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diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 927f7329a5..d8a8caa791 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -3,45 +3,168 @@ Submitting Patches == Guidelines -Here are some guidelines for people who want to contribute their code to this -software. There is also a link:MyFirstContribution.html[step-by-step tutorial] +Here are some guidelines for contributing back to this +project. There is also a link:MyFirstContribution.html[step-by-step tutorial] available which covers many of these same guidelines. -[[base-branch]] -=== 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 other topics that are in `next`, but not in - `master`, fork a branch from the tip of `master`, merge these topics - to the branch, and work on that branch. You can remind yourself of - how you prepared the base with `git log --first-parent master..`. - -* 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. +[[patch-flow]] +=== A typical life cycle of a patch series -* In the exceptional case that a new feature depends on several topics - not in `master`, start working on `next` or `seen` privately and - send out patches only for discussion. Once your new feature starts - to stabilize, you would have to rebase it (see the "depends on other - topics" above). +To help us understand the reason behind various guidelines given later +in the document, first let's understand how the life cycle of a +typical patch series for this project goes. -* 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. +. You come up with an itch. You code it up. You do not need any + pre-authorization from the project to do so. ++ +Your patches will be reviewed by other contributors on the mailing +list, and the reviews will be done to assess the merit of various +things, like the general idea behind your patch (including "is it +solving a problem worth solving in the first place?"), the reason +behind the design of the solution, and the actual implementation. +The guidelines given here are there to help your patches by making +them easier to understand by the reviewers. + +. You send the patches to the list and cc people who may need to know + about the change. Your goal is *not* necessarily to convince others + that what you are building is good. Your goal is to get help in + coming up with a solution for the "itch" that is better than what + you can build alone. ++ +The people who may need to know are the ones who worked on the code +you are touching. These people happen to be the ones who are +most likely to be knowledgeable enough to help you, but +they have no obligation to help you (i.e. you ask them for help, +you don't demand). +git log -p {litdd} _$area_you_are_modifying_+ would +help you find out who they are. -To find the tip of a topic branch, run `git log --first-parent -master..seen` and look for the merge commit. The second parent of this -commit is the tip of the topic branch. +. You get comments and suggestions for improvements. You may even get + them in an "on top of your change" patch form. You are expected to + respond to them with "Reply-All" on the mailing list, while taking + them into account while preparing an updated set of patches. + +. Polish, refine, and re-send your patches to the list and to the people + who spent their time to improve your patch. Go back to step (2). + +. While the above iterations improve your patches, the maintainer may + pick the patches up from the list and queue them to the `seen` + branch, in order to make it easier for people to play with it + without having to pick up and apply the patches to their trees + themselves. Being in `seen` has no other meaning. Specifically, it + does not mean the patch was "accepted" in any way. + +. When the discussion reaches a consensus that the latest iteration of + the patches are in good enough shape, the maintainer includes the + topic in the "What's cooking" report that are sent out a few times a + week to the mailing list, marked as "Will merge to 'next'." This + decision is primarily made by the maintainer with help from those + who participated in the review discussion. + +. After the patches are merged to the 'next' branch, the discussion + can still continue to further improve them by adding more patches on + top, but by the time a topic gets merged to 'next', it is expected + that everybody agrees that the scope and the basic direction of the + topic are appropriate, so such an incremental updates are limited to + small corrections and polishing. After a topic cooks for some time + (like 7 calendar days) in 'next' without needing further tweaks on + top, it gets merged to the 'master' branch and wait to become part + of the next major release. + +In the following sections, many techniques and conventions are listed +to help your patches get reviewed effectively in such a life cycle. + + +[[choose-starting-point]] +=== Choose a starting point. + +As a preliminary step, you must first choose a starting point for your +work. Typically this means choosing a branch, although technically +speaking it is actually a particular commit (typically the HEAD, or tip, +of the branch). + +There are several important branches to be aware of. Namely, there are +four integration branches as discussed in linkgit:gitworkflows[7]: + +* maint +* master +* next +* seen + +The branches lower on the list are typically descendants of the ones +that come before it. For example, `maint` is an "older" branch than +`master` because `master` usually has patches (commits) on top of +`maint`. + +There are also "topic" branches, which contain work from other +contributors. Topic branches are created by the Git maintainer (in +their fork) to organize the current set of incoming contributions on +the mailing list, and are itemized in the regular "What's cooking in +git.git" announcements. To find the tip of a topic branch, run `git log +--first-parent master..seen` and look for the merge commit. The second +parent of this commit is the tip of the topic branch. + +There is one guiding principle for choosing the right starting point: in +general, always base your work on the oldest integration branch that +your change is relevant to (see "Merge upwards" in +linkgit:gitworkflows[7]). What this principle means is that for the +vast majority of cases, the starting point for new work should be the +latest HEAD commit of `maint` or `master` based on the following cases: + +* If you are fixing bugs in the released version, use `maint` as the + starting point (which may mean you have to fix things without using + new API features on the cutting edge that recently appeared in + `master` but were not available in the released version). + +* Otherwise (such as if you are adding new features) use `master`. + + +NOTE: In exceptional cases, a bug that was introduced in an old +version may have to be fixed for users of releases that are much older +than the recent releases. `git describe --contains X` may describe +`X` as `v2.30.0-rc2-gXXXXXX` for the commit `X` that introduced the +bug, and the bug may be so high-impact that we may need to issue a new +maintenance release for Git 2.30.x series, when "Git 2.41.0" is the +current release. In such a case, you may want to use the tip of the +maintenance branch for the 2.30.x series, which may be available in the +`maint-2.30` branch in https://github.com/gitster/git[the maintainer's +"broken out" repo]. + +This also means that `next` or `seen` are inappropriate starting points +for your work, if you want your work to have a realistic chance of +graduating to `master`. They are simply not designed to be used as a +base for new work; they are only there to make sure that topics in +flight work well together. This is why both `next` and `seen` are +frequently re-integrated with incoming patches on the mailing list and +force-pushed to replace previous versions of themselves. A topic that is +literally built on top of `next` cannot be merged to `master` without +dragging in all the other topics in `next`, some of which may not be +ready. + +For example, if you are making tree-wide changes, while somebody else is +also making their own tree-wide changes, your work may have severe +overlap with the other person's work. This situation may tempt you to +use `next` as your starting point (because it would have the other +person's work included in it), but doing so would mean you'll not only +depend on the other person's work, but all the other random things from +other contributors that are already integrated into `next`. And as soon +as `next` is updated with a new version, all of your work will need to +be rebased anyway in order for them to be cleanly applied by the +maintainer. + +Under truly exceptional circumstances where you absolutely must depend +on a select few topic branches that are already in `next` but not in +`master`, you may want to create your own custom base-branch by forking +`master` and merging the required topic branches into it. You could then +work on top of this base-branch. But keep in mind that this base-branch +would only be known privately to you. So when you are ready to send +your patches to the list, be sure to communicate how you created it in +your cover letter. This critical piece of information would allow +others to recreate your base-branch on their end in order for them to +try out your work. + +Finally, note that some parts of the system have dedicated maintainers +with their own separate source code repositories (see the section +"Subsystems" below). [[separate-commits]] === Make separate commits for logically separate changes. @@ -136,8 +259,9 @@ reasons: which case, they can explain why they extend your code to cover files, too). -The goal of your log message is to convey the _why_ behind your -change to help future developers. +The goal of your log message is to convey the _why_ behind your change +to help future developers. The reviewers will also make sure that +your proposed log message will serve this purpose well. The first line of the commit message should be a short description (50 characters is the soft limit, see DISCUSSION in linkgit:git-commit[1]), @@ -210,7 +334,7 @@ date)", like this: noticed that ... .... -The "Copy commit summary" command of gitk can be used to obtain this +The "Copy commit reference" command of gitk can be used to obtain this format (with the subject enclosed in a pair of double-quotes), or this invocation of `git show`: @@ -299,9 +423,21 @@ If you like, you can put extra tags at the end: patch after a detailed analysis. . `Tested-by:` is used to indicate that the person applied the patch and found it 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:". +. `Co-authored-by:` is used to indicate that people exchanged drafts + of a patch before submitting it. +. `Helped-by:` is used to credit someone who suggested ideas for + changes without providing the precise changes in patch form. +. `Mentored-by:` is used to credit someone with helping develop a + patch as part of a mentorship program (e.g., GSoC or Outreachy). +. `Suggested-by:` is used to credit someone with suggesting the idea + for a patch. + +While you can also create your own trailer if the situation warrants it, we +encourage you to instead use one of the common trailers in this project +highlighted above. + +Only capitalize the very first letter of tags, i.e. favor +"Signed-off-by" over "Signed-Off-By" and "Acked-by:" over "Acked-By". [[git-tools]] === Generate your patch using Git tools out of your commits. @@ -317,25 +453,68 @@ 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 base you -have chosen in the "Decide what to base your work on" section, -and unless it targets the `master` branch (which is the default), -mark your patches as such. +sending out, please make sure it cleanly applies to the starting point you +have chosen in the "Choose a starting point" section. + +NOTE: From the perspective of those reviewing your patch, the `master` +branch is the default expected starting point. So if you have chosen a +different starting point, please communicate this choice in your cover +letter. [[send-patches]] === Sending your patches. +==== Choosing your reviewers + :security-ml: footnoteref:[security-ml,The Git Security mailing list: git-security@googlegroups.com] -Before sending any patches, please note that patches that may be +NOTE: Patches that may be security relevant should be submitted privately to the Git Security mailing list{security-ml}, instead of the public mailing list. -Learn to use format-patch and send-email if possible. These commands +:contrib-scripts: footnoteref:[contrib-scripts,Scripts under `contrib/` are + +not part of the core `git` binary and must be called directly. Clone the Git + +codebase and run `perl contrib/contacts/git-contacts`.] + +Send your patch with "To:" set to the mailing list, with "cc:" listing +people who are involved in the area you are touching (the `git-contacts` +script in `contrib/contacts/`{contrib-scripts} can help to +identify them), to solicit comments and reviews. Also, when you made +trial merges of your topic to `next` and `seen`, you may have noticed +work by others conflicting with your changes. There is a good possibility +that these people may know the area you are touching well. + +If you are using `send-email`, you can feed it the output of `git-contacts` like +this: + +.... + git send-email --cc-cmd='perl contrib/contacts/git-contacts' feature/*.patch +.... + +:current-maintainer: footnote:[The current maintainer: gitster@pobox.com] +:git-ml: footnote:[The mailing list: git@vger.kernel.org] + +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{current-maintainer} +and "cc:" the list{git-ml} for inclusion. This is especially relevant +when the maintainer did not heavily participate in the discussion and +instead left the review to trusted others. + +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, and "cc:" them when sending such a final version for inclusion. + +==== `format-patch` and `send-email` + +Learn to use `format-patch` and `send-email` if possible. These commands are optimized for the workflow of sending patches, avoiding many ways -your existing e-mail client that is optimized for "multipart/*" mime -type e-mails to corrupt and render your patches unusable. +your existing e-mail client (often optimized for "multipart/*" MIME +type e-mails) might render your patches unusable. + +NOTE: Here we outline the procedure using `format-patch` and +`send-email`, but you can instead use GitGitGadget to send in your +patches (see link:MyFirstContribution.html[MyFirstContribution]). People on the Git mailing list need to be able to read and comment on the changes you are submitting. It is important for @@ -344,10 +523,12 @@ e-mail tools, so that they may comment on specific portions of your code. For this reason, each patch should be submitted "inline" in a separate message. -Multiple related patches should be grouped into their own e-mail -thread to help readers find all parts of the series. To that end, -send them as replies to either an additional "cover letter" message -(see below), the first patch, or the respective preceding patch. +All subsequent versions of a patch series and other related patches should be +grouped into their own e-mail thread to help readers find all parts of the +series. To that end, send them as replies to either an additional "cover +letter" message (see below), the first patch, or the respective preceding patch. +Here is a link:MyFirstContribution.html#v2-git-send-email[step-by-step guide] on +how to submit updated versions of a patch series. If your log message (including your name on the `Signed-off-by` trailer) is not writable in ASCII, make sure that @@ -388,6 +569,18 @@ an explanation of changes between each iteration can be kept in Git-notes and inserted automatically following the three-dash line via `git format-patch --notes`. +[[the-topic-summary]] +*This is EXPERIMENTAL*. + +When sending a topic, you can propose a one-paragraph summary that +should appear in the "What's cooking" report when it is picked up to +explain the topic. If you choose to do so, please write a 2-5 line +paragraph that will fit well in our release notes (see many bulleted +entries in the Documentation/RelNotes/* files for examples), and make +it the first paragraph of the cover letter. For a single-patch +series, use the space between the three-dash line and the diffstat, as +described earlier. + [[attachment]] 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 @@ -415,49 +608,100 @@ patch, format it as "multipart/signed", not a text/plain message that starts with `-----BEGIN PGP SIGNED MESSAGE-----`. That is not a text/plain, it's something else. -:security-ml-ref: footnoteref:[security-ml] +=== Handling Conflicts and Iterating Patches -As mentioned at the beginning of the section, patches that may be -security relevant should not be submitted to the public mailing list -mentioned below, but should instead be sent privately to the Git -Security mailing list{security-ml-ref}. +When revising changes made to your patches, it's important to +acknowledge the possibility of conflicts with other ongoing topics. To +navigate these potential conflicts effectively, follow the recommended +steps outlined below: -Send your patch with "To:" set to the mailing list, with "cc:" listing -people who are involved in the area you are touching (the `git -contacts` command in `contrib/contacts/` can help to -identify them), to solicit comments and reviews. Also, when you made -trial merges of your topic to `next` and `seen`, you may have noticed -work by others conflicting with your changes. There is a good possibility -that these people may know the area you are touching well. +. Build on a suitable base branch, see the <<choose-starting-point, section above>>, +and format-patch the series. If you are doing "rebase -i" in-place to +update from the previous round, this will reuse the previous base so +(2) and (3) may become trivial. -:current-maintainer: footnote:[The current maintainer: gitster@pobox.com] -:git-ml: footnote:[The mailing list: git@vger.kernel.org] +. Find the base of where the last round was queued ++ + $ mine='kn/ref-transaction-symref' + $ git checkout "origin/seen^{/^Merge branch '$mine'}...master" -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{current-maintainer} -and "cc:" the list{git-ml} for inclusion. This is especially relevant -when the maintainer did not heavily participate in the discussion and -instead left the review to trusted others. +. Apply your format-patch result. There are two cases +.. Things apply cleanly and tests fine. Go to (4). +.. Things apply cleanly but does not build or test fails, or things do +not apply cleanly. ++ +In the latter case, you have textual or semantic conflicts coming from +the difference between the old base and the base you used to build in +(1). Identify what caused the breakages (e.g., a topic or two may have +merged since the base used by (2) until the base used by (1)). ++ +Check out the latest 'origin/master' (which may be newer than the base +used by (2)), "merge --no-ff" the topics you newly depend on in there, +and use the result of the merge(s) as the base, rebuild the series and +test again. Run format-patch from the last such merges to the tip of +your topic. If you did ++ + $ git checkout origin/master + $ git merge --no-ff --into-name kn/ref-transaction-symref fo/obar + $ git merge --no-ff --into-name kn/ref-transaction-symref ba/zqux + ... rebuild the topic ... ++ +Then you'd just format your topic above these "preparing the ground" +merges, e.g. ++ + $ git format-patch "HEAD^{/^Merge branch 'ba/zqux'}"..HEAD ++ +Do not forget to write in the cover letter you did this, including the +topics you have in your base on top of 'master'. Then go to (4). -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, and "cc:" them when sending such a final version for inclusion. +. Make a trial merge of your topic into 'next' and 'seen', e.g. ++ + $ git checkout --detach 'origin/seen' + $ git revert -m 1 <the merge of the previous iteration into seen> + $ git merge kn/ref-transaction-symref ++ +The "revert" is needed if the previous iteration of your topic is +already in 'seen' (like in this case). You could choose to rebuild +master..origin/seen from scratch while excluding your previous +iteration, which may emulate what happens on the maintainers end more +closely. ++ +This trial merge may conflict. It is primarily to see what conflicts +_other_ topics may have with your topic. In other words, you do not +have to depend on it to make your topic work on 'master'. It may +become the job of the other topic owners to resolve conflicts if your +topic goes to 'next' before theirs. ++ +Make a note on what conflict you saw in the cover letter. You do not +necessarily have to resolve them, but it would be a good opportunity to +learn what others are doing in related areas. ++ + $ git checkout --detach 'origin/next' + $ git merge kn/ref-transaction-symref ++ +This is to see what conflicts your topic has with other topics that are +already cooking. This should not conflict if (3)-2 prepared a base on +top of updated master plus dependent topics taken from 'next'. Unless +the context is severe (one way to tell is try the same trial merge with +your old iteration, which may conflict in a similar way), expect that it +will be handled on maintainers end (if it gets unmanageable, I'll ask to +rebase when I receive your patches). == 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 Pratyush Yadav: +- `git-gui/` comes from git-gui project, maintained by Johannes Sixt: - https://github.com/prati0100/git-gui.git + https://github.com/j6t/git-gui - `gitk-git/` comes from Paul Mackerras's gitk project: git://git.ozlabs.org/~paulus/gitk - Those who are interested in improve gitk can volunteer to help Paul - in maintaining it cf. <YntxL/fTplFm8lr6@cleo>. + Those who are interested in improving gitk can volunteer to help Paul + maintain it, cf. <YntxL/fTplFm8lr6@cleo>. - `po/` comes from the localization coordinator, Jiang Xin: @@ -465,54 +709,12 @@ repositories. Patches to these parts should be based on their trees. -[[patch-flow]] -== An ideal patch flow - -Here is an ideal patch flow for this project the current maintainer -suggests to the contributors: - -. You come up with an itch. You code it up. - -. Send it to the list and cc people who may need to know about - the change. -+ -The people who may need to know are the ones whose code you -are butchering. These people happen to be the ones who are -most likely to be knowledgeable enough to help you, but -they have no obligation to help you (i.e. you ask for help, -don't demand). +git log -p {litdd} _$area_you_are_modifying_+ would -help you find out who they are. - -. You get comments and suggestions for improvements. You may - even get them in an "on top of your change" patch form. - -. Polish, refine, and re-send to the list and the people who - spend their time to improve your patch. Go back to step (2). - -. The list forms consensus that the last round of your patch is - good. Send it to the maintainer and cc the list. - -. A topic branch is created with the patch and is merged to `next`, - and cooked further and eventually graduates to `master`. - -In any time between the (2)-(3) cycle, the maintainer may pick it up -from the list and queue it to `seen`, in order to make it easier for -people play with it without having to pick up and apply the patch to -their trees themselves. - -[[patch-status]] -== Know the status of your patch after submission +- The "Git documentation translations" project, led by Jean-Noël + Avila, translates our documentation pages. Their work products are + maintained separately from this project, not as part of our tree: -* You can use Git itself to find out when your patch is merged in - master. `git pull --rebase` will automatically skip already-applied - patches, and will let you know. This works only if you rebase on top - of the branch in which your patch has been merged (i.e. it will not - tell you if your patch is merged in `seen` if you rebase on top of - master). + https://github.com/jnavila/git-manpages-l10n/ -* Read the Git mailing list, the maintainer regularly posts messages - entitled "What's cooking in git.git" and "What's in git.git" giving - the status of various proposed changes. == GitHub CI[[GHCI]] @@ -531,11 +733,12 @@ After the initial setup, CI will run whenever you push new changes to your fork of Git on GitHub. You can monitor the test state of all your branches here: `https://github.com/<Your GitHub handle>/git/actions/workflows/main.yml` -If a branch did not pass all test cases then it is marked with a red -cross. In that case you can click on the failing job and navigate to -"ci/run-build-and-tests.sh" and/or "ci/print-test-failures.sh". You -can also download "Artifacts" which are tarred (or zipped) archives -with test data relevant for debugging. +If a branch does not pass all test cases then it will be marked with a +red +x+, instead of a green check. In that case, you can click on the +failing job and navigate to "ci/run-build-and-tests.sh" and/or +"ci/print-test-failures.sh". You can also download "Artifacts" which +are zip archives containing tarred (or zipped) archives with test data +relevant for debugging. Then fix the problem and push your fix to your GitHub fork. This will trigger a new CI build to ensure all tests pass. @@ -543,7 +746,7 @@ trigger a new CI build to ensure all tests pass. [[mua]] == MUA specific hints -Some of patches I receive or pick up from the list share common +Some of the 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. @@ -627,7 +830,7 @@ 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 +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 |