Managing a kernel patch series with b4
This is a (live-[?])blog about managing a patch series solely with b4.
It’s “live” as I’m writing this down while fumbling my way through this adventure.
No corrections other than grammer and spelling (but no guarantees for the correctness of either).
UPDATE START
After having written this Konstantin (the author of b4) pointed me to https://b4.docs.kernel.org which answers a few questions I had here.
UPDATE END
Ok, I have a xfstests patch to send.
The patch has been written and tested.
I’ve already created a branch fstests.setgid.v6.2 based on xfstests’s for-next branch.
So, first step locate the subcommand that will allow me to do something with that patch/branch.
b4 --help
That shows a subcommand prep which looks like what I would want:
> b4 prep --help
usage: b4 prep [-h] [-c | -p OUTPUT_DIR | --edit-cover | --show-revision | --force-revision N | --compare-to vN | --manual-reroll COVER_MSGID | --set-prefixes PREFIX [PREFIX ...] |
--show-info] [-n NEW_SERIES_NAME] [-f FORK_POINT] [-F MSGID] [-e ENROLL_BASE]
options:
-h, --help show this help message and exit
-c, --auto-to-cc Automatically populate cover letter trailers with To and Cc addresses
-p OUTPUT_DIR, --format-patch OUTPUT_DIR
Output prep-tracked commits as patches
--edit-cover Edit the cover letter in your defined $EDITOR (or core.editor)
--show-revision Show current series revision number
--force-revision N Force revision to be this number instead
--compare-to vN Display a range-diff to previously sent revision N
--manual-reroll COVER_MSGID
Mark current revision as sent and reroll (requires cover letter msgid)
--set-prefixes PREFIX [PREFIX ...]
Extra prefixes to add to [PATCH] (e.g.: RFC mydrv)
--show-info Show current series info in a column-parseable format
Create new branch:
Create a new branch for working on patch series
-n NEW_SERIES_NAME, --new NEW_SERIES_NAME
Create a new branch for working on a patch series
-f FORK_POINT, --fork-point FORK_POINT
When creating a new branch, use this fork point instead of HEAD
-F MSGID, --from-thread MSGID
When creating a new branch, use this thread
Enroll existing branch:
Enroll existing branch for prep work
-e ENROLL_BASE, --enroll ENROLL_BASE
Enroll current branch, using the passed tag, branch, or commit as fork base
Ok, so looks like I first need to enroll that branch.
It wants a base so I’m going to use HEAD~1 as I’m basing this on the for-next branch of xfstests:
> b4 prep -e HEAD~1
Will track 1 commits
Created the default cover letter, you can edit with --edit-cover.
So that worked. First question I have is whether I can exmatriculate a branch?
Ah, neat it seems that the cover letter is kept as an empty commit before the actual commit:
commit 416776f9204e73dfc6900c5e41a7aa47e869203a
Author: Christian Brauner <brauner@kernel.org>
AuthorDate: Tue Jan 3 15:43:06 2023 +0100
Commit: Christian Brauner (Microsoft) <brauner@kernel.org>
CommitDate: Tue Jan 3 15:43:06 2023 +0100
EDITME: cover title for fstests.setgid.v6.2
# Lines starting with # will be removed from the cover letter. You can use
# them to add notes or reminders to yourself.
EDITME: describe the purpose of this series. The information you put here
will be used by the project maintainer to make a decision whether your
patches should be reviewed, and in what priority order. Please be very
detailed and link to any relevant discussions or sites that the maintainer
can review to better understand your proposed changes. If you only have a
single patch in your series, the contents of the cover letter will be
appended to the "under-the-cut" portion of the patch.
# You can add trailers to the cover letter. Any email addresses found in
# these trailers will be added to the addresses specified/generated during
# the b4 send stage. You can also run "b4 prep --auto-to-cc" to auto-populate
# the To: and Cc: trailers based on the code being modified.
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
--- b4-submit-tracking ---
# This section is used internally by b4 prep for tracking purposes.
{
"series": {
"revision": 1,
"change-id": "20230103-fstests-setgid-v6-2-4ce5852d11e2",
"base-branch": null,
"prefixes": []
}
}
My solution so far had been to keep it as a branch description. I don’t have a strong opinion about this though I’m not sure I like the empty commit thing. But the motivation most likely is that branch descriptions aren’t kept/synced across remotes whereas an empty commit is.
In any case, I’m not concinved that my single patch needs a cover letter so I need to figure out how to get rid of it. Given that I don’t see a direct command to achieve this the first thing that comes to mind is to make the empty commit’s commit message empty. Let’s try that:
> b4 prep --edit-cover
New cover letter blank, leaving current one unchanged.
Let’s put a comment under there?
commit 8c6a27fc5b793a4a23bb9d457662ed821b5431df
Author: Christian Brauner <brauner@kernel.org>
AuthorDate: Tue Jan 3 15:43:06 2023 +0100
Commit: Christian Brauner (Microsoft) <brauner@kernel.org>
CommitDate: Tue Jan 3 15:43:06 2023 +0100
# I don't need a cover letter.
--- b4-submit-tracking ---
# This section is used internally by b4 prep for tracking purposes.
{
"series": {
"revision": 1,
"change-id": "20230103-fstests-setgid-v6-2-4ce5852d11e2",
"base-branch": null,
"prefixes": []
}
}
It seems that for the next step I might need to use b4 send. It provides
--dry-run and --reflect where the former option is pretty self-explanatory
and the latter option allow to send the patch series to myself.
Let’s try that:
> b4 send --reflect
Converted the branch to 1 messages
---
To: "Christian Brauner (Microsoft)" <brauner@kernel.org>
---
[PATCH] generic: update setgid tests
+Cc: Amir Goldstein <amir73il@gmail.com>
Zorro Lang <zlang@redhat.com>
---
Ready to:
- send the above messages to just Christian Brauner <brauner@kernel.org> (REFLECT MODE)
- with envelope-from: Christian Brauner <brauner@kernel.org>
- via SMTP server mail.kernel.org
REFLECT MODE:
The To: and Cc: headers will be fully populated, but the only
address given to the mail server for actual delivery will be
Christian Brauner <brauner@kernel.org>
Addresses in To: and Cc: headers will NOT receive this series.
Press Enter to proceed or Ctrl-C to abort
That looks good. Excellent that it points out that it will only be sent to me and no one else. I like this a lot!
Ah, that was skinny love.
Press Enter to proceed or Ctrl-C to abort
Connecting to mail.kernel.org:587
Traceback (most recent call last):
File "/home/brauner/src/git/b4/b4/command.py", line 376, in <module>
cmd()
File "/home/brauner/src/git/b4/b4/command.py", line 359, in cmd
cmdargs.func(cmdargs)
File "/home/brauner/src/git/b4/b4/command.py", line 86, in cmd_send
b4.ez.cmd_send(cmdargs)
File "/home/brauner/src/git/b4/b4/ez.py", line 1523, in cmd_send
sent = b4.send_mail(smtp, send_msgs, fromaddr=fromaddr, patatt_sign=sign,
File "/home/brauner/src/git/b4/b4/__init__.py", line 3257, in send_mail
bdata = patatt.rfc2822_sign(bdata)
AttributeError: module 'patatt' has no attribute 'rfc2822_sign'
Chances are that my patatt version is too old?
Ok, let’s try pip3 install --upgrade patatt and try this again:
> b4 send --reflect
Converted the branch to 1 messages
---
To: "Christian Brauner (Microsoft)" <brauner@kernel.org>
---
[PATCH] generic: update setgid tests
+Cc: Amir Goldstein <amir73il@gmail.com>
Zorro Lang <zlang@redhat.com>
---
Ready to:
- send the above messages to just Christian Brauner <brauner@kernel.org> (REFLECT MODE)
- with envelope-from: Christian Brauner <brauner@kernel.org>
- via SMTP server mail.kernel.org
REFLECT MODE:
The To: and Cc: headers will be fully populated, but the only
address given to the mail server for actual delivery will be
Christian Brauner <brauner@kernel.org>
Addresses in To: and Cc: headers will NOT receive this series.
Press Enter to proceed or Ctrl-C to abort
Connecting to mail.kernel.org:587
---
[PATCH] generic: update setgid tests
---
Reflected 1 messages
There we go! Let’s inspect whether the patch looks sane.
I would really appreciate if I didn’t have to carry a pointless empty commit message with the commend # I don't need a cover letter.:
commit 8c6a27fc5b793a4a23bb9d457662ed821b5431df
Author: Christian Brauner <brauner@kernel.org>
AuthorDate: Tue Jan 3 15:43:06 2023 +0100
Commit: Christian Brauner (Microsoft) <brauner@kernel.org>
CommitDate: Tue Jan 3 15:43:06 2023 +0100
# I don't need a cover letter.
--- b4-submit-tracking ---
# This section is used internally by b4 prep for tracking purposes.
{
"series": {
"revision": 1,
"change-id": "20230103-fstests-setgid-v6-2-4ce5852d11e2",
"base-branch": null,
"prefixes": []
}
}
Seems like that could be improved by at least allowing no content other than the b4-submit-tracking content in there.
Another thought, while b4 send allows to specify recipients via --to and --cc it would be neat if one could store additional recipients alongside each patch outside of trailers.
Currently I do this by tagging each commit I generate via git format-patch based on git notes which are then moved before the SUBJECT line.
For example:
From 8575998dc5ac659f9d893220372cabbbb65c323d Mon Sep 17 00:00:00 2001
From: Christian Brauner <a@b>
Date: Fri, 23 Sep 2022 10:29:39 +0200
To: A <a@a>
Cc: B <b@b>
Cc: C <c@c>
Cc: D <d@d>
Cc: E <e@e>
Subject: [PATCH v5 02/30] some: commmimt
It be excellent if that were possible.
UPDATE START
This seems possible:
What if I only have a single patch?
When you only have a single patch, the contents of the cover letter will be mixed into the “under-the-cut” portion of the patch. You can just use the cover letter for extra To/Cc trailers and changelog entries as your patch goes through revisions. If you add more commits in the future version, you can fill in the cover letter content with additional information about the intent of your entire series.
(https://b4.docs.kernel.org/en/latest/contributor/prep.html#what-if-i-only-have-a-single-patch)
UPDATE END
For the single patch I can do with just using the --to and --cc flags to b4 send.
So let’s try this but better safe than sorry and also let’s take the chance to try --dry-run:
> b4 send --cc="Amir Goldstein <amir73il@gmail.com>" --cc="Zorro Lang <zlang@redhat.com>" --to="<fstests@vger.kernel.org>" --dry-run
Converted the branch to 1 messages
--- DRYRUN: message follows ---
| From: Christian Brauner <brauner@kernel.org>
| Date: Tue, 03 Jan 2023 16:26:26 +0100
| Subject: [PATCH] generic: update setgid tests
| MIME-Version: 1.0
| Content-Type: text/plain; charset="utf-8"
| Content-Transfer-Encoding: 7bit
| Message-Id: <20230103-fstests-setgid-v6-2-v1-1-cbdbeef2411a@kernel.org>
| X-B4-Tracking: v=1; b=H4sIACJJtGMC/x2NwQqDMBAFf0X23IVkraX0V0oPMXnqgqQlG6Ug/
| ntDjzMwzEGGojB6dAcV7Gr6zg38paO4hDyDNTUmcdI773qerMKqsaHOmni/sfA1YrgPkryHUCvH
| YOCxhByX1uZtXZv8FEz6/a+er/P8AY8ALQl6AAAA
| To: fstests@vger.kernel.org
| Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org>, Zorro Lang <zlang@redhat.com>,
| Amir Goldstein <amir73il@gmail.com>
| X-Mailer: b4 0.12-dev-214b3
| X-Developer-Signature: v=1; a=openpgp-sha256; l=11235; i=brauner@kernel.org;
| h=from:subject:message-id; bh=Oi7CQzED3JPkJt0k+GEUAJ3KgV2hlR5H9UVIMTL7D54=;
| b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSRv8VRqrb5e/2BddGniFuONH66XL6oU33feadWtOWfnTmMR
| M157sqOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAi8+YzMhz+fd3m3CfdR3/fvFxy9t
| Xj36frBTq/Vgvy/isXDvRg7Gdh+J8ZvXPBu2W8mwpPd8ZbXZn3alVEZq9XiPk2YSt5yZVftLgB
| X-Developer-Key: i=brauner@kernel.org; a=openpgp;
| fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624
|
[I'm snipping the actual content as this is not of interest here.]
| ---
| base-commit: fbd489798b31e32f0eaefcd754326a06aa5b166f
| change-id: 20230103-fstests-setgid-v6-2-4ce5852d11e2
|
| Best regards,
| --
| Christian Brauner (Microsoft) <brauner@kernel.org>
--- DRYRUN: message ends ---
---
DRYRUN: Would have sent 1 messages
So let’s try this for real:
> b4 send --cc="Amir Goldstein <amir73il@gmail.com>" --cc="Zorro Lang <zlang@redhat.com>" --to="<fstests@vger.kernel.org>"
Converted the branch to 1 messages
---
To: fstests@vger.kernel.org
Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org>
Zorro Lang <zlang@redhat.com>
---
[PATCH] generic: update setgid tests
+Cc: Amir Goldstein <amir73il@gmail.com>
---
Ready to:
- send the above messages to actual listed recipients
- with envelope-from: Christian Brauner <brauner@kernel.org>
- via SMTP server mail.kernel.org
- tag and reroll the series to the next revision
Press Enter to proceed or Ctrl-C to abort
Connecting to mail.kernel.org:587
---
[PATCH] generic: update setgid tests
---
Sent 1 messages
Tagging sent/fstests.setgid.v6.2-v1
Recording series message-id in cover letter tracking
Created new revision v2
Updating cover letter with templated changelog entries.
Invoking git-filter-repo to update the cover letter.
New history written in 0.02 seconds...
Completely finished after 0.05 seconds.
Ok, let’s check my own mail whether this looks good. And yes, it does:
Date: Tue, 03 Jan 2023 16:28:20 +0100
From: Christian Brauner <brauner@kernel.org>
To: fstests@vger.kernel.org
Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org>, Zorro Lang <zlang@redhat.com>, Amir Goldstein <amir73il@gmail.com>
Subject: [PATCH] generic: update setgid tests
X-Date: Tue, 03 Jan 2023 16:28:20 +0100
X-URI: https://lore.kernel.org/fstests/20230103-fstests-setgid-v6-2-v1-1-b8972c303ebe@kernel.org