go-spew fails with withmock utility - UnsafeDisabled redeclared in this block

[aanm]

$ withmock go test
ERROR: Failed to install 'github.com/project/db': exit status 2
output:
# github.com/davecgh/go-spew/spew
../../../github.com/davecgh/go-spew/spew/bypasssafe.go:8: UnsafeDisabled redeclared in this block
        previous declaration at ../../../github.com/davecgh/go-spew/spew/bypass.go:11
../../../github.com/davecgh/go-spew/spew/bypasssafe.go:11: unsafeReflectValue redeclared in this block
        previous declaration at ../../../github.com/davecgh/go-spew/spew/bypass.go:57

More info: davecgh/go-spew#39

[davecgh]

I commented on the linked issue, but I'll post it here too for visibility.

My guess based on the error message is that this project is incorrectly ignoring the build tags. Spew uses build tags to allow different compile time behavior for the constants in question.

In particular:
bypass.go has // +build !appengine,!disableunsafe
bypasssafe.go has // +build appengine disableunsafe.

The error message clearly shows that both files are incorrectly being compiled.