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authorKonstantin Ryabitsev <konstantin@linuxfoundation.org>2019-10-30 17:00:50 +0300
committerJonathan Corbet <corbet@lwn.net>2019-11-07 23:17:25 +0300
commite8686a40a32aee572b87552b0835922a1e47bd87 (patch)
tree518b91e3abbea7e9d34b67ff33b2eb5c8ae63533 /Documentation/process
parent36bc683dde0af61c6e677e5832ad4380771380d3 (diff)
downloadlinux-e8686a40a32aee572b87552b0835922a1e47bd87.tar.xz
docs: process: Add base-commit trailer usage
One of the recurring complaints from both maintainers and CI system operators is that performing git-am on received patches is difficult without knowing the parent object in the git history on which the patches are based. Without this information, there is a high likelihood that git-am will fail due to conflicts, which is particularly frustrating to CI operators. Git versions starting with v2.9.0 are able to automatically include base-commit information using the --base flag of git-format-patch. Document this usage in process/submitting-patches, and add the rationale for its inclusion, plus instructions for those not using git on where the "base-commit:" trailer should go. Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/process')
-rw-r--r--Documentation/process/submitting-patches.rst53
1 files changed, 52 insertions, 1 deletions
diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst
index fb56297f70dc..ba5e944c7a63 100644
--- a/Documentation/process/submitting-patches.rst
+++ b/Documentation/process/submitting-patches.rst
@@ -782,7 +782,58 @@ helpful, you can use the https://lkml.kernel.org/ redirector (e.g., in
the cover email text) to link to an earlier version of the patch series.
-16) Sending ``git pull`` requests
+16) Providing base tree information
+-----------------------------------
+
+When other developers receive your patches and start the review process,
+it is often useful for them to know where in the tree history they
+should place your work. This is particularly useful for automated CI
+processes that attempt to run a series of tests in order to establish
+the quality of your submission before the maintainer starts the review.
+
+If you are using ``git format-patch`` to generate your patches, you can
+automatically include the base tree information in your submission by
+using the ``--base`` flag. The easiest and most convenient way to use
+this option is with topical branches::
+
+ $ git checkout -t -b my-topical-branch master
+ Branch 'my-topical-branch' set up to track local branch 'master'.
+ Switched to a new branch 'my-topical-branch'
+
+ [perform your edits and commits]
+
+ $ git format-patch --base=auto --cover-letter -o outgoing/ master
+ outgoing/0000-cover-letter.patch
+ outgoing/0001-First-Commit.patch
+ outgoing/...
+
+When you open ``outgoing/0000-cover-letter.patch`` for editing, you will
+notice that it will have the ``base-commit:`` trailer at the very
+bottom, which provides the reviewer and the CI tools enough information
+to properly perform ``git am`` without worrying about conflicts::
+
+ $ git checkout -b patch-review [base-commit-id]
+ Switched to a new branch 'patch-review'
+ $ git am patches.mbox
+ Applying: First Commit
+ Applying: ...
+
+Please see ``man git-format-patch`` for more information about this
+option.
+
+.. note::
+
+ The ``--base`` feature was introduced in git version 2.9.0.
+
+If you are not using git to format your patches, you can still include
+the same ``base-commit`` trailer to indicate the commit hash of the tree
+on which your work is based. You should add it either in the cover
+letter or in the first patch of the series and it should be placed
+either below the ``---`` line or at the very bottom of all other
+content, right before your email signature.
+
+
+17) Sending ``git pull`` requests
---------------------------------
If you have a series of patches, it may be most convenient to have the