check for typed nulls in flatten func

zclconf · Aug 8, 2022 · ee48093 · ee48093
1 parent 834994b
commit ee48093
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diff --git a/cty/function/stdlib/collection.go b/cty/function/stdlib/collection.go
@@ -525,6 +525,11 @@ func flattener(flattenList cty.Value) ([]cty.Value, []cty.ValueMarks, bool) {
 	if len(flattenListMarks) > 0 {
 		markses = append(markses, flattenListMarks)
 	}
+
+	if flattenList.IsNull() {
+		return nil, markses, true
+	}
+
 	if !flattenList.Length().IsKnown() {
 		// If we don't know the length of what we're flattening then we can't
 		// predict the length of our result yet either.

diff --git a/cty/function/stdlib/collection_test.go b/cty/function/stdlib/collection_test.go
@@ -1825,6 +1825,17 @@ func TestFlatten(t *testing.T) {
 		Want cty.Value
 		Err  string
 	}{
+		{
+			// typed and untyped null args
+			cty.TupleVal([]cty.Value{
+				cty.NullVal(cty.DynamicPseudoType),
+				cty.NullVal(cty.List(cty.DynamicPseudoType)),
+				cty.NullVal(cty.List(cty.String)),
+			}),
+			cty.TupleVal([]cty.Value{cty.NullVal(cty.DynamicPseudoType)}),
+			"",
+		},
+
 		{ // Empty case is easy
 			cty.ListValEmpty(cty.String),
 			cty.EmptyTupleVal,