On Sat, Jan 27, 2024 at 10:36:24PM +0800, Zhao Liu wrote: > Hi Daniel, > > On Thu, Nov 23, 2023 at 11:40:25AM +0000, Daniel P. Berrangé wrote: > > +Multiple authorship > > +~~~~~~~~~~~~~~~~~~~ > > + > > +It is not uncommon for a patch to have contributions from multiple > > +authors. In such a scenario, a git commit will usually be expected > > +to have a ``Signed-off-by`` line for each contributor involved in > > +creatin of the patch. Some edge cases: > > + > > + * The non-primary author's contributions were so trivial that > > + they can be considered not subject to copyright. In this case > > + the secondary authors need not include a ``Signed-off-by``. > > + > > + This case most commonly applies where QEMU reviewers give short > > + snippets of code as suggested fixes to a patch. The reviewers > > + don't need to have their own ``Signed-off-by`` added unless > > + their code suggestion was unusually large. > > + > > + * Both contributors work for the same employer and the employer > > + requires copyright assignment. > > + > > + It can be said that in this case a ``Signed-off-by`` is indicating > > + that the person has permission to contributeo from their employer > > + who is the copyright holder. > > For this case, maybe it needs the "Co-developed-by"?
If you're going to go to the trouble of adding multiple tags to the commit for each author who participated, then IMHO they should all be Signed-off-by. IOW, either just have S-o-B from the main author within a company, or have S-o-B for every author. Co-developed-by doesn't have value IMHO. > > It is none the less still preferrable > > + to include a ``Signed-off-by`` for each contributor, as in some > > + countries employees are not able to assign copyright to their > > + employer, and it also covers any time invested outside working > > + hours. > > + > > +Other commit tags > > +~~~~~~~~~~~~~~~~~ > > + > > +While the ``Signed-off-by`` tag is mandatory, there are a number of > > +other tags that are commonly used during QEMU development > > + > > + * **``Reviewed-by``**: when a QEMU community member reviews a patch > > + on the mailing list, if they consider the patch acceptable, they > > + should send an email reply containing a ``Reviewed-by`` tag. > > Maybe just a question, the people should drop the Reviewed/ACKed/Tested > tags that have been obtained if he make the any code changes (including > function/variable renaming) as well as commit message changes during > the patch refresh process, am I understand correctly? ;-) It is a judgement call as to whether a Reviewed-by/etc should be kept or dropped. It depends on the scale of the changes that were made to the commit since the Reviewed-by/etc was first given. > > + NB: a subsystem maintainer sending a pull request would replace > > + their own ``Reviewed-by`` with another ``Signed-off-by`` > > + > > + * **``Acked-by``**: when a QEMU subsystem maintainer approves a patch > > + that touches their subsystem, but intends to allow a different > > + maintainer to queue it and send a pull request, they would send > > + a mail containing a ``Acked-by`` tag. > > + > > + * **``Tested-by``**: when a QEMU community member has functionally > > + tested the behaviour of the patch in some manner, they should > > + send an email reply conmtaning a ``Tested-by`` tag. > > Is there any requirement for the order of tags? > > My previous understanding was that if the Reviewed-by/Tested-by tags > were obtained by the author within his company, then those tags should > be placed before the signed-off-by of the author. If the Reviewed-by/ > Tested-by were acquired in the community, then they should be placed > after the author's signed-off-by, right? Common practice is for Signed-off-by tags to be kept in time order from earliest author to latest author / maintainer. Common case is 2 S-o-B, the first from the patch author, and the last from the sub-system maintainer who sends the pull request. For other tags I don't see any broadly acceptable pattern. Some people add Reviewed-by before the S-o-B, others add Reviewed-by after the S-o-B. Either is fine IMHO. > > +Re-starting abandoned work > > +~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +For a variety of reasons there are some patches that get submitted to > > +QEMU but never merged. An unrelated contributor may decide (months or > > +years later) to continue working from the abandoned patch and re-submit > > +it with extra changes. > > + > > +If the abandoned patch already had a ``Signed-off-by`` from the original > > +author this **must** be preserved. > > I find some people added Originally-by, e.g., 8e86851bd6b9. > > I guess if the code has been changed very significantly, or if the > original implementation has just been referenced and significantly > refactored, then Originally-by should be preferred instead of > Signed-off-by from the original author, right? If patch submitted still contains any code that can be considered copyrightable (ie anything non-trivial) from the original author, then I would expect the original authors Signed-off-by to be retained. I think the cases where it is ok to use Originally-by, without a Signed-off-by, would be exceedingly. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
