So changing the precedence of the MetaPathFinder to win over standard path imports has some nasty consequences...

There some specs and applications that expect the order of sys.path entries to be respected over anything else...

This means that this PR is not applicable.

I suspect that the best way forward with editable installs is to use PathEntryFinders instead and mimic the way zipimporter works... This is discussed in pfmoore/editables#21, however it is something complex and require some time to implement (so postponed until I or other member of the community has the time to investigate).

Sorry for posting on such an old topic. This seems to be the only topic that really applies.

Here you tried to put the editable installations first, but what if we just move it to the before-last one and make sure the local importer is last, as such?
astral-sh/uv#1708 (comment)

Wouldn't that work?
The current precedency is not particularly kind for monorepos. I wonder if any of them use the non-legacy version

what if we just move it to the before-last on

Isn't that exactly the same thing as inserting before PathFinder (with the difference that using PathFinder as a reference is better than relying on arbitrary indexes, like -1 or -2, that can change in runtime).

In this PR we tried inserting before PathFinder, but as the comments above says it doesn't work (not because it is conceptually wrong, but because some tools are not prepared to deal with it).