Agreed to both points. I’m conflicted on whether to use write or materialize. FWIT, if we stick with materialize, we can rename

DirectoryToMaterialize

to

MaterializeDigest

. Or, actually, maybe

MaterializeToBuildRoot

WriteToBuildRoot

? It’s long enough that we discourage using it. And it resolves one of the biggest confusions: you can only write to the build root, not any arbitrary place