add gh config clear-cache command

[ffalor]

Fixes #7242

It assumes cachedir is at $TMPDIR/gh-cli-cache. I wasn't sure how we could get the CacheDir value configured for go-gh.

[samcoe]

@ffalor Thanks for getting started on this work. Rather than hardcoding the cache directory I would rather see us add a CacheDir function to the config package in go-gh. Would you feel up to adding that and then utilizing that in this PR?

[ffalor]

I agree, I'm on vacation this week. If it can wait that long, I'd be happy to add it once I get back.

[ffalor]

@samcoe do you mind giving some more guidance on this? I looked into go-gh. It looks like the cachedir is set in the api package in go-gh is this something that would be stored in the config or retrievable from config? I'm still familiarizing myself with how both cli and go-gh works. Sorry if this is extremely obvious.

[samcoe]

@ffalor Yeah of course, no problem.

So my proposal is that we create a new PR in the go-gh repo that modifies this line of code to be opts.CacheDir = config.CacheDir() and then we add a CacheDir() function to the config package. Something like:

func CacheDir() string {
    return filepath.Join(os.TempDir(), "gh-cli-cache")
}

Once that PR is merged in the go-gh repo I can make a new release of go-gh. We can then update the version of go-gh in use in gh to the new version and utilize the new config.CacheDir() function instead of hardcoding filepath.Join(os.TempDir(), "gh-cli-cache").

Does that help clarify my previous comment? Let me know if anything is unclear.

[ffalor]

Thank you, that part made sense to me, but is there a scenario where we care about the CacheDir being overridden (line 70)? In that scenario the clear-cache command would be clearing the cache of the default. This would require the CLI to override the cachedir when creating the client which seems unlikely, but I didn't want to open that possibility up without asking.

Of course - I could be thinking about this wrong or overthinking this.

[samcoe]

@ffalor I don't think we care about the scenario where the CacheDir is overridden. gh does not overwrite the CacheDir and this new command is only supposed to clear the cache that gh uses. If an extension author using go-gh decides to override the CacheDir than we should leave it to them to provide the ability to clear their extension's cache.

[samcoe]

@ffalor I created a new release of go-gh with the CacheDir changes in it. This should be unblocked now 👍

[ffalor]

Sorry for the delay!

[samcoe]

@ffalor Thanks for finishing this off! Looks good to me. I pushed a small commit adding a bit of 💅

[andyfeller]

✨ @ffalor @samcoe : thank you both for implementing and reviewing this improvement! ❤️