Don't print UnexpectedStateError.LastError when it's nil

[kayrus]

SDK version

...
github.com/hashicorp/terraform-plugin-sdk/v2 v2.34.0

Use-cases

In case when the retry func faces an unexpected resource status it returns unexpected state 'ACTIVE', wanted target 'DELETED'. last error: %!s(<nil>).

Attempted Solutions

Proposal

There should be more cleaner error report, when LastError is nil: unexpected state 'ACTIVE', wanted target 'DELETED', e.g.

func (e *UnexpectedStateError) Error() string {
        if e.LastError == nil {
                return fmt.Sprintf( 
                        "unexpected state '%s', wanted target '%s'.",
                        e.State,
                        strings.Join(e.ExpectedState, ", "),
                )
        }
        return fmt.Sprintf(
                "unexpected state '%s', wanted target '%s'. last error: %s",
                e.State,
                strings.Join(e.ExpectedState, ", "),
                e.LastError,
        )
}

References

terraform-plugin-sdk/helper/retry/error.go

Line 45 in 4c604df

"unexpected state '%s', wanted target '%s'. last error: %s",

https://github.com/search?q=%22last+error%3A+%25%21s%28%3Cnil%3E%29%22&type=issues