Last month, we had a Modularity Hackfest in Boston. I wrote up a hackfest report at the Community Blog[1] back then, which included several open questions related to how to handle stream and profile defaults. I'm reprinting them here on Fedora Devel for public input. == Open Questions == We had some discussions throughout the course of the hackfest that didn’t reach a clear consensus. The most contentious was around what to do about empty profile data. There are several uncommon cases that need to have clear UX decisions made around them. === A module does not have one or more of its profiles specified to be the default. === The module creator has not provided a defaults object into the YAML (in Fedora, this is done by requesting it be added by release engineering or submitting a pull request to the fedora-module-defaults repository). This may be intentional or unintentional. Fedora QA has asked us if they should be treating the lack of a defaults reference for the profile as a failure, since this is something that could be detected during post-compose testing and reported. My personal opinion on this case is that for modules in Fedora itself, we should indeed treat this as a bug and require that all modules have a defaults object that properly references a set of default profiles for any stream included in that compose. The open question here is what the DNF experience should be if dnf module install modulename:modulestream is called. The current behavior is that DNF treats this as equivalent to calling dnf module enable modulename:modulestream (it makes the contents of this module explicitly available, but installs nothing at that time. Feedback from users of the RHEL 8 Beta have indicated that this is an unexpected behavior of the install verb. They’d prefer to see DNF report an error if install is called and results in no packages being installed. In part, this is because it would be silently hiding the possibility that the defaults are missing. === A module has explicitly set one or more of its streams to have no default profiles === This is a similar case to the above, except that a conscious choice was made by the module maintainer to say that this module has no reasonable default packages that could be selected. (For example, it could be a collection of popular libraries that extend a particular programming language, but there’s no obvious subset of them that makes sense to install. It may exist and have streams solely because it needs to be kept in sync with the interpreter version.) The open question is the same as the previous one: how should dnf module install handle this case? In this particular example, it might be more acceptable that it follows the enable fallback, since the maintainer selected the lack of a profile explicitly. However, having context-sensitive differences can be difficult for people to process. === A module has a profile that contains zero RPMs === In this case, a profile definition has been made in the module metadata and it explicitly contains zero RPMs within it. Such an example might be for compatibility: the module previously provided a profile with that name that contained content, but it is no longer doing so. Retaining the name may have been done to allow existing scripts to avoid breaking. If we have a profile that contains zero packages, should it be an error if we attempt to install it? If not, what should the UX look like? [1] https://communityblog.fedoraproject.org/modularity-hackfest-march-2019/ _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
