-Checklist (and a short version for the impatient):
-
- Commits:
-
- - make commits of logical units
- - check for unnecessary whitespace with "git diff --check"
- before committing
- - do not check in commented out code or unneeded files
- - the first line of the commit message should be a short
- description and should skip the full stop
- - the body should provide a meaningful commit message, which:
- - uses the imperative, present tense: "change",
- not "changed" or "changes".
- - includes motivation for the change, and contrasts
- its implementation with previous behaviour
- - if you want your work included in git.git, add a
- "Signed-off-by: Your Name <you@example.com>" line to the
- commit message (or just use the option "-s" when
- committing) to confirm that you agree to the Developer's
- Certificate of Origin
- - make sure that you have tests for the bug you are fixing
- - make sure that the test suite passes after your commit
-
- Patch:
-
- - use "git format-patch -M" to create the patch
- - do not PGP sign your patch
- - do not attach your patch, but read in the mail
- body, unless you cannot teach your mailer to
- leave the formatting of the patch alone.
- - be careful doing cut & paste into your mailer, not to
- corrupt whitespaces.
- - provide additional information (which is unsuitable for
- the commit message) between the "---" and the diffstat
- - if you change, add, or remove a command line option or
- make some other user interface change, the associated
- documentation should be updated as well.
- - if your name is not writable in ASCII, make sure that
- you send off a message in the correct encoding.
- - send the patch to the list (git@vger.kernel.org) and the
- maintainer (gitster@pobox.com) if (and only if) the patch
- is ready for inclusion. If you use git-send-email(1),
- please test it first by sending email to yourself.
-
-Long version:
-
-I started reading over the SubmittingPatches document for Linux
-kernel, primarily because I wanted to have a document similar to
-it for the core GIT to make sure people understand what they are
-doing when they write "Signed-off-by" line.
-
-But the patch submission requirements are a lot more relaxed
-here on the technical/contents front, because the core GIT is
-thousand times smaller ;-). So here is only the relevant bits.
+Here are some guidelines for people who want to contribute their code
+to this software.
+(0) Decide what to base your work on.
+
+In general, always base your work on the oldest branch that your
+change is relevant to.
+
+ - A bugfix should be based on 'maint' in general. If the bug is not
+ present in 'maint', base it on 'master'. For a bug that's not yet
+ in 'master', find the topic that introduces the regression, and
+ base your work on the tip of the topic.
+
+ - A new feature should be based on 'master' in general. If the new
+ feature depends on a topic that is in 'pu', but not in 'master',
+ base your work on the tip of that topic.
+
+ - Corrections and enhancements to a topic not yet in 'master' should
+ be based on the tip of that topic. If the topic has not been merged
+ to 'next', it's alright to add a note to squash minor corrections
+ into the series.
+
+ - In the exceptional case that a new feature depends on several topics
+ not in 'master', start working on 'next' or 'pu' privately and send
+ out patches for discussion. Before the final merge, you may have to
+ wait until some of the dependent topics graduate to 'master', and
+ rebase your work.
+
+ - Some parts of the system have dedicated maintainers with their own
+ repositories (see the section "Subsystems" below). Changes to
+ these parts should be based on their trees.
+
+To find the tip of a topic branch, run "git log --first-parent
+master..pu" and look for the merge commit. The second parent of this
+commit is the tip of the topic branch.
(1) Make separate commits for logically separate changes.
commit message and generate a series of patches from your
repository. It is a good discipline.
-Describe the technical detail of the change(s).
+Give an explanation for the change(s) that is detailed enough so
+that people can judge if it is good thing to do, without reading
+the actual patch text to determine how well the code does what
+the explanation promises to do.
If your description starts to get too long, that's a sign that you
probably need to split up your commit to finer grained pieces.
the code, are the most beautiful patches. Descriptions that summarise
the point in the subject well, and describe the motivation for the
change, the approach taken by the change, and if relevant how this
-differs substantially from the prior version, can be found on Usenet
-archives back into the late 80's. Consider it like good Netiquette,
-but for code.
+differs substantially from the prior version, are all good things
+to have.
+
+Make sure that you have tests for the bug you are fixing.
+
+When adding a new feature, make sure that you have new tests to show
+the feature triggers the new behaviour when it should, and to show the
+feature does not trigger when it shouldn't. Also make sure that the
+test suite passes after your commit. Do not forget to update the
+documentation to describe the updated behaviour.
Oh, another thing. I am picky about whitespaces. Make sure your
changes do not trigger errors with the sample pre-commit hook shipped
run git diff --check on your changes before you commit.
-(1a) Try to be nice to older C compilers
+(2) Describe your changes well.
+
+The first line of the commit message should be a short description (50
+characters is the soft limit, see DISCUSSION in git-commit(1)), and
+should skip the full stop. It is also conventional in most cases to
+prefix the first line with "area: " where the area is a filename or
+identifier for the general area of the code being modified, e.g.
-We try to support a wide range of C compilers to compile
-git with. That means that you should not use C99 initializers, even
-if a lot of compilers grok it.
+ . archive: ustar header checksum is computed unsigned
+ . git-cherry-pick.txt: clarify the use of revision range notation
-Also, variables have to be declared at the beginning of the block
-(you can check this with gcc, using the -Wdeclaration-after-statement
-option).
+If in doubt which identifier to use, run "git log --no-merges" on the
+files you are modifying to see the current conventions.
-Another thing: NULL pointers shall be written as NULL, not as 0.
+The body should provide a meaningful commit message, which:
+ . explains the problem the change tries to solve, iow, what is wrong
+ with the current code without the change.
-(2) Generate your patch using git tools out of your commits.
+ . justifies the way the change solves the problem, iow, why the
+ result with the change is better.
-git based diff tools (git, Cogito, and StGIT included) generate
-unidiff which is the preferred format.
+ . alternate solutions considered but discarded, if any.
+
+Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
+instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
+to do frotz", as if you are giving orders to the codebase to change
+its behaviour. Try to make sure your explanation can be understood
+without external resources. Instead of giving a URL to a mailing list
+archive, summarize the relevant points of the discussion.
+
+
+(3) Generate your patch using git tools out of your commits.
+
+git based diff tools generate unidiff which is the preferred format.
You do not have to be afraid to use -M option to "git diff" or
"git format-patch", if your patch involves file renames. The
receiving end can handle them just fine.
-Please make sure your patch does not include any extra files
-which do not belong in a patch submission. Make sure to review
+Please make sure your patch does not add commented out debugging code,
+or include any extra files which do not relate to what your patch
+is trying to achieve. Make sure to review
your patch after generating it, to ensure accuracy. Before
sending out, please make sure it cleanly applies to the "master"
branch head. If you are preparing a work based on "next" branch,
that is fine, but please mark it as such.
-(3) Sending your patches.
+(4) Sending your patches.
People on the git mailing list need to be able to read and
comment on the changes you are submitting. It is important for
a developer to be able to "quote" your changes, using standard
e-mail tools, so that they may comment on specific portions of
your code. For this reason, all patches should be submitted
-"inline". WARNING: Be wary of your MUAs word-wrap
+"inline". If your log message (including your name on the
+Signed-off-by line) is not writable in ASCII, make sure that
+you send off a message in the correct encoding.
+
+WARNING: Be wary of your MUAs word-wrap
corrupting your patch. Do not cut-n-paste your patch; you can
lose tabs that way if you are not careful.
You often want to add additional explanation about the patch,
other than the commit message itself. Place such "cover letter"
-material between the three dash lines and the diffstat.
+material between the three dash lines and the diffstat. Git-notes
+can also be inserted using the `--notes` option.
Do not attach the patch as a MIME attachment, compressed or not.
Do not let your e-mail client send quoted-printable. Do not let
that starts with '-----BEGIN PGP SIGNED MESSAGE-----'. That is
not a text/plain, it's something else.
-Note that your maintainer does not necessarily read everything
-on the git mailing list. If your patch is for discussion first,
-send it "To:" the mailing list, and optionally "cc:" him. If it
-is trivially correct or after the list reached a consensus, send
-it "To:" the maintainer and optionally "cc:" the list for
-inclusion.
+Send your patch with "To:" set to the mailing list, with "cc:" listing
+people who are involved in the area you are touching (the output from
+"git blame $path" and "git shortlog --no-merges $path" would help to
+identify them), to solicit comments and reviews.
-Also note that your maintainer does not actively involve himself in
-maintaining what are in contrib/ hierarchy. When you send fixes and
-enhancements to them, do not forget to "cc: " the person who primarily
-worked on that hierarchy in contrib/.
+After the list reached a consensus that it is a good idea to apply the
+patch, re-send it with "To:" set to the maintainer [*1*] and "cc:" the
+list [*2*] for inclusion.
+Do not forget to add trailers such as "Acked-by:", "Reviewed-by:" and
+"Tested-by:" lines as necessary to credit people who helped your
+patch.
-(4) Sign your work
+ [Addresses]
+ *1* The current maintainer: gitster@pobox.com
+ *2* The mailing list: git@vger.kernel.org
+
+
+(5) Sign your work
To improve tracking of who did what, we've borrowed the
"sign-off" procedure from the Linux kernel project on patches
Also notice that a real name is used in the Signed-off-by: line. Please
don't hide your real name.
-Some people also put extra tags at the end.
+If you like, you can put extra tags at the end:
+
+1. "Reported-by:" is used to credit someone who found the bug that
+ the patch attempts to fix.
+2. "Acked-by:" says that the person who is more familiar with the area
+ the patch attempts to modify liked the patch.
+3. "Reviewed-by:", unlike the other tags, can only be offered by the
+ reviewer and means that she is completely satisfied that the patch
+ is ready for application. It is usually offered only after a
+ detailed review.
+4. "Tested-by:" is used to indicate that the person applied the patch
+ and found it to have the desired effect.
-"Acked-by:" says that the patch was reviewed by the person who
-is more familiar with the issues and the area the patch attempts
-to modify. "Tested-by:" says the patch was tested by the person
-and found to have the desired effect.
+You can also create your own tag or use one that's in common usage
+such as "Thanks-to:", "Based-on-patch-by:", or "Mentored-by:".
+
+------------------------------------------------
+Subsystems with dedicated maintainers
+
+Some parts of the system have dedicated maintainers with their own
+repositories.
+
+ - git-gui/ comes from git-gui project, maintained by Pat Thoyts:
+
+ git://repo.or.cz/git-gui.git
+
+ - gitk-git/ comes from Paul Mackerras's gitk project:
+
+ git://ozlabs.org/~paulus/gitk
+
+ - po/ comes from the localization coordinator, Jiang Xin:
+
+ https://github.com/git-l10n/git-po/
+
+Patches to these parts should be based on their trees.
------------------------------------------------
An ideal patch flow
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. Here are two common ones
-I have seen:
-
-* Empty context lines that do not have _any_ whitespace.
-
-* Non empty context lines that have one extra whitespace at the
- beginning.
+properly not to corrupt whitespaces.
-One test you could do yourself if your MUA is set up correctly is:
+See the DISCUSSION section of git-format-patch(1) for hints on
+checking your patch by mailing it to yourself and applying with
+git-am(1).
-* Send the patch to yourself, exactly the way you would, except
- To: and Cc: lines, which would not contain the list and
- maintainer address.
-
-* Save that patch to a file in UNIX mailbox format. Call it say
- a.patch.
-
-* Try to apply to the tip of the "master" branch from the
- git.git public repository:
-
- $ git fetch http://kernel.org/pub/scm/git/git.git master:test-apply
- $ git checkout test-apply
- $ git reset --hard
- $ git am a.patch
-
-If it does not apply correctly, there can be various reasons.
-
-* Your patch itself does not apply cleanly. That is _bad_ but
- does not have much to do with your MUA. Please rebase the
- patch appropriately.
-
-* Your MUA corrupted your patch; "am" would complain that
- the patch does not apply. Look at .git/rebase-apply/ subdirectory and
- see what 'patch' file contains and check for the common
- corruption patterns mentioned above.
-
-* While you are at it, check what are in 'info' and
- 'final-commit' files as well. If what is in 'final-commit' is
- not exactly what you would want to see in the commit log
- message, 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.
+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
it.
-Thunderbird
------------
-
-(A Large Angry SCM)
-
-By default, Thunderbird will both wrap emails as well as flag them as
-being 'format=flowed', both of which will make the resulting email unusable
-by git.
+Thunderbird, KMail, GMail
+-------------------------
-Here are some hints on how to successfully submit patches inline using
-Thunderbird.
-
-There are two different approaches. One approach is to configure
-Thunderbird to not mangle patches. The second approach is to use
-an external editor to keep Thunderbird from mangling the patches.
-
-Approach #1 (configuration):
-
-This recipe is current as of Thunderbird 2.0.0.19. Three steps:
- 1. Configure your mail server composition as plain text
- Edit...Account Settings...Composition & Addressing,
- uncheck 'Compose Messages in HTML'.
- 2. Configure your general composition window to not wrap
- Edit..Preferences..Composition, wrap plain text messages at 0
- 3. Disable the use of format=flowed
- Edit..Preferences..Advanced..Config Editor. Search for:
- mailnews.send_plaintext_flowed
- toggle it to make sure it is set to 'false'.
-
-After that is done, you should be able to compose email as you
-otherwise would (cut + paste, git-format-patch | git-imap-send, etc),
-and the patches should not be mangled.
-
-Approach #2 (external editor):
-
-This recipe appears to work with the current [*1*] Thunderbird from Suse.
-
-The following Thunderbird extensions are needed:
- AboutConfig 0.5
- http://aboutconfig.mozdev.org/
- External Editor 0.7.2
- http://globs.org/articles.php?lng=en&pg=8
-
-1) Prepare the patch as a text file using your method of choice.
-
-2) Before opening a compose window, use Edit->Account Settings to
-uncheck the "Compose messages in HTML format" setting in the
-"Composition & Addressing" panel of the account to be used to send the
-patch. [*2*]
-
-3) In the main Thunderbird window, _before_ you open the compose window
-for the patch, use Tools->about:config to set the following to the
-indicated values:
- mailnews.send_plaintext_flowed => false
- mailnews.wraplength => 0
-
-4) Open a compose window and click the external editor icon.
-
-5) In the external editor window, read in the patch file and exit the
-editor normally.
-
-6) Back in the compose window: Add whatever other text you wish to the
-message, complete the addressing and subject fields, and press send.
-
-7) Optionally, undo the about:config/account settings changes made in
-steps 2 & 3.
-
-
-[Footnotes]
-*1* Version 1.0 (20041207) from the MozillaThunderbird-1.0-5 rpm of Suse
-9.3 professional updates.
-
-*2* It may be possible to do this with about:config and the following
-settings but I haven't tried, yet.
- mail.html_compose => false
- mail.identity.default.compose_html => false
- mail.identity.id?.compose_html => false
-
-(Lukas Sandström)
-
-There is a script in contrib/thunderbird-patch-inline which can help
-you include patches with Thunderbird in an easy way. To use it, do the
-steps above and then use the script as the external editor.
+See the MUA-SPECIFIC HINTS section of git-format-patch(1).
Gnus
----
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.
-
-
-KMail
------
-
-This should help you to submit patches inline using KMail.
-
-1) Prepare the patch as a text file.
-
-2) Click on New Mail.
-
-3) Go under "Options" in the Composer window and be sure that
-"Word wrap" is not set.
-
-4) Use Message -> Insert file... and insert the patch.
-
-5) Back in the compose window: add whatever other text you wish to the
-message, complete the addressing and subject fields, and press send.
-
-
-Gmail
------
-
-GMail does not appear to have any way to turn off line wrapping in the web
-interface, so this will mangle any emails that you send. You can however
-use any IMAP email client to connect to the google imap server, and forward
-the emails through that. Just make sure to disable line wrapping in that
-email client. Alternatively, use "git send-email" instead.
-
-Submitting properly formatted patches via Gmail is simple now that
-IMAP support is available. First, edit your ~/.gitconfig to specify your
-account settings:
-
-[imap]
- folder = "[Gmail]/Drafts"
- host = imaps://imap.gmail.com
- user = user@gmail.com
- pass = p4ssw0rd
- port = 993
- sslverify = false
-
-You might need to instead use: folder = "[Google Mail]/Drafts" if you get an error
-that the "Folder doesn't exist".
-
-Next, ensure that your Gmail settings are correct. In "Settings" the
-"Use Unicode (UTF-8) encoding for outgoing messages" should be checked.
-
-Once your commits are ready to send to the mailing list, run the following
-command to send the patch emails to your Gmail Drafts folder.
-
- $ git format-patch -M --stdout origin/master | git imap-send
-
-Go to your Gmail account, open the Drafts folder, find the patch email, fill
-in the To: and CC: fields and send away!
-