569 lines
22 KiB
Text
569 lines
22 KiB
Text
Submitting Patches
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==================
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== Guidelines
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Here are some guidelines for people who want to contribute their code
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to this software.
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[[base-branch]]
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=== Decide what to base your work on.
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In general, always base your work on the oldest branch that your
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change is relevant to.
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* A bugfix should be based on `maint` in general. If the bug is not
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present in `maint`, base it on `master`. For a bug that's not yet
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in `master`, find the topic that introduces the regression, and
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base your work on the tip of the topic.
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* A new feature should be based on `master` in general. If the new
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feature depends on a topic that is in `pu`, but not in `master`,
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base your work on the tip of that topic.
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* Corrections and enhancements to a topic not yet in `master` should
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be based on the tip of that topic. If the topic has not been merged
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to `next`, it's alright to add a note to squash minor corrections
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into the series.
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* In the exceptional case that a new feature depends on several topics
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not in `master`, start working on `next` or `pu` privately and send
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out patches for discussion. Before the final merge, you may have to
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wait until some of the dependent topics graduate to `master`, and
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rebase your work.
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* Some parts of the system have dedicated maintainers with their own
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repositories (see the section "Subsystems" below). Changes to
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these parts should be based on their trees.
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To find the tip of a topic branch, run `git log --first-parent
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master..pu` and look for the merge commit. The second parent of this
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commit is the tip of the topic branch.
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[[separate-commits]]
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=== Make separate commits for logically separate changes.
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Unless your patch is really trivial, you should not be sending
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out a patch that was generated between your working tree and
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your commit head. Instead, always make a commit with complete
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commit message and generate a series of patches from your
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repository. It is a good discipline.
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Give an explanation for the change(s) that is detailed enough so
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that people can judge if it is good thing to do, without reading
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the actual patch text to determine how well the code does what
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the explanation promises to do.
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If your description starts to get too long, that's a sign that you
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probably need to split up your commit to finer grained pieces.
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That being said, patches which plainly describe the things that
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help reviewers check the patch, and future maintainers understand
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the code, are the most beautiful patches. Descriptions that summarize
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the point in the subject well, and describe the motivation for the
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change, the approach taken by the change, and if relevant how this
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differs substantially from the prior version, are all good things
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to have.
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Make sure that you have tests for the bug you are fixing. See
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`t/README` for guidance.
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[[tests]]
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When adding a new feature, make sure that you have new tests to show
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the feature triggers the new behavior when it should, and to show the
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feature does not trigger when it shouldn't. After any code change, make
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sure that the entire test suite passes.
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If you have an account at GitHub (and you can get one for free to work
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on open source projects), you can use their Travis CI integration to
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test your changes on Linux, Mac (and hopefully soon Windows). See
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GitHub-Travis CI hints section for details.
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Do not forget to update the documentation to describe the updated
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behavior and make sure that the resulting documentation set formats
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well (try the Documentation/doc-diff script).
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We currently have a liberal mixture of US and UK English norms for
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spelling and grammar, which is somewhat unfortunate. A huge patch that
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touches the files all over the place only to correct the inconsistency
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is not welcome, though. Potential clashes with other changes that can
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result from such a patch are not worth it. We prefer to gradually
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reconcile the inconsistencies in favor of US English, with small and
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easily digestible patches, as a side effect of doing some other real
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work in the vicinity (e.g. rewriting a paragraph for clarity, while
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turning en_UK spelling to en_US). Obvious typographical fixes are much
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more welcomed ("teh -> "the"), preferably submitted as independent
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patches separate from other documentation changes.
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[[whitespace-check]]
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Oh, another thing. We are picky about whitespaces. Make sure your
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changes do not trigger errors with the sample pre-commit hook shipped
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in `templates/hooks--pre-commit`. To help ensure this does not happen,
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run `git diff --check` on your changes before you commit.
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[[describe-changes]]
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=== Describe your changes well.
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The first line of the commit message should be a short description (50
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characters is the soft limit, see DISCUSSION in linkgit:git-commit[1]),
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and should skip the full stop. It is also conventional in most cases to
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prefix the first line with "area: " where the area is a filename or
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identifier for the general area of the code being modified, e.g.
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* doc: clarify distinction between sign-off and pgp-signing
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* githooks.txt: improve the intro section
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If in doubt which identifier to use, run `git log --no-merges` on the
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files you are modifying to see the current conventions.
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[[summary-section]]
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It's customary to start the remainder of the first line after "area: "
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with a lower-case letter. E.g. "doc: clarify...", not "doc:
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Clarify...", or "githooks.txt: improve...", not "githooks.txt:
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Improve...".
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[[meaningful-message]]
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The body should provide a meaningful commit message, which:
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. explains the problem the change tries to solve, i.e. what is wrong
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with the current code without the change.
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. justifies the way the change solves the problem, i.e. why the
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result with the change is better.
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. alternate solutions considered but discarded, if any.
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[[imperative-mood]]
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Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
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instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
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to do frotz", as if you are giving orders to the codebase to change
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its behavior. Try to make sure your explanation can be understood
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without external resources. Instead of giving a URL to a mailing list
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archive, summarize the relevant points of the discussion.
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[[commit-reference]]
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If you want to reference a previous commit in the history of a stable
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branch, use the format "abbreviated sha1 (subject, date)",
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with the subject enclosed in a pair of double-quotes, like this:
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....
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Commit f86a374 ("pack-bitmap.c: fix a memleak", 2015-03-30)
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noticed that ...
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....
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The "Copy commit summary" command of gitk can be used to obtain this
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format, or this invocation of `git show`:
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....
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git show -s --date=short --pretty='format:%h ("%s", %ad)' <commit>
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....
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[[git-tools]]
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=== Generate your patch using Git tools out of your commits.
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Git based diff tools generate unidiff which is the preferred format.
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You do not have to be afraid to use `-M` option to `git diff` or
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`git format-patch`, if your patch involves file renames. The
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receiving end can handle them just fine.
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[[review-patch]]
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Please make sure your patch does not add commented out debugging code,
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or include any extra files which do not relate to what your patch
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is trying to achieve. Make sure to review
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your patch after generating it, to ensure accuracy. Before
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sending out, please make sure it cleanly applies to the `master`
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branch head. If you are preparing a work based on "next" branch,
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that is fine, but please mark it as such.
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[[send-patches]]
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=== Sending your patches.
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:security-ml: footnoteref:[security-ml,The Git Security mailing list: git-security@googlegroups.com]
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Before sending any patches, please note that patches that may be
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security relevant should be submitted privately to the Git Security
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mailing list{security-ml}, instead of the public mailing list.
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Learn to use format-patch and send-email if possible. These commands
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are optimized for the workflow of sending patches, avoiding many ways
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your existing e-mail client that is optimized for "multipart/*" mime
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type e-mails to corrupt and render your patches unusable.
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People on the Git mailing list need to be able to read and
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comment on the changes you are submitting. It is important for
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a developer to be able to "quote" your changes, using standard
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e-mail tools, so that they may comment on specific portions of
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your code. For this reason, each patch should be submitted
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"inline" in a separate message.
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Multiple related patches should be grouped into their own e-mail
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thread to help readers find all parts of the series. To that end,
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send them as replies to either an additional "cover letter" message
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(see below), the first patch, or the respective preceding patch.
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If your log message (including your name on the
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Signed-off-by line) is not writable in ASCII, make sure that
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you send off a message in the correct encoding.
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WARNING: Be wary of your MUAs word-wrap
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corrupting your patch. Do not cut-n-paste your patch; you can
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lose tabs that way if you are not careful.
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It is a common convention to prefix your subject line with
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[PATCH]. This lets people easily distinguish patches from other
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e-mail discussions. Use of markers in addition to PATCH within
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the brackets to describe the nature of the patch is also
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encouraged. E.g. [RFC PATCH] (where RFC stands for "request for
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comments") is often used to indicate a patch needs further
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discussion before being accepted, [PATCH v2], [PATCH v3] etc.
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are often seen when you are sending an update to what you have
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previously sent.
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The `git format-patch` command follows the best current practice to
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format the body of an e-mail message. At the beginning of the
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patch should come your commit message, ending with the
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Signed-off-by: lines, and a line that consists of three dashes,
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followed by the diffstat information and the patch itself. If
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you are forwarding a patch from somebody else, optionally, at
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the beginning of the e-mail message just before the commit
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message starts, you can put a "From: " line to name that person.
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To change the default "[PATCH]" in the subject to "[<text>]", use
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`git format-patch --subject-prefix=<text>`. As a shortcut, you
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can use `--rfc` instead of `--subject-prefix="RFC PATCH"`, or
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`-v <n>` instead of `--subject-prefix="PATCH v<n>"`.
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You often want to add additional explanation about the patch,
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other than the commit message itself. Place such "cover letter"
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material between the three-dash line and the diffstat. For
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patches requiring multiple iterations of review and discussion,
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an explanation of changes between each iteration can be kept in
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Git-notes and inserted automatically following the three-dash
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line via `git format-patch --notes`.
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[[attachment]]
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Do not attach the patch as a MIME attachment, compressed or not.
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Do not let your e-mail client send quoted-printable. Do not let
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your e-mail client send format=flowed which would destroy
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whitespaces in your patches. Many
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popular e-mail applications will not always transmit a MIME
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attachment as plain text, making it impossible to comment on
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your code. A MIME attachment also takes a bit more time to
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process. This does not decrease the likelihood of your
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MIME-attached change being accepted, but it makes it more likely
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that it will be postponed.
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Exception: If your mailer is mangling patches then someone may ask
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you to re-send them using MIME, that is OK.
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[[pgp-signature]]
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Do not PGP sign your patch. Most likely, your maintainer or other people on the
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list would not have your PGP key and would not bother obtaining it anyway.
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Your patch is not judged by who you are; a good patch from an unknown origin
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has a far better chance of being accepted than a patch from a known, respected
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origin that is done poorly or does incorrect things.
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If you really really really really want to do a PGP signed
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patch, format it as "multipart/signed", not a text/plain message
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that starts with `-----BEGIN PGP SIGNED MESSAGE-----`. That is
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not a text/plain, it's something else.
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:security-ml-ref: footnoteref:[security-ml]
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As mentioned at the beginning of the section, patches that may be
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security relevant should not be submitted to the public mailing list
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mentioned below, but should instead be sent privately to the Git
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Security mailing list{security-ml-ref}.
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Send your patch with "To:" set to the mailing list, with "cc:" listing
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people who are involved in the area you are touching (the `git
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contacts` command in `contrib/contacts/` can help to
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identify them), to solicit comments and reviews.
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:current-maintainer: footnote:[The current maintainer: gitster@pobox.com]
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:git-ml: footnote:[The mailing list: git@vger.kernel.org]
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After the list reached a consensus that it is a good idea to apply the
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patch, re-send it with "To:" set to the maintainer{current-maintainer} and "cc:" the
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list{git-ml} for inclusion.
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Do not forget to add trailers such as `Acked-by:`, `Reviewed-by:` and
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`Tested-by:` lines as necessary to credit people who helped your
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patch.
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[[sign-off]]
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=== Certify your work by adding your "Signed-off-by: " line
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To improve tracking of who did what, we've borrowed the
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"sign-off" procedure from the Linux kernel project on patches
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that are being emailed around. Although core Git is a lot
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smaller project it is a good discipline to follow it.
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The sign-off is a simple line at the end of the explanation for
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the patch, which certifies that you wrote it or otherwise have
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the right to pass it on as an open-source patch. The rules are
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pretty simple: if you can certify the below D-C-O:
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[[dco]]
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.Developer's Certificate of Origin 1.1
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____
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By making a contribution to this project, I certify that:
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a. The contribution was created in whole or in part by me and I
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have the right to submit it under the open source license
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indicated in the file; or
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b. The contribution is based upon previous work that, to the best
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of my knowledge, is covered under an appropriate open source
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license and I have the right under that license to submit that
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work with modifications, whether created in whole or in part
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by me, under the same open source license (unless I am
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permitted to submit under a different license), as indicated
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in the file; or
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c. The contribution was provided directly to me by some other
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person who certified (a), (b) or (c) and I have not modified
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it.
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d. I understand and agree that this project and the contribution
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are public and that a record of the contribution (including all
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personal information I submit with it, including my sign-off) is
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maintained indefinitely and may be redistributed consistent with
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this project or the open source license(s) involved.
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____
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then you just add a line saying
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....
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Signed-off-by: Random J Developer <random@developer.example.org>
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....
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This line can be automatically added by Git if you run the git-commit
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command with the -s option.
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Notice that you can place your own Signed-off-by: line when
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forwarding somebody else's patch with the above rules for
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D-C-O. Indeed you are encouraged to do so. Do not forget to
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place an in-body "From: " line at the beginning to properly attribute
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the change to its true author (see (2) above).
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[[real-name]]
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Also notice that a real name is used in the Signed-off-by: line. Please
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don't hide your real name.
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[[commit-trailers]]
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If you like, you can put extra tags at the end:
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. `Reported-by:` is used to credit someone who found the bug that
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the patch attempts to fix.
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. `Acked-by:` says that the person who is more familiar with the area
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the patch attempts to modify liked the patch.
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. `Reviewed-by:`, unlike the other tags, can only be offered by the
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reviewer and means that she is completely satisfied that the patch
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is ready for application. It is usually offered only after a
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detailed review.
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. `Tested-by:` is used to indicate that the person applied the patch
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and found it to have the desired effect.
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You can also create your own tag or use one that's in common usage
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such as "Thanks-to:", "Based-on-patch-by:", or "Mentored-by:".
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== Subsystems with dedicated maintainers
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Some parts of the system have dedicated maintainers with their own
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repositories.
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- `git-gui/` comes from git-gui project, maintained by Pat Thoyts:
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git://repo.or.cz/git-gui.git
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- `gitk-git/` comes from Paul Mackerras's gitk project:
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git://ozlabs.org/~paulus/gitk
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- `po/` comes from the localization coordinator, Jiang Xin:
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https://github.com/git-l10n/git-po/
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Patches to these parts should be based on their trees.
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[[patch-flow]]
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== An ideal patch flow
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Here is an ideal patch flow for this project the current maintainer
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suggests to the contributors:
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. You come up with an itch. You code it up.
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. Send it to the list and cc people who may need to know about
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the change.
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+
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The people who may need to know are the ones whose code you
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are butchering. These people happen to be the ones who are
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most likely to be knowledgeable enough to help you, but
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they have no obligation to help you (i.e. you ask for help,
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don't demand). +git log -p {litdd} _$area_you_are_modifying_+ would
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help you find out who they are.
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. You get comments and suggestions for improvements. You may
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even get them in an "on top of your change" patch form.
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. Polish, refine, and re-send to the list and the people who
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spend their time to improve your patch. Go back to step (2).
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. The list forms consensus that the last round of your patch is
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good. Send it to the maintainer and cc the list.
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. A topic branch is created with the patch and is merged to `next`,
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and cooked further and eventually graduates to `master`.
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In any time between the (2)-(3) cycle, the maintainer may pick it up
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from the list and queue it to `pu`, in order to make it easier for
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people play with it without having to pick up and apply the patch to
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their trees themselves.
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[[patch-status]]
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== Know the status of your patch after submission
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* You can use Git itself to find out when your patch is merged in
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master. `git pull --rebase` will automatically skip already-applied
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patches, and will let you know. This works only if you rebase on top
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of the branch in which your patch has been merged (i.e. it will not
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tell you if your patch is merged in pu if you rebase on top of
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master).
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* Read the Git mailing list, the maintainer regularly posts messages
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entitled "What's cooking in git.git" and "What's in git.git" giving
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the status of various proposed changes.
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[[travis]]
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== GitHub-Travis CI hints
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With an account at GitHub (you can get one for free to work on open
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source projects), you can use Travis CI to test your changes on Linux,
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Mac (and hopefully soon Windows). You can find a successful example
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test build here: https://travis-ci.org/git/git/builds/120473209
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Follow these steps for the initial setup:
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. Fork https://github.com/git/git to your GitHub account.
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You can find detailed instructions how to fork here:
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https://help.github.com/articles/fork-a-repo/
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. Open the Travis CI website: https://travis-ci.org
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. Press the "Sign in with GitHub" button.
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. Grant Travis CI permissions to access your GitHub account.
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You can find more information about the required permissions here:
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https://docs.travis-ci.com/user/github-oauth-scopes
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. Open your Travis CI profile page: https://travis-ci.org/profile
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. Enable Travis CI builds for your Git fork.
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After the initial setup, Travis CI will run whenever you push new changes
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to your fork of Git on GitHub. You can monitor the test state of all your
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branches here: https://travis-ci.org/__<Your GitHub handle>__/git/branches
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If a branch did not pass all test cases then it is marked with a red
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cross. In that case you can click on the failing Travis CI job and
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scroll all the way down in the log. Find the line "<-- Click here to see
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detailed test output!" and click on the triangle next to the log line
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number to expand the detailed test output. Here is such a failing
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example: https://travis-ci.org/git/git/jobs/122676187
|
|
|
|
Fix the problem and push your fix to your Git fork. This will trigger
|
|
a new Travis CI build to ensure all tests pass.
|
|
|
|
[[mua]]
|
|
== MUA specific hints
|
|
|
|
Some of patches I receive or pick up from the list share common
|
|
patterns of breakage. Please make sure your MUA is set up
|
|
properly not to corrupt whitespaces.
|
|
|
|
See the DISCUSSION section of linkgit:git-format-patch[1] for hints on
|
|
checking your patch by mailing it to yourself and applying with
|
|
linkgit:git-am[1].
|
|
|
|
While you are at it, check the resulting commit log message from
|
|
a trial run of applying the patch. If what is in the resulting
|
|
commit is not exactly what you would want to see, it is very
|
|
likely that your maintainer would end up hand editing the log
|
|
message when he applies your patch. Things like "Hi, this is my
|
|
first patch.\n", if you really want to put in the patch e-mail,
|
|
should come after the three-dash line that signals the end of the
|
|
commit message.
|
|
|
|
|
|
=== Pine
|
|
|
|
(Johannes Schindelin)
|
|
|
|
....
|
|
I don't know how many people still use pine, but for those poor
|
|
souls it may be good to mention that the quell-flowed-text is
|
|
needed for recent versions.
|
|
|
|
... the "no-strip-whitespace-before-send" option, too. AFAIK it
|
|
was introduced in 4.60.
|
|
....
|
|
|
|
(Linus Torvalds)
|
|
|
|
....
|
|
And 4.58 needs at least this.
|
|
|
|
diff-tree 8326dd8350be64ac7fc805f6563a1d61ad10d32c (from e886a61f76edf5410573e92e38ce22974f9c40f1)
|
|
Author: Linus Torvalds <torvalds@g5.osdl.org>
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|
Date: Mon Aug 15 17:23:51 2005 -0700
|
|
|
|
Fix pine whitespace-corruption bug
|
|
|
|
There's no excuse for unconditionally removing whitespace from
|
|
the pico buffers on close.
|
|
|
|
diff --git a/pico/pico.c b/pico/pico.c
|
|
--- a/pico/pico.c
|
|
+++ b/pico/pico.c
|
|
@@ -219,7 +219,9 @@ PICO *pm;
|
|
switch(pico_all_done){ /* prepare for/handle final events */
|
|
case COMP_EXIT : /* already confirmed */
|
|
packheader();
|
|
+#if 0
|
|
stripwhitespace();
|
|
+#endif
|
|
c |= COMP_EXIT;
|
|
break;
|
|
....
|
|
|
|
(Daniel Barkalow)
|
|
|
|
....
|
|
> A patch to SubmittingPatches, MUA specific help section for
|
|
> users of Pine 4.63 would be very much appreciated.
|
|
|
|
Ah, it looks like a recent version changed the default behavior to do the
|
|
right thing, and inverted the sense of the configuration option. (Either
|
|
that or Gentoo did it.) So you need to set the
|
|
"no-strip-whitespace-before-send" option, unless the option you have is
|
|
"strip-whitespace-before-send", in which case you should avoid checking
|
|
it.
|
|
....
|
|
|
|
=== Thunderbird, KMail, GMail
|
|
|
|
See the MUA-SPECIFIC HINTS section of linkgit:git-format-patch[1].
|
|
|
|
=== Gnus
|
|
|
|
"|" in the `*Summary*` buffer can be used to pipe the current
|
|
message to an external program, and this is a handy way to drive
|
|
`git am`. However, if the message is MIME encoded, what is
|
|
piped into the program is the representation you see in your
|
|
`*Article*` buffer after unwrapping MIME. This is often not what
|
|
you would want for two reasons. It tends to screw up non ASCII
|
|
characters (most notably in people's names), and also
|
|
whitespaces (fatal in patches). Running "C-u g" to display the
|
|
message in raw form before using "|" to run the pipe can work
|
|
this problem around.
|