allow chunklist to handle unknowns

Chunklist should be able to return chunks containing unknown values.

lang/funcs/collection.go

@@ -379,7 +379,7 @@ var ChunklistFunc = function.New(&function.Spec{
 	},
 	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
 		listVal := args[0]
-		if !listVal.IsWhollyKnown() {
+		if !listVal.IsKnown() {
 			return cty.UnknownVal(retType), nil
 		}
 

lang/funcs/collection_test.go

@@ -993,13 +993,29 @@ func TestChunklist(t *testing.T) {
 				cty.UnknownVal(cty.String),
 			}),
 			cty.NumberIntVal(1),
+			cty.ListVal([]cty.Value{
+				cty.ListVal([]cty.Value{
+					cty.StringVal("a"),
+				}),
+				cty.ListVal([]cty.Value{
+					cty.StringVal("b"),
+				}),
+				cty.ListVal([]cty.Value{
+					cty.UnknownVal(cty.String),
+				}),
+			}),
+			false,
+		},
+		{
+			cty.UnknownVal(cty.List(cty.String)),
+			cty.NumberIntVal(1),
 			cty.UnknownVal(cty.List(cty.List(cty.String))),
 			false,
 		},
 	}
 
-	for _, test := range tests {
-		t.Run(fmt.Sprintf("chunklist(%#v, %#v)", test.List, test.Size), func(t *testing.T) {
+	for i, test := range tests {
+		t.Run(fmt.Sprintf("%d-chunklist(%#v, %#v)", i, test.List, test.Size), func(t *testing.T) {
 			got, err := Chunklist(test.List, test.Size)
 
 			if test.Err {