Dynamic BuildRequires are not reevaulated automatically in some cases

[ignatenkobrain]

Issue Description

https://build.opensuse.org/package/show/home:ignatenkobrain:rust/rust-tera

This package, on dynamic BR generation would produce 0.8 ≤ globwalk < 0.9, but OBS still shows previous BRs.

Expected Result

Dynamic BuildRequires would be re-evaluated and build succeed.

How to Reproduce

1. Have multiple inter-dependent packages with dynamic BuildRequires
2. Update one which would break dependencies of the other
3. Update the other package which would fix the depedency
4. See that dynamic BRs are not re-evaluated on the other package

Further Information

I have updated globwalk to 0.8 almost at the same time as tera to 1.2.0 (which depends on globwalk 0.8)

cc @mlschroe @adrianschroeter

[adrianschroeter]

This is a design limitation in current implementation with dynamic buildrequires. We would need many VM startups to resolve this, just for dependency solving which is currently not wanted.

You can workaround it via "osc wipebinaries" on the unresolved packages to trigger a recalculation.

[ignatenkobrain]

@adrianschroeter I think the way this currently works is wrong. All rust-* packages have BuildRequires: rust-packaging, so only if that package is changing, you need to re-evaluate dynamic BuildRequires.

[ignatenkobrain]

And rust-packaging is changing once per few months, so this would be very rare re-calculation. Of course, each commit would need to force recalculation of specific package, but this is also not very often happening.