cmd/go: internal package import not allowed from within the standard library

[FiloSottile]

For a new version of CL 703015 I tried importing internal/syscall/windows from the new crypto/internal/fips140/entropy package.

I expected that to work according to https://pkg.go.dev/cmd/go#hdr-Internal_Directories, since crypto/internal/fips140/entropy is in the tree rooted at the parent of internal/, which should be the whole standard library.

Instead (building with GOOS=windows):

# crypto/internal/fips140test
package crypto/internal/fips140test (test)
        imports crypto/internal/fips140/entropy
        src/crypto/internal/fips140/entropy/now_noasm.go:10:2: use of internal package internal/syscall/windows not allowed
FAIL    crypto/internal/fips140test [setup failed]
FAIL

/cc @golang/compiler

[cherrymui]

cc @golang/command-line

[gabyhelp]

Related Issues

• cmd/go/pkg.go: `func disallowInternal` does not permit import from code rooted **below** the parent of the “internal” directory. #21215 (closed)
• cmd/go: can't use internal package in a module #27022 (closed)

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[FiloSottile]

Bizarrely, I moved the import to crypto/internal/fips140deps/time and it works there. Maybe something due to the fips140 import paths rewrites, in which case it would still be a bug but pretty low priority (since we do try to intermediate all internal imports via crypto/internal/fips140deps to avoid fossilizing them).