.. _development-workflow: ==================== Development workflow ==================== You already have your own forked copy of the NumPy_ repository, by following :ref:`forking`, :ref:`set-up-fork`, you have configured git_ by following :ref:`configure-git`, and have linked the upstream repository as explained in :ref:`linking-to-upstream`. What is described below is a recommended workflow with Git. Basic workflow ############## In short: 1. Update your ``master`` branch if it's not up to date. Then start a new *feature branch* for each set of edits that you do. See :ref:`below `. Avoid putting new commits in your ``master`` branch. 2. Hack away! See :ref:`below ` 3. Avoid merging other branches into your feature branch while you are working. You can optionally rebase if really needed, see :ref:`below `. 4. When finished: - *Contributors*: push your feature branch to your own Github repo, and :ref:`ask for code review or make a pull request `. - *Core developers* (if you want to push changes without further review):: # First, either (i) rebase on upstream -- if you have only few commits git fetch upstream git rebase upstream/master # or, (ii) merge to upstream -- if you have many related commits git fetch upstream git merge --no-ff upstream/master # Recheck that what is there is sensible git log --oneline --graph git log -p upstream/master.. # Finally, push branch to upstream master git push upstream my-new-feature:master See :ref:`below `. .. note:: It's usually a good idea to use the ``-n`` flag to ``git push`` to check first that you're about to push the changes you want to the place you want. This way of working helps to keep work well organized and the history as clear as possible. .. note:: Do not use ``git pull`` --- this avoids common mistakes if you are new to Git. Instead, always do ``git fetch`` followed by ``git rebase``, ``git merge --ff-only`` or ``git merge --no-ff``, depending on what you intend. .. seealso:: See discussions on `linux git workflow`_, and `ipython git workflow `__. .. _making-a-new-feature-branch: Making a new feature branch =========================== To update your master branch, use:: git fetch upstream git merge upstream/master --ff-only To create a new branch and check it out, use:: git checkout -b my-new-feature upstream/master Generally, you will want to keep this branch also on your public github_ fork of NumPy_. To do this, you `git push`_ this new branch up to your github_ repo. Generally (if you followed the instructions in these pages, and by default), git will have a link to your github_ repo, called ``origin``. You push up to your own repo on github_ with:: git push origin my-new-feature In git >= 1.7 you can ensure that the link is correctly set by using the ``--set-upstream`` option:: git push --set-upstream origin my-new-feature From now on git_ will know that ``my-new-feature`` is related to the ``my-new-feature`` branch in your own github_ repo. .. _editing-workflow: The editing workflow ==================== Overview -------- :: # hack hack git add my_new_file git commit -am 'ENH: some message' # push the branch to your own Github repo git push In more detail -------------- #. Make some changes #. See which files have changed with ``git status`` (see `git status`_). You'll see a listing like this one:: # On branch my-new-feature # Changed but not updated: # (use "git add ..." to update what will be committed) # (use "git checkout -- ..." to discard changes in working directory) # # modified: README # # Untracked files: # (use "git add ..." to include in what will be committed) # # INSTALL no changes added to commit (use "git add" and/or "git commit -a") #. Check what the actual changes are with ``git diff`` (`git diff`_). #. Add any new files to version control ``git add new_file_name`` (see `git add`_). #. To commit all modified files into the local copy of your repo,, do ``git commit -am 'A commit message'``. Note the ``-am`` options to ``commit``. The ``m`` flag just signals that you're going to type a message on the command line. If you leave it out, an editor will open in which you can compose your commit message. For non-trivial commits this is often the better choice. The ``a`` flag - you can just take on faith - or see `why the -a flag?`_ - and the helpful use-case description in the `tangled working copy problem`_. The section on :ref:`commit messages ` below might also be useful. #. To push the changes up to your forked repo on github_, do a ``git push`` (see `git push`). .. _writing-the-commit-message: Writing the commit message -------------------------- Commit messages should be clear and follow a few basic rules. Example:: ENH: add functionality X to numpy.. The first line of the commit message starts with a capitalized acronym (options listed below) indicating what type of commit this is. Then a blank line, then more text if needed. Lines shouldn't be longer than 80 characters. If the commit is related to a ticket, indicate that with "See #3456", "See ticket 3456", "Closes #3456" or similar. Describing the motivation for a change, the nature of a bug for bug fixes or some details on what an enhancement does are also good to include in a commit message. Messages should be understandable without looking at the code changes. A commit message like ``MAINT: fixed another one`` is an example of what not to do; the reader has to go look for context elsewhere. Standard acronyms to start the commit message with are:: API: an (incompatible) API change BLD: change related to building numpy BUG: bug fix DEP: deprecate something, or remove a deprecated object DEV: development tool or utility DOC: documentation ENH: enhancement MAINT: maintenance commit (refactoring, typos, etc.) REV: revert an earlier commit STY: style fix (whitespace, PEP8) TST: addition or modification of tests REL: related to releasing numpy .. _rebasing-on-master: Rebasing on master ================== This updates your feature branch with changes from the upstream `NumPy github`_ repo. If you do not absolutely need to do this, try to avoid doing it, except perhaps when you are finished. First, it can be useful to update your master branch:: # go to the master branch git checkout master # pull changes from github git fetch upstream # update the master branch git rebase upstream/master # push it to your Github repo git push Then, the feature branch:: # go to the feature branch git checkout my-new-feature # make a backup in case you mess up git branch tmp my-new-feature # rebase on master git rebase master If you have made changes to files that have changed also upstream, this may generate merge conflicts that you need to resolve. Finally, remove the backup branch once the rebase succeeded:: git branch -D tmp .. _recovering-from-mess-up: Recovering from mess-ups ------------------------ Sometimes, you mess up merges or rebases. Luckily, in Git it is relatively straightforward to recover from such mistakes. If you mess up during a rebase:: git rebase --abort If you notice you messed up after the rebase:: # reset branch back to the saved point git reset --hard tmp If you forgot to make a backup branch:: # look at the reflog of the branch git reflog show my-feature-branch 8630830 my-feature-branch@{0}: commit: BUG: io: close file handles immediately 278dd2a my-feature-branch@{1}: rebase finished: refs/heads/my-feature-branch onto 11ee694744f2552d 26aa21a my-feature-branch@{2}: commit: BUG: lib: make seek_gzip_factory not leak gzip obj ... # reset the branch to where it was before the botched rebase git reset --hard my-feature-branch@{2} If you didn't actually mess up but there are merge conflicts, you need to resolve those. This can be one of the trickier things to get right. For a good description of how to do this, see http://git-scm.com/book/en/Git-Branching-Basic-Branching-and-Merging#Basic-Merge-Conflicts .. _asking-for-merging: Asking for your changes to be merged with the main repo ======================================================= When you feel your work is finished, you can ask for code review, or directly file a pull request. Asking for code review ---------------------- #. Go to your repo URL - e.g. ``http://github.com/your-user-name/numpy``. #. Click on the *Branch list* button: .. image:: branch_list.png #. Click on the *Compare* button for your feature branch - here ``my-new-feature``: .. image:: branch_list_compare.png #. If asked, select the *base* and *comparison* branch names you want to compare. Usually these will be ``master`` and ``my-new-feature`` (where that is your feature branch name). #. At this point you should get a nice summary of the changes. Copy the URL for this, and post it to the `NumPy mailing list`_, asking for review. The URL will look something like: ``http://github.com/your-user-name/numpy/compare/master...my-new-feature``. There's an example at http://github.com/matthew-brett/nipy/compare/master...find-install-data See: http://github.com/blog/612-introducing-github-compare-view for more detail. The generated comparison, is between your feature branch ``my-new-feature``, and the place in ``master`` from which you branched ``my-new-feature``. In other words, you can keep updating ``master`` without interfering with the output from the comparison. More detail? Note the three dots in the URL above (``master...my-new-feature``) and see :ref:`dot2-dot3`. Filing a pull request --------------------- When you are ready to ask for the merge of your code: #. Go to the URL of your forked repo, say ``http://github.com/your-user-name/numpy.git``. #. Click on the 'Pull request' button: .. image:: pull_button.png Enter a message; we suggest you select only ``NumPy`` as the recipient. The message will go to the NumPy core developers. Please feel free to add others from the list as you like. .. _pushing-to-main: Pushing changes to the main repo ================================ When you have a set of "ready" changes in a feature branch ready for Numpy's ``master`` or ``maintenance/1.5.x`` branches, you can push them to ``upstream`` as follows: 1. First, merge or rebase on the target branch. a) Only a few commits: prefer rebasing:: git fetch upstream git rebase upstream/master See :ref:`above `. b) Many related commits: consider creating a merge commit:: git fetch upstream git merge --no-ff upstream/master 2. Check that what you are going to push looks sensible:: git log -p upstream/master.. git log --oneline --graph 3. Push to upstream:: git push upstream my-feature-branch:master .. note:: Avoid using ``git pull`` here. Additional things you might want to do ###################################### .. _rewriting-commit-history: Rewriting commit history ======================== .. note:: Do this only for your own feature branches. There's an embarassing typo in a commit you made? Or perhaps the you made several false starts you would like the posterity not to see. This can be done via *interactive rebasing*. Suppose that the commit history looks like this:: git log --oneline eadc391 Fix some remaining bugs a815645 Modify it so that it works 2dec1ac Fix a few bugs + disable 13d7934 First implementation 6ad92e5 * masked is now an instance of a new object, MaskedConstant 29001ed Add pre-nep for a copule of structured_array_extensions. ... and ``6ad92e5`` is the last commit in the ``master`` branch. Suppose we want to make the following changes: * Rewrite the commit message for ``13d7934`` to something more sensible. * Combine the commits ``2dec1ac``, ``a815645``, ``eadc391`` into a single one. We do as follows:: # make a backup of the current state git branch tmp HEAD # interactive rebase git rebase -i 6ad92e5 This will open an editor with the following text in it:: pick 13d7934 First implementation pick 2dec1ac Fix a few bugs + disable pick a815645 Modify it so that it works pick eadc391 Fix some remaining bugs # Rebase 6ad92e5..eadc391 onto 6ad92e5 # # Commands: # p, pick = use commit # r, reword = use commit, but edit the commit message # e, edit = use commit, but stop for amending # s, squash = use commit, but meld into previous commit # f, fixup = like "squash", but discard this commit's log message # # If you remove a line here THAT COMMIT WILL BE LOST. # However, if you remove everything, the rebase will be aborted. # To achieve what we want, we will make the following changes to it:: r 13d7934 First implementation pick 2dec1ac Fix a few bugs + disable f a815645 Modify it so that it works f eadc391 Fix some remaining bugs This means that (i) we want to edit the commit message for ``13d7934``, and (ii) collapse the last three commits into one. Now we save and quit the editor. Git will then immediately bring up an editor for editing the commit message. After revising it, we get the output:: [detached HEAD 721fc64] FOO: First implementation 2 files changed, 199 insertions(+), 66 deletions(-) [detached HEAD 0f22701] Fix a few bugs + disable 1 files changed, 79 insertions(+), 61 deletions(-) Successfully rebased and updated refs/heads/my-feature-branch. and the history looks now like this:: 0f22701 Fix a few bugs + disable 721fc64 ENH: Sophisticated feature 6ad92e5 * masked is now an instance of a new object, MaskedConstant If it went wrong, recovery is again possible as explained :ref:`above `. Deleting a branch on github_ ============================ :: git checkout master # delete branch locally git branch -D my-unwanted-branch # delete branch on github git push origin :my-unwanted-branch (Note the colon ``:`` before ``test-branch``. See also: http://github.com/guides/remove-a-remote-branch Several people sharing a single repository ========================================== If you want to work on some stuff with other people, where you are all committing into the same repository, or even the same branch, then just share it via github_. First fork NumPy into your account, as from :ref:`forking`. Then, go to your forked repository github page, say ``http://github.com/your-user-name/numpy`` Click on the 'Admin' button, and add anyone else to the repo as a collaborator: .. image:: pull_button.png Now all those people can do:: git clone git@githhub.com:your-user-name/numpy.git Remember that links starting with ``git@`` use the ssh protocol and are read-write; links starting with ``git://`` are read-only. Your collaborators can then commit directly into that repo with the usual:: git commit -am 'ENH - much better code' git push origin master # pushes directly into your repo Exploring your repository ========================= To see a graphical representation of the repository branches and commits:: gitk --all To see a linear list of commits for this branch:: git log You can also look at the `network graph visualizer`_ for your github_ repo. .. include:: git_links.inc