Re: [PATCH v2] SubmittingPatchs: clarify choice of base and testing

>We encourage identifying what, among many topics on `next`, exact
>topics a new work depends on, instead of building directly on
>`next`.  Let's clarify this in the documentation.
>
>Developers should know what they are building on top of, and be
>aware of which part of the system is currently being worked on.
>Encouraging them to make trial merges to `next` and `seen`
>themselves will incentivize them to read others' changes and
>understand them, eventually helping the developers to coordinate
>among themselves and reviewing each others' changes.
>
>Signed-off-by: Junio C Hamano <gitster@pobox.com>
>---
> Documentation/SubmittingPatches | 53 ++++++++++++++++++++++++++++++-----------
> 1 file changed, 39 insertions(+), 14 deletions(-)
>
> * I've been trying to clear the deck, and noticed that this has
>   been untended for quite some time.  With some clarification to
>   a place I was even confused myself while responding to Fabian's
>   comments in the earlier round.
>
>diff --git c/Documentation/SubmittingPatches w/Documentation/SubmittingPatches
>index e409022d93..3c4c5d9f18 100644
>--- c/Documentation/SubmittingPatches
>+++ w/Documentation/SubmittingPatches
>@@ -19,8 +19,10 @@ change is relevant to.
>   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 `seen`, but not in `master`,
>-  base your work on the tip of that topic.
>+  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
>@@ -28,10 +30,10 @@ change is relevant to.
>   into the 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 for discussion. Before the final merge, you may have to
>-  wait until some of the dependent topics graduate to `master`, and
>-  rebase your work.
>+  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).
>
> * Some parts of the system have dedicated maintainers with their own
>   repositories (see the section "Subsystems" below).  Changes to
>@@ -71,8 +73,13 @@ Make sure that you have tests for the bug you are fixing.  See
> [[tests]]
> When adding a new feature, make sure that you have new tests to show
> the feature triggers the new behavior when it should, and to show the
>-feature does not trigger when it shouldn't.  After any code change, make
>-sure that the entire test suite passes.
>+feature does not trigger when it shouldn't.  After any code change,
>+make sure that the entire test suite passes.  When fixing a bug, make
>+sure you have new tests that breaks if somebody else breaks what you

>+fixed by accident to avoid regression.  Also, try merging your work to
>+'next' and 'seen' and make sure the tests still pass; topics by others
>+that are still in flight may have unexpected interactions with what
>+you are trying to do in your topic.
>
> Pushing to a fork of https://github.com/git/git will use their CI
> integration to test your changes on Linux, Mac and Windows. See the
>@@ -144,8 +151,21 @@ without external resources. Instead of giving a URL to a mailing list
> archive, summarize the relevant points of the discussion.
>
> [[commit-reference]]
>-If you want to reference a previous commit in the history of a stable
>-branch, use the format "abbreviated hash (subject, date)", like this:
>+
>+There are a few reasons why you may want to refer to another commit in
>+the "more stable" part of the history (i.e. on branches like `maint`,
>+`master`, and `next`):
>+
>+. A commit that introduced the root cause of a bug you are fixing.
>+
>+. A commit that introduced a feature that is what you are enhancing.

>+
>+. A commit that conflicts with your work when you made a trial merge
>+  of your work into `next` and `seen` for testing.
>+
>+When you reference a commit on a more stable branch (like `master`,
>+`maint` and `next`), use the format "abbreviated hash (subject,
>+date)", like this:
>
> ....
> 	Commit f86a374 (pack-bitmap.c: fix a memleak, 2015-03-30)
>@@ -259,9 +279,11 @@ 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.
>+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.
>+

>
> [[send-patches]]
> === Sending your patches.
>@@ -365,7 +387,10 @@ Security mailing list{security-ml-ref}.
> 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.
>+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.
>
> :current-maintainer: footnote:[The current maintainer: gitster@pobox.com]
> :git-ml: footnote:[The mailing list: git@vger.kernel.org]