of future releases). There is no formal policy on which old branches (former release branches such as kde-4.7) remain supported, however it does make sense to keep branches for at least some time, even after a new series of KDE has been created.
In general you should first commit/push your fix to the oldest branch that it applies to. After that, merge it into the more recent branches, up to (and including) master. Branches before kde-4.10 were not git mergeable, so you would do cherry-picking like this:
git checkout kde-4.10 && git pull origin kde-4.10 git cherry-pick commit_on_previous_branch # possibly more than one commit to cherry-pick git log && git status # always review before pushing git push origin kde-4.10
Branches from kde-4.10 onwards are mergeable, so once your fix is in kde-4.10, you should use:
git checkout kde-4.11 && git pull origin kde-4.11 git merge origin kde-4.10 # resolve conflicts if needed git log && git status # always review before pushing git push origin kde-4.11
Rinse and repeat for every existing release branch (let's say that's kde-4.15), then finally repeat once more for master:
git checkout master && git pull origin master git merge origin kde-4.15 # resolve conflicts if needed git log && git status # always review before pushing git push origin master
In case a fix is already on a later branch, but needs to be applied to an earlier branch, use cherry-picking:
git checkout kde-4.7 && git pull origin kde-4.7 git cherry-pick commit_on_later_branch # possibly more than one commit to cherry-pick git log && git status # always review before pushing git push origin kde-4.7
TODO: Will it be possible to back-merge from 4.11 to 4.10?