[PATCH v2 3/3] b4: introduce configuration for the Git project

From: Patrick Steinhardt <ps@pks.im>
Date: Jun 3, 2026, 06:59 UTC
Message-ID: <20260603-pks-b4-v2-3-a8aea0aa2c23@pks.im>
In-Reply-To: <20260603-pks-b4-v2-0-a8aea0aa2c23@pks.im>

We're about to extend our documentation to recommend b4 for sending patch series to the mailing list. Prepare for this by introducing a b4 configuration so that the tool knows to honor our preferences. For now, this configuration does two things:

  - It configures "send-same-thread = shallow", which tells b4 to always
    send subsequent versions of the same patch series as a reply to the
    cover letter of the first version.

  - It configures "prep-cover-template", which tells b4 to use a custom
    template for the cover letter. The most important change compared to
    the default template is that our custom template also includes a
    range-diff.

There's potentially more things that we may want to configure going forward, like for example auto-configuration of folks to Cc on certain patches. But these two tweaks feel like a good place to start.

Note that these values only serve as defaults, and users may want to tweak those defaults based on their own preference. Luckily, users can do that without having to touch `.b4-config` at all, as b4 allows them to override values via Git configuration:

    ```
    $ git config set b4.prep-cover-template /does/not/exist
    $ b4 send --dry-run
    ERROR: prep-cover-template says to use x, but it does not exist
    ```

So this gives users an easy way to override our defaults without having to touch ".b4-config", which would dirty the tree.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 .b4-config         |  6 ++++++
 .b4-cover-template | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/.b4-config b/.b4-config
new file mode 100644
index 0000000000..fd4fb56b6d
--- /dev/null
+++ b/.b4-config
@@ -0,0 +1,6 @@
+# Note that these are default values that you can tweak via the typical
+# git-config(1) machinery. You thus shouldn't ever have to change this file.
+# See also https://b4.docs.kernel.org/en/latest/config.html.
+[b4]
+send-same-thread = shallow
+prep-cover-template = ./.b4-cover-template
diff --git a/.b4-cover-template b/.b4-cover-template
new file mode 100644
index 0000000000..ab864933b5
--- /dev/null
+++ b/.b4-cover-template
@@ -0,0 +1,11 @@
+${cover}
+
+---
+${shortlog}
+
+${diffstat}
+
+${range_diff}
+---
+base-commit: ${base_commit}
+${prerequisites}

-- 
2.54.0.1064.gd145956f57.dirty