Oh, hm, yeah I could see that happening. I’d recommend going with stripping. It’ll look something like this:

stripped_sources = await Get(Digest, RemovePrefix(sources.snapshot.digest, "a/b/c")
result = await Get(ProcessResult, PexProcess(.., input_digest=stripped_sources)

You can add back a prefix on the resulting digest, too.

await Get(Digest, AddPrefix(result.output_digest, "a/b/c")