Merge pull request #143 from hashicorp/b-invalid-object-value

Fix panic when decoding invalid value structure into struct

decoder.go

@@ -489,7 +489,7 @@ func (d *decoder) decodeStruct(name string, node ast.Node, result reflect.Value)
 	// the yacc parser would always ensure top-level elements were arrays. The new
 	// parser does not make the same guarantees, thus we need to convert any
 	// top-level literal elements into a list.
-	if _, ok := node.(*ast.LiteralType); ok {
+	if _, ok := node.(*ast.LiteralType); ok && item != nil {
 		node = &ast.ObjectList{Items: []*ast.ObjectItem{item}}
 	}
 

decoder_test.go

@@ -328,6 +328,20 @@ func TestDecode_interface(t *testing.T) {
 				},
 			},
 		},
+
+		// Terraform GH-8295 sanity test that basic decoding into
+		// interface{} works.
+		{
+			"terraform_variable_invalid.json",
+			false,
+			map[string]interface{}{
+				"variable": []map[string]interface{}{
+					map[string]interface{}{
+						"whatever": "abc123",
+					},
+				},
+			},
+		},
 	}
 
 	for _, tc := range cases {
@@ -676,6 +690,26 @@ func TestDecode_structureMap(t *testing.T) {
 	}
 }
 
+func TestDecode_structureMapInvalid(t *testing.T) {
+	// Terraform GH-8295
+
+	type hclVariable struct {
+		Default     interface{}
+		Description string
+		Fields      []string `hcl:",decodedFields"`
+	}
+
+	type rawConfig struct {
+		Variable map[string]*hclVariable
+	}
+
+	var actual rawConfig
+	err := Decode(&actual, testReadFile(t, "terraform_variable_invalid.json"))
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
 func TestDecode_interfaceNonPointer(t *testing.T) {
 	var value interface{}
 	err := Decode(value, testReadFile(t, "basic_int_string.hcl"))

test-fixtures/terraform_variable_invalid.json

@@ -0,0 +1,5 @@
+{
+  "variable": {
+    "whatever": "abc123"
+  }
+}