private static List<SearchChainInvocationSpec> extractSpecs(List<ResolveResult> results) {
        List<SearchChainInvocationSpec> errors = List.of();
        for (ResolveResult result : results) {
            if (result.invocationSpec() != null) {
                if (errors.isEmpty()) {
                    errors = List.of(result.invocationSpec());
                } else if (errors.size() == 1) {
                    errors = new ArrayList<>(errors);
                    errors.add(result.invocationSpec());
                } else {
                    errors.add(result.invocationSpec());
                }
            }
        }
        return errors;
    }
The name of the query property containing the source name added to the query to each source by this
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java