DynamoDBAttributeValue.String() accessor method inconsistent with documented behavior

[TylerHendrickson]

Problem

The documented behavior for the DynamoDBAttributeValue.String() method, similar to the other accessor methods, states:

Method panics if the attribute is not of type String.

However, this does not appear to be the case.

Example

Using this code:

func IncorrectBehaviorExample() {
	input := []byte(`{"MyField": {"BOOL": true}}`)
	var item map[string]events.DynamoDBAttributeValue
	if err := json.Unmarshal(input, &item); err != nil {
		panic(err)
	}
	fmt.Println("Result:", item["MyField"].String())
}

does not panic, but outputs Result: {true 1}.

This is unlike the other accessor methods, such as .Number(), e.g.:

func CorrectBehaviorExample() {
	input := []byte(`{"MyField": {"BOOL": true}}`)
	var item map[string]events.DynamoDBAttributeValue
	if err := json.Unmarshal(input, &item); err != nil {
		panic(err)
	}
	fmt.Println("Result:", item["MyField"].Number())
}

which panics with panic: accessor called for incompatible type, requested type 5 but actual type was 1.

Suggestions

Either of:

• Preferred: The method should panic if the attribute is not of type String, which is consistent with the documented behavior as well as the behavior of the other accessor methods.
• Update the documentation so that it correctly reflects the behavior of the method.

Additional information

• Observed when using github.com/aws/aws-lambda-go v1.41.0
• Go 1.20