`Pkg.resolve()` not picking up changes in nested `[sources]`

[mortenpi]

I have an MWE here, in the mp/resolve branch: https://github.com/mortenpi/pkg-4197-mwe/tree/mp/resolve

It's in the README, but to recap here: PackageA depends on two [sources] deps:

• MarkdownAST directly in PackageA/Project.toml
• Example.jl via PackageB

The PackageA/Manifest.toml was created when those deps were pointing to main and master respectively. Now we have changed the revs of both to mp/try-workspace and custom_branch respectively.

If you now resolve PackageA, it only picks up the change in PackageA/Project.toml (and partially at that -- not updating git-tree-sha1?), but not in PackageB/Project.toml. The expectation is that resolve should figure out that something the the [sources] tree changed, and update the current manifest appropriately, unless that's out of scope for resolve?

The practical impact is that if you have a monorepo with a bunch of internal package deps between them, there's no good way to just bring things into consistency within [sources].

Some potentially related issues: #4157, #4086.

cc @pfitzseb FYI