How to submit a patch to OpenEmbedded

OpenEmbedded welcomes contributions. Before submitting a patch however there are a few things to keep in mind.

Finding the right place for your patch

OpenEmbedded is now split up into separate layers: OpenEmbedded-Core (OE-Core) which is a small set of core recipes, and other layers for recipes beyond that. For most layers, patches are sent to a mailing list for review before being merged. Further information specific to the layer you're working on please see the README file in the layer.

A task-oriented guide to creating a patch

Let's say you have made a fix to a recipe, you've tested that it works and you'd like to submit it for merging.

Set up git

Properly configuring git (using tekkub@gmail.com as an example user)

On Debian / Ubuntu (Note: Fedora uses `yum` OpenSuse uses zypper or yast)

sudo aptitude install git-core git-email

These are important to the commit meta-data

git config --global user.name "Tekkub"
git config --global user.email "tekkub@gmail.com"

Any Google Apps account

git config --global sendemail.smtpserver smtp.gmail.com
git config --global sendemail.smtpserverport 587
git config --global sendemail.smtpencryption tls
git config --global sendemail.smtpuser tekkupl@gmail.com

You can use the --envelope-sender option to have the email appear to from the address you are subscribed to the list. You will need to use the Accounts and import tab ender the gmail settings tab. Use the Send mail ass selection to address you want to send email from.

Subscribe to the mailing list

You need to subscribe to the appropriate mailing-list in order to be able to send your patch(es) there; for patches against OE-Core the mailing list is openembedded-core@lists.openembedded.org and for patches against meta-oe and many other layers the list is openembedded-devel@lists.openembedded.org. See Mailing lists for subscription and further details.

Committing your patch

Commit with a concise and descriptive message - one that explains your changes in a way others get a short overview without looking at the code.

cd oe-core/ # or whereever you keep your clone of the repo
git add meta/recipes-devtools/flex
git commit -s # don't use the -m option but include my signature

   flex: backport Debian patches to fix generated code warnings
   
   The generated parser had warnings regarding signess and return check
   which makes Linux Kernel's perf tool from 3.4 release to fail without
   those patches.

All commit messages must include Signed-off-by (-s option to commit as above). For more guidelines on messages please see Commit Patch Message Guidelines.

Sending patches

There are two possible methods for submitting patches. Either one is acceptable; for a series containing a number of patches the pull request method is preferred although not mandatory.

Sending using git-send-email

To send just the top commit on your current branch (substitute mailing list address as appropriate):

git send-email --to=openembedded-core@lists.openembedded.org --confirm=always -1

For multiple commits you can substitute -1 above with -N (where N is the number of commits) or specify a revision before which to start e.g. HEAD~3, master etc.

Note: in either case if you are submitting a patch for meta-oe or any layer other than OE-Core, please add the appopriate prefix so that it is clear which layer the patch is intended to be applied to:

--subject-prefix="meta-oe][PATCH"

Please substitute "PATCH" with "PATCH v2" if you are submitting a revised version after addressing feedback (or v3, v4 etc.)

Sending via a pull request

Alternatively, for larger patch series it is preferable to send a pull request. This involves making a local branch on top of the master branch for your changes, pushing this branch to an accessible repository and then using the create-pull-request and send-pull-request scripts to create and send a patch series with a link to the branch for review.

Run scripts/create-pull-request and scripts/send-pull-request to get help on how to use these.

This section needs a little further expansion. - PaulEggleton 11:06, 7 November 2012 (UTC)

Community review

Your patch will be sent to the mailing list and should be immediately visible on http://patches.openembedded.org/

If you get feedback in reply to your patch, you should make changes according to the feedback and submit the next version. Please remember to use --subject-prefix="PATCH v2", v3, v4 etc. to mark the patch iteration.

If your patch has not had any feedback after a few days it may have been missed or the appropriate reviewers may not currently be around; it is perfectly fine to reply to it yourself with a "ping" / reminder request for feedback.

Appendix

Steps for people which don't have SMTP access for git

Patches should not be sent as attachment but inline.

If you do not have SMTP access to your email account you have two options:

1. Use a different account (e.g. gmail). you can make one especially for this. Note that the account may differ from the one in signed-off (although that is inconvenient)

2. Just include the patch in the body of your email. Make sure you use an email client that does not touch the message (turn spaces in tabs, wrap lines etc etc).

A good mail client to do so is pine (or alpine) or mutt. For more information refer to Documentation/email-clients.txt in linux kernel sources [1].