cmd/go: modules don't support url encoded spaces

[damienfamed75]

What version of Go are you using (go version)?

$ go version
go version go1.16.1 windows/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

What did you do?

Go modules do not support the % symbol to be used in the import URL. This can appear when companies use spaces in their project names in Azure DevOps or some other git providers.

Yes, I know it's silly to have a space character, but it does happen and can make %20 in the URL unavoidable without making a new project and sometimes that's not possible.

This is already a pre-existing issue #45549

What did you expect to see?

I expected the module name to work.

What did you see instead?

malformed import path "dev.azure.com/abc/abc%20def/_git/repo-name" invalid character '%'

What could be done

Having % symbols can be quite ugly in an import in the first place. Perhaps an exception can be made for the %20 character and can be automatically aliased as a space character when using it in the code itself.

For instance if I have dev.azure.com/abc/abc%20def/_git/repo-name and I import it I could put:
import "dev.azure.com/abc/abc def/_git/repo-name"

Either way I think it's important for modules to support %20

[seankhliao]

Duplicate of #41540