Replace unpack's replace semantics with append

Blueprint was using "replace" semantics when unpacking properties
into property structs, meaning if a module factory pre-set property
values they would be overwritten by whatever was in the Blueprint
file.  This is different than what would happen if the same property
was updated using the Append*Properties functions in proptools, which
would use "append" semantics, which append strings and lists,
logically ORs booleans and replaces pointers to strings and booleans.
Replace unpack's semantics with append semantics for consistency.
Any previous users of pre-set properties can move to using a pointer
to a string or boolean if they want the old behavior.

Test: unpack_test.go
Test: extend_test.go
Change-Id: I02eebe80916e578938142f8e76889bd985223afc

proptools/extend.go

@@ -238,7 +238,7 @@ func extendMatchingProperties(dst []interface{}, src interface{}, filter ExtendP
 
 func extendPropertiesRecursive(dstValues []reflect.Value, srcValue reflect.Value,
 	prefix string, filter ExtendPropertyFilterFunc, sameTypes bool,
-	order ExtendPropertyOrderFunc) error {
+	orderFunc ExtendPropertyOrderFunc) error {
 
 	srcType := srcValue.Type()
 	for i, srcField := range typeFields(srcType) {
@@ -373,9 +373,10 @@ func extendPropertiesRecursive(dstValues []reflect.Value, srcValue reflect.Value
 				}
 			}
 
-			prepend := false
+			order := Append
-			if order != nil {
+			if orderFunc != nil {
-				b, err := order(propertyName, dstField, srcField,
+				var err error
+				order, err = orderFunc(propertyName, dstField, srcField,
 					dstFieldInterface, srcFieldInterface)
 				if err != nil {
 					return &ExtendPropertyError{
@@ -383,15 +384,33 @@ func extendPropertiesRecursive(dstValues []reflect.Value, srcValue reflect.Value
 						Err:      err,
 					}
 				}
-				prepend = b == Prepend
 			}
 
+			ExtendBasicType(dstFieldValue, srcFieldValue, order)
+		}
+
+		if len(recurse) > 0 {
+			err := extendPropertiesRecursive(recurse, srcFieldValue,
+				propertyName+".", filter, sameTypes, orderFunc)
+			if err != nil {
+				return err
+			}
+		} else if !found {
+			return extendPropertyErrorf(propertyName, "failed to find property to extend")
+		}
+	}
+
+	return nil
+}
+
+func ExtendBasicType(dstFieldValue, srcFieldValue reflect.Value, order Order) {
+	prepend := order == Prepend
+
 	switch srcFieldValue.Kind() {
 	case reflect.Bool:
 		// Boolean OR
 		dstFieldValue.Set(reflect.ValueOf(srcFieldValue.Bool() || dstFieldValue.Bool()))
 	case reflect.String:
-				// Append the extension string.
 		if prepend {
 			dstFieldValue.SetString(srcFieldValue.String() +
 				dstFieldValue.String())
@@ -442,19 +461,6 @@ func extendPropertiesRecursive(dstValues []reflect.Value, srcValue reflect.Value
 			panic(fmt.Errorf("unexpected pointer kind %s", ptrKind))
 		}
 	}
-		}
-		if len(recurse) > 0 {
-			err := extendPropertiesRecursive(recurse, srcFieldValue,
-				propertyName+".", filter, sameTypes, order)
-			if err != nil {
-				return err
-			}
-		} else if !found {
-			return extendPropertyErrorf(propertyName, "failed to find property to extend")
-		}
-	}
-
-	return nil
 }
 
 type getStructEmptyError struct{}

unpack.go

@@ -240,27 +240,7 @@ func unpackStructValue(namePrefix string, structValue reflect.Value,
 
 		var newErrs []error
 
-		switch kind := fieldValue.Kind(); kind {
+		if fieldValue.Kind() == reflect.Struct {
-		case reflect.Bool:
-			newErrs = unpackBool(fieldValue, packedProperty.property)
-		case reflect.String:
-			newErrs = unpackString(fieldValue, packedProperty.property)
-		case reflect.Slice:
-			newErrs = unpackSlice(fieldValue, packedProperty.property)
-		case reflect.Ptr:
-			switch ptrKind := fieldValue.Type().Elem().Kind(); ptrKind {
-			case reflect.Bool:
-				newValue := reflect.New(fieldValue.Type().Elem())
-				newErrs = unpackBool(newValue.Elem(), packedProperty.property)
-				fieldValue.Set(newValue)
-			case reflect.String:
-				newValue := reflect.New(fieldValue.Type().Elem())
-				newErrs = unpackString(newValue.Elem(), packedProperty.property)
-				fieldValue.Set(newValue)
-			default:
-				panic(fmt.Errorf("unexpected pointer kind %s", ptrKind))
-			}
-		case reflect.Struct:
 			localFilterKey, localFilterValue := filterKey, filterValue
 			if k, v, err := HasFilter(field.Tag); err != nil {
 				errs = append(errs, err)
@@ -280,52 +260,62 @@ func unpackStructValue(namePrefix string, structValue reflect.Value,
 			}
 			newErrs = unpackStruct(propertyName+".", fieldValue,
 				packedProperty.property, propertyMap, localFilterKey, localFilterValue)
-		default:
+
-			panic(fmt.Errorf("unexpected kind %s", kind))
-		}
 			errs = append(errs, newErrs...)
 			if len(errs) >= maxErrors {
 				return errs
 			}
+
+			continue
+		}
+
+		// Handle basic types and pointers to basic types
+
+		propertyValue, err := propertyToValue(fieldValue.Type(), packedProperty.property)
+		if err != nil {
+			errs = append(errs, err)
+			if len(errs) >= maxErrors {
+				return errs
+			}
+		}
+
+		proptools.ExtendBasicType(fieldValue, propertyValue, proptools.Append)
 	}
 
 	return errs
 }
 
-func unpackBool(boolValue reflect.Value, property *parser.Property) []error {
+func propertyToValue(typ reflect.Type, property *parser.Property) (reflect.Value, error) {
+	var value reflect.Value
+
+	var ptr bool
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+		ptr = true
+	}
+
+	switch kind := typ.Kind(); kind {
+	case reflect.Bool:
 		b, ok := property.Value.Eval().(*parser.Bool)
 		if !ok {
-		return []error{
+			return value, fmt.Errorf("%s: can't assign %s value to bool property %q",
-			fmt.Errorf("%s: can't assign %s value to bool property %q",
+				property.Value.Pos(), property.Value.Type(), property.Name)
-				property.Value.Pos(), property.Value.Type(), property.Name),
 		}
-	}
+		value = reflect.ValueOf(b.Value)
-	boolValue.SetBool(b.Value)
-	return nil
-}
-
-func unpackString(stringValue reflect.Value,
-	property *parser.Property) []error {
 
+	case reflect.String:
 		s, ok := property.Value.Eval().(*parser.String)
 		if !ok {
-		return []error{
+			return value, fmt.Errorf("%s: can't assign %s value to string property %q",
-			fmt.Errorf("%s: can't assign %s value to string property %q",
+				property.Value.Pos(), property.Value.Type(), property.Name)
-				property.Value.Pos(), property.Value.Type(), property.Name),
 		}
-	}
+		value = reflect.ValueOf(s.Value)
-	stringValue.SetString(s.Value)
-	return nil
-}
-
-func unpackSlice(sliceValue reflect.Value, property *parser.Property) []error {
 
+	case reflect.Slice:
 		l, ok := property.Value.Eval().(*parser.List)
 		if !ok {
-		return []error{
+			return value, fmt.Errorf("%s: can't assign %s value to list property %q",
-			fmt.Errorf("%s: can't assign %s value to list property %q",
+				property.Value.Pos(), property.Value.Type(), property.Name)
-				property.Value.Pos(), property.Value.Type(), property.Name),
-		}
 		}
 
 		list := make([]string, len(l.Values))
@@ -338,8 +328,19 @@ func unpackSlice(sliceValue reflect.Value, property *parser.Property) []error {
 			list[i] = s.Value
 		}
 
-	sliceValue.Set(reflect.ValueOf(list))
+		value = reflect.ValueOf(list)
-	return nil
+
+	default:
+		panic(fmt.Errorf("unexpected kind %s", kind))
+	}
+
+	if ptr {
+		ptrValue := reflect.New(value.Type())
+		ptrValue.Elem().Set(value)
+		value = ptrValue
+	}
+
+	return value, nil
 }
 
 func unpackStruct(namePrefix string, structValue reflect.Value,

unpack_test.go

@@ -498,6 +498,49 @@ var validUnpackTestCases = []struct {
 			},
 		},
 	},
+
+	// Factory set properties
+	{
+		input: `
+			m {
+				string: "abc",
+				string_ptr: "abc",
+				bool: false,
+				bool_ptr: false,
+				list: ["a", "b", "c"],
+			}
+		`,
+		output: []interface{}{
+			struct {
+				String     string
+				String_ptr *string
+				Bool       bool
+				Bool_ptr   *bool
+				List       []string
+			}{
+				String:     "012abc",
+				String_ptr: proptools.StringPtr("abc"),
+				Bool:       true,
+				Bool_ptr:   proptools.BoolPtr(false),
+				List:       []string{"0", "1", "2", "a", "b", "c"},
+			},
+		},
+		empty: []interface{}{
+			&struct {
+				String     string
+				String_ptr *string
+				Bool       bool
+				Bool_ptr   *bool
+				List       []string
+			}{
+				String:     "012",
+				String_ptr: proptools.StringPtr("012"),
+				Bool:       true,
+				Bool_ptr:   proptools.BoolPtr(true),
+				List:       []string{"0", "1", "2"},
+			},
+		},
+	},
 }
 
 type EmbeddedStruct struct{ Name string }