x/pkgsite: support versions tab for directory view

[julieqiu]

The URL https://pkg.go.dev/golang.org/x/mod?tab=subdirectories currently shows information for v0.1.0 of that module.

It would be useful to be able to click on the Versions tab to see what other versions are known. At the moment, that tab is greyed out.

[nickel8448]

Hey @julieqiu mod is a directory that has packages and commands. In this directory, some of the packages like lazyregexp have two versions available v0.2.0 and v0.3.0 and other packages like gosumcheck have three different versions. In this case, if we decide to make the tab Versions clickable what information should be visible on that tab?

Please let me know what your thoughts are about this. Thanks!

[julieqiu]

It should return the package available in the module version corresponding to that path. So for https://pkg.go.dev/golang.org/x/mod@v0.3.0, only show packages in v0.3.0 of golang.org/x/mod.

You should be able to just add a tabVersions case to fetchDetailsForDirectory, and use the existing fetchVersionDetails.

Note that this will only work with the new data model, so you will need to add the experiments use-path-info and use-directories locally. You can do that by running:

go run devtools/cmd/experiment/experiment.go create use-path-info
go run devtools/cmd/experiment/experiment.go create use-directories

[nickel8448]

Thanks for the explanation. I will give this try and send a change list by Friday EOD.

Thanks,

[nickel8448]

Apologies for the delay. Starting work on this now.