Support case-sensitive Go module names

[VJftw]

using strings.ToLower(mod) removes the ability to support case-sensitive Go modules names, for example github.com/antlr/antlr4/runtime/Go/antlr is currently being converted to github.com/antlr/antlr4/runtime/go/antlr which returns a 404 with the Go Proxy.

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I haven't tested this, but can't immediately see a reason for lowercasing the mod. Please share if so, and I'll try to find a better solution :)

[Tatskaari]

I think this makes sense, I'm just a little concerned that I added this for a reason... I will have to test this out in a few places before we land this.

[VJftw]

👍 - it does feel like it was done purposefully! Please test away, let me know if I can help

[peterebden]

I recall some nonsense with Sirupsen/logrus and sirupsen/logrus where various things seemed to be inconsistent about it.

I agree that we probably shouldn't be doing this though.

[VJftw]

Ah I see (sirupsen/logrus#543). I think I could probably update this PR to allow end-users to override a module name, e.g. end-users add GoModuleRename=github.com/Sirupsen/logrus=github.com/sirupsen/logrus in .plzconfig.

[peterebden]

I think hopefully we don't need that in the config; i think you could achieve the same with a go_mod_download to instruct it more directly where to get the source from

[Tatskaari]

Maybe we can just try and resolve both? Go already tries a bunch of arbitrary module names to figure out what the module path is so I don't think that's as ugly as it first sounds.

[VJftw]

Maybe we can just try and resolve both? Go already tries a bunch of arbitrary module names to figure out what the module path is so I don't think that's as ugly as it first sounds.

Just updated the PR to do this instead, so it shouldn't break any existing functionality 👍. Let me know what y'all think :)

[Tatskaari]

Thanks for this! This makes a lot of sense.

[VJftw]

you'll need to merge it as I don't have write access 😄

[Tatskaari]

you'll need to merge it as I don't have write access smile

Sorry! I was waiting for the build but got distracted. :)