在Go中强制指定导入路径

Question

New Go programmer here -- apologies if this is well worn territory, but my google searching hasn't turned up the answer I'm looking for.

Short Version: Can I, as a programmer external to the core Go project, force my packages to be imported with a specific name. If so, how?

Long Version: I recently tried to install the bcrypt package from the following GitHub repository, with the following go get

go get github.com/golang/crypto

The package downloaded correctly into my workspace, but when I tried to import it, I got the following error

$ go run main.go main.go:10:2: code in directory /path/to/go/src/github.com/golang/crypto/bcrypt expects import "golang.org/x/crypto/bcrypt"

i.e. something told Go this package was supposed to be imported with golang.org/x/crypto/bcrypt. This tipped me off that what I actually wanted was

go get golang.org/x/crypto/bcrypt

I'd like to do something similar in my own packages — is this functionality built into Go packaging? Or are the authors of crypto/bcrypt doing something at runtime to detect and reject invalid package import names?

Answer 1

Yes it's built in, I can't seem to find the implementation document (it's a relatively new feature in 1.5 or 1.6) however the syntax is:

package name // import "your-custom-path"

Example: https://github.com/golang/crypto/blob/master/bcrypt/bcrypt.go#L7

// edit

The design document for this feature is https://docs.google.com/document/d/1jVFkZTcYbNLaTxXD9OcGfn7vYv5hWtPx9--lTx1gPMs/edit

// edit

@JimB pointed out to https://golang.org/cmd/go/#hdr-Import_path_checking, and in the go1.4 release notes: https://golang.org/doc/go1.4#canonicalimports