Arvados

Maybe related to this: go-staticcheck (via vscode) is showing me a warning that says:

unreachable case clause: git.arvados.org/arvados.git/sdk/go/keepclient.OversizeBlockError will always match before git.arvados.org/arvados.git/sdk/go/keepclient.InsufficientReplicasError (SA4020)

...for the case keepclient.InsufficientReplicasError: in keepproxy.go's Put() function. Both types are aliases of error so it seems the compiler won't take them as different.

type InsufficientReplicasError error

type OversizeBlockError error

    switch err.(type) {
    case nil:
        status = http.StatusOK
        _, err = io.WriteString(resp, locatorOut)

    case keepclient.OversizeBlockError:
        // Too much data
        status = http.StatusRequestEntityTooLarge

    case keepclient.InsufficientReplicasError:
}

I think this is an inconsistency in Go. If you declare a type that is the same as another type, at compile time they will act like different types, but at runtime they will be the same type.

Does this work?

type InsufficientReplicasError struct { error }

Updates at e10c23d41 - branch 16665-keepproxy-spurious-413-status
Test run: developer-run-tests: #2606

• Following Peter's suggestion, updates InsufficientReplicasError & OversizeBlockError error types by wrapping error in a struct, so that the former isn't shadowed by the latter.
• Updates tests.

LGTM, thanks.

BTW, about the language issue: error is an interface type, therefore type FooError error defines an interface type, therefore anything that implements the error interface { Error() string } has to match FooError in a type switch. After this fix, type FooError struct { error } is a concrete type, so FooError in a type switch is unambiguous. I think it would have been more normal to use var ErrFoo = errors.New(...) and if err == ErrFoo { ... } for these... oh well.