Dots should be allowed in namespace for third-party module registry addresses

[aayushsrivastava]

Use Case

If I am using a third-party module registry, I should be allowed to use dots in the namespace. My organisation is not able to use registry as module source because we have a dot in our namespace. It is not easy to change the namespace.

For instance, I should be allowed to use example.com/my.namespace/name/targetsystem as a module source.

When I try to use the above as module source, I get the following error from Terraform CLI:
source address must have three more components after the hostname: the namespace, the name, and the target system

I checked the tests and found this assertion for the above error.

"missing part with explicit hostname": {
	input:   `foo.com/var/baz`,
	wantErr: `source address must have three more components after the hostname: the namespace, the name, and the target system`,
},

However, in the above usecase, all three components are provided after the hostname example.com.

Proposal

Based on the test suite, I believe this is a buggy implementation which is mistakenly stopping a use-case it didn't intend to. We should add a test case for example.com/my.namespace/name/targetsystem and change the implementation to make it green.

Contribution

I am open to contributing a solution if you need help. I haven't used Golang before so I will need some time to implement the solution though.