running `coverage check --public-only` reports 0 typables in a dir without config

[jorenham]

I'm guessing this is because the path -> module name derivation gives __unknown__ when there's only the fallback search path, so nothing matches the public FQNs.

Verified against main.

This is a different issue than (and has a different cause as) #4034

[jorenham]

#claim

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[kinto0]

I think it was originally intentional that we had this behavior. @connernilsen would know more

• upwards search is nondeterministic on different machines (depending on where the project is) so different projects will have different CLI checks
• perf? (probably not an issue)

what is the use case of a coverage check without a config? could we instead issue a stronger warning to add a config?

[jorenham]

I think it was originally intentional that we had this behavior

Ah, that kinda explains the net-negative diff of #4136

what is the use case of a coverage check without a config?

Now, running pyrefly coverage check --public-only will report 0 typables if there's no config. #4136 changes this so that it will instead report the same number of typables as when run without --public-only. I guess that's still a bit confusing in its own way, but at the very least the result is more useful less useless.

could we instead issue a stronger warning to add a config?

I like that!
I slightly prefer doing that as well though, i.e. showing both a warning and reporting all typables (instead of 0 typables).