solc: handle conflicting <file>/<contract name> pairs properly

[mattsse]

as highlighted here foundry-rs/foundry#1488

when emitting duplicated file + contract name pairs we end up overwriting them.

This is a scenario I did not anticipate when implementing the output handler and a limitation of the current layout file/contract-name.sol

we handle multiple versions with a version suffix in the file name.

if there are multiple file+name pairs it's guaranteed that the file is in another folder, meaning parent(file) is always unique. so perhaps if there are conflicts, we add the parent(file)|project roo to the output path.

either has out/parent(file)/file/contract.sol

[gakonst]

I would have expected this to be an anti pattern..agree it's an edge case we hadn't considered.

I think we end up having to add directory nesting e.g. out/inner/a.json & out/a.json next to each other? But maybe we only "unflatten" the artifacts that are conflicting?

[onbjerg]

Artifacts are in out/<filename>/<contract>.json, so if you have something like:

src/a/Token.sol
src/b/Token.sol

and both of them have a similar named contract (e.g. Token), then you'd have a conflict in the out directory, more specifically for this example, both would be trying to write to out/Token.sol/Token.json. Doesn't happen often I think, but does happen sometimes - I can imagine this is "worse" for us because dependencies might have contracts/file names similar to yours as well