On Wed, Jul 26, 2023 at 11:12:31AM -0400, Peter Xu wrote: > On Wed, Jul 26, 2023 at 08:21:35AM +0200, Markus Armbruster wrote: > > Peter Xu <pet...@redhat.com> writes: > > > > > Hi, Markus, > > > > > > On Tue, Jul 25, 2023 at 01:10:01PM +0200, Markus Armbruster wrote: > > > > [...] > > > > >> For better or worse, we duplicate full documentation between > > >> MigrationParameter, MigrateSetParameters, and MigrationParameters. This > > >> would be the first instance where we reference instead. I'm not opposed > > >> to use references, but if we do, I want them used consistently. > > > > > > We discussed this over the other "switchover" parameter, but that patchset > > > just stranded.. > > > > > > Perhaps I just provide a pre-requisite patch to remove all the comments in > > > MigrateSetParameters and MigrationParameters, letting them all point to > > > MigrationParameter? > > > > Simplifies maintaining the doc commments. But how does it affect the > > documentation generated from it? Better, neutral, or worse? > > Probably somewhere neutral. There are definitely benefits, shorter > > man/html page in total, and avoid accidentally different docs over the same > fields. E.g., we sometimes have different wordings for different objects: > > max-cpu-throttle > maximum cpu throttle percentage. Defaults to 99. (Since 3.1) > > max-cpu-throttle: int (optional) > maximum cpu throttle percentage. The default value is 99. > (Since 3.1) > > This one is fine, but it's just very easy to leak in something that shows > differently. It's good to provide coherent documentation for the same > fields over all three objects.
Do we have any actual problems though where the difference in docs is actively harmful ? I agree there's a possbility of the duplication being problematic, but unless its actually the case in reality, it is merely a theoretical downside. IMHO for someone consuming the docs, this patch is worse, not neutral. > > When looking at qemu-qmp-ref.7, it can be like this when we can invite the > reader to read the other section (assuming we only keep MigrationParameter > to keep the documentations): > > MigrationParameters (Object) > > The object structure to represent a list of migration parameters. > The optional members aren't actually optional. For detailed > explanation for each of the field, please refer to the documentation > of MigrationParameter. > > But the problem is we always will generate the Members entry, where now > it'll all filled up with "Not documented".. > > Members > announce-initial: int (optional) > Not documented > > announce-max: int (optional) > Not documented > > announce-rounds: int (optional) > Not documented > > [...] > > I think maybe it's better we just list the members without showing "Not > documented" every time for the other two objects. Not sure whether it's an > easy way to fix it, or is it a major issue. > > For developers, dedup the comment should always be a win, afaict. IMHO that's optimizing for the wrong people and isn't a measurable win anyway. Someone adding a new parameter can just cut+paste the same docs string in the three places. It is a cost, but it is a small one time cost, where having "not documented" is a ongoing cost for consumers of our API. I don't think the burden on QEMU maintainers adding new migration parameters is significant enough to justify ripping out our existing docs. 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 :|
