Clarify commit message format in contributing guide
RELEASE_NOTES=n/a
@@ -33,9 +33,16 @@ will try to clarify it.
* Add tests relevant to the fixed bug or new feature.
-* Add a [DCO](https://developercertificate.org/) / `Signed-off-by` line in any commit message.
+* Commit messages must contain both a [Developer Certificate of Origin](https://developercertificate.org/) / `Signed-off-by` line and a `RELEASE_NOTES=` entry, for example:
+
+ One line description of commit
+
+ More detailed description of commit, if needed.
+
+ RELEASE_NOTES=Description for release notes, or n/a if trivial.
+
+ Signed-off-by: Your Name <your@email.com>
-* Add a RELEASE_NOTES entry in every commit. Set it to n/a for minor changes that are not noteworthy for the changelog.
## Building & Testing
