Fix go_option that contains both path and pkg

[marwan-at-work]

This PR adds a new check to the go_option parser to see if it includes a semi-colon. If it does, that means the user has already provided both the import path as well as the package name and that Twirp shouldn't try to deduce either of them.

In protobuf-go's v2, this is going to be the new default. See the referenced issue for more details.

Fixes #280

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[chetanvalagit]

@marwan-at-work can you please add some detail description as part of PR?

Reference Example: #277

[marwan-at-work]

@chetanvalagit done :)

[chetanvalagit]

@marwan-at-work thank you very much. I am really sorry for the one more quick request: Can you please add last line too as shown in Reference Example: #277 if you are fine with that.

[chetanvalagit]

@marwan-at-work thank you very much. I am really sorry for the one more quick request: Can you please add last line too as shown in Reference Example: #277 if you are fine with that

[marwan-at-work]

@chetanvalagit done ✌️

[amcohen-twitch]

Upon review, we're generally on board with this implementation. Could you please add a test to the existing tests for this function? https://github.com/twitchtv/twirp/blob/424ec823543050237314da4efe3ac642abb618f6/protoc-gen-twirp/go_naming_test.go

[marwan-at-work]

@amcohen-twitch I don't think the link you sent me actually points to the function I modified. The link you sent is testing the parseGoPackageOption function which actually seems to be doing the correct logic. While, my function was missing the same logic.

Furthermore, that test function seems to be completely wrong, because it's shadowing all the test cases with empty strings.

Would you like me to create a new test for my own change, and also fix the tests you pointed out above?

[marwan-at-work]

@amcohen-twitch I fixed the linked test cases and added new ones for my particular fix. Happy to change things up if I missed something here.

[advdv]

Just wanted to say that i'm looking forward to this change. Hopefully it can be merged soon! Thank you

[marwan-at-work]

@amcohen-twitch any luck on the above? Thanks!

[amcohen-twitch]

@marwan-at-work Apologies for the delay in followup, we were out of office due to the holidays. Upon subsequent review, we're good with merging this.