Excerpts from Matthew Thode's message of 2018-03-15 10:24:10 -0500: > On 18-03-15 07:03:11, Doug Hellmann wrote: > > What I Want to Do > > ----------------- > > > > 1. Update the requirements-check test job to change the check for > > an exact match to be a check for compatibility with the > > upper-constraints.txt value. > > > > We would check the value for the dependency from upper-constraints.txt > > against the range of allowed values in the project. If the > > constraint version is compatible, the dependency range is OK. > > > > This rule means that in order to change the dependency settings > > for a project in a way that are incompatible with the constraint, > > the constraint (and probably the global requirements list) would > > have to be changed first in openstack/requirements. However, if > > the change to the dependency is still compatible with the > > constraint, no change would be needed in openstack/requirements. > > For example, if the global list constraints a library to X.Y.Z > > and a project lists X.Y.Z-2 as the minimum version but then needs > > to raise that because it needs a feature in X.Y.Z-1, it can do > > that with a single patch in-tree. > > > > I think what may be better is for global-requirements to become a > gathering place for projects that requirements watches to have their > smallest constrainted installable set defined in. > > Upper-constraints has a req of foo===2.0.3 > Project A has a req of foo>=1.0.0,!=1.6.0 > Project B has a req of foo>=1.4.0 > Global reqs would be updated with foo>=1.4.0,!=1.6.0 > Project C comes along and sets foo>=2.0.0 > Global reqs would be updated with foo>=2.0.0 > > This would make global-reqs descriptive rather than prescriptive for > versioning and would represent the 'true' version constraints of > openstack.
It sounds like you're suggesting syncing in the other direction, which could be useful. I think we can proceed with what I've described and consider the work to build what you describe as a separate project. > > > We also need to change requirements-check to look at the exclusions > > to ensure they all appear in the global-requirements.txt list > > (the local list needs to be a subset of the global list, but > > does not have to match it exactly). We can't have one project > > excluding a version that others do not, because we could then > > end up with a conflict with the upper constraints list that could > > wedge the gate as we had happen in the past. > > > > How would this happen when using constraints? A project is not allowed > to have a requirement that masks a constriant (and would be verified via > the requirements-check job). If project A excludes version X before the constraint list is updated to use it, and then project B starts trying to depend on version X, they become incompatible. We need to continue to manage our declarations of incompatible versions to ensure that the constraints list is a good list of versions to test everything under. > There's a failure mode not covered, a project could add a mask (!=) to > their requirements before we update constraints. The project that was > passing the requirements-check job would then become incompatable. This > means that the requirements-check would need to be run for each > changeset to catch this as soon as it happens, instead of running only > on requirements changes. I'm not clear on what you're describing here, but it sounds like a variation of the failure modes that would be prevented if we require exclusions to exist in the global list before they could be added to the local list. > > > We also need to verify that projects do not cap dependencies for > > the same reason. Caps prevent us from advancing to versions of > > dependencies that are "too new" and possibly incompatible. We > > can manage caps in the global requirements list, which would > > cause that list to calculate the constraints correctly. > > > > This change would immediately allow all projects currently > > following the global requirements lists to specify different > > lower bounds from that global list, as long as those lower bounds > > still allow the dependencies to be co-installable. (The upper > > bounds, managed through the upper-constraints.txt list, would > > still be built by selecting the newest compatible version because > > that is how pip's dependency resolver works.) > > > > 2. We should stop syncing dependencies by turning off the > > propose-update-requirements job entirely. > > > > Turning off the job will stop the bot from proposing more > > dependency updates to projects. > > > > As part of deleting the job we can also remove the "requirements" > > case from playbooks/proposal/propose_update.sh, since it won't > > need that logic any more. We can also remove the update-requirements > > command from the openstack/requirements repository, since that > > is the tool that generates the updated list and it won't be > > needed if we aren't proposing updates any more. > > > > 3. Remove the minimum specifications from the global requirements > > list to make clear that the global list is no longer expressing > > minimums. > > > > This clean-up step has been a bit more controversial among the > > requirements team, but I think it is a key piece. As the minimum > > versions of dependencies diverge within projects, there will no > > longer *be* a real global set of minimum values. Tracking a list of > > "highest minimums", would either require rebuilding the list from the > > settings in all projects, or requiring two patches to change the > > minimum version of a dependency within a project. > > > > Maintaining a global list of minimums also implies that we > > consider it OK to run OpenStack as a whole with that list. This > > message conflicts with the message we've been sending about the > > upper constraints list since that was established, which is that > > we have a known good list of versions and deploying all of > > OpenStack with different versions of those dependencies is > > untested. > > > > As noted above I think that gathering the min versions/maskings from > openstack projects to be valuable (especially to packagers who already > use our likely invalid values already). OK. I don't feel that strongly about the cleanup work, so if we want to keep the lower bounds in place I think that's OK. > > > After these 3 steps are done, the requirements team will continue > > to maintain the global-requirements.txt and upper-constraints.txt > > files, as before. Adding a new dependency to a project will still > > involve a review step to add it to the global list so we can monitor > > licensing, duplication, python 3 support, etc. But adjusting the > > version numbers once that dependency is in the global list will be > > easier. > > > > Thanks for writing this up, I think it looks good in general, but like > you mentioned before, there is some discussion to be had about gathering > and creating a versionspec from all of openstack for requirements. > __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev