This is a long-time-lasted feature for the ExpressionLanguage component. I've been waiting for the support of Nullsafe operator in expressions dealing with mutable objects, until I finally decided to work on it once for all 👍

The lack of nullsafety feature has been repeatedly reported as a BUG several time (e.g #45411 & #21691) when it is actually a missing feature.

Currently, expressions like foo.bar assumes that the property bar "always" exists on the object foo and if doesn't the parser throws a RuntimeException. Although, sometimes, that's exactly the behavior we need, some other times we may work with mutable objects with uncontrolled structure, thus, such assumption is error-prone and will force adding extra checks making the expression uglier and less readable.

The proposed work, introduces the support for the ?. syntax alongside with the usual . syntax to help working with objects with dynamic structure. The two notations works identically in all normal cases. The difference occurs when trying to access non-existant properties and/or methods where the . notation will throw a RuntimeException as usual and the ?. notation will return null instead and no errors nor exceptions will be thrown. Hence the name "Null-Safe".

PS: This work account ONLY for accessing object's properties and methods. It does not account for non-existant array items which is a seperate problem that can be addressed by introducing the null coalescing operator. Another feature that I'm currently working on as well 💯