refactor(di): subclasses of BaseException should be immutable

[jeffbcross]

(Related to #2580 and #2570)

The AbstractBindingError class in di/exceptions extends BaseException from facade/lang, and provides an addKey method to append the error's message with more information. @yjbanov suggests (and I agree) that it would be better to implement the addKey method to return a new AbstractBindingError, merging the input with the existing instance's message, to encourage/enforce immutability.

(There may be other subclasses that need to change as well; I just wanted to get this issue open before I left the office).

@vsavkin, I'm happy to make this change if you're not opposed to this (since you're the one who's done the most work on di).

[jeffbcross]

(I spoke with @vsavkin in person and he affirmed this approach)

[mhevery]

I have tried to merge #2923 in. I have rebased on master, but realized that current implementation has an issue because it turns concrete exception (ie InstantiationError) into a (AbstractBaseError). To fix this every subclass of AbstractBindingError has to implement its own addKey method. The issue is that the concrete constructors take Key rather then List<Key>, so they have to have their signatures changed.

I have decided to abandon this since added code payload and constructor signature complexity does not justify the benefit of the immutability. Given that the exception are only mutated in DI, I see very little value in turning it into immutable code.

Closing.

[mhevery]

WONT_FIX

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}