Add utility functions for list results stream errors

Author: bbasata

list/list_resource.go

@@ -134,6 +134,25 @@ type ListResultsStream struct {
 // NoListResults is an iterator that pushes zero results.
 var NoListResults = func(func(ListResult) bool) {}
 
+// ListResultsStreamError returns a function that yields a single
+// [[ListResult]] with an error diagnostic
+func ListResultsStreamError(summary string, detail string) iter.Seq[ListResult] {
+	return func(push func(ListResult) bool) {
+		if !push(ListResultError(summary, detail)) {
+			return
+		}
+	}
+}
+
+// ListResultError constructs a [[ListResult]] with an error diagnostic
+func ListResultError(summary string, detail string) ListResult {
+	return ListResult{
+		Diagnostics: diag.Diagnostics{
+			diag.NewErrorDiagnostic(summary, detail),
+		},
+	}
+}
+
 // ListResult represents a listed managed resource instance.
 type ListResult struct {
 	// Identity is the identity of the managed resource instance.