Feedback Thread: DIP 1042--ProtoObject--Community Review Round 1

[RazvanN]

On Monday, 10 January 2022 at 14:32:54 UTC, Elronnd wrote:

> This is fine; hashing was not an advertised part of their API, 
> and no one was using it anyway.  No one's code broke as a 
> result of this.  I would nominally feel very comfortable making 
> such a change and would not consider it a compatibility break.  
> _Except_ that, when a user tries to combine libraries X and Y, 
> their code will break.
>

Are you referring to the case where a method from library Y 
returns
an instance of something that inherits ProtoObject (but not 
Object)
and then when the instance is passed to some_function in library 
X,
some_function might make assumptions that are false about the 
instance
(for example, assumes that the instance has a toHash)? Indeed, 
this is
a bit nasty, but what could be done to ease the transition: 
library Y owner
can put some deprecated toHash function in his classes that 
inherit
ProtoObject. Even better, we will provide some utilities [1] that 
make it
trivial to implement the methods that Object provides. 
Eventually, Object
should be deprecated and that will make everyone upgrade their 
code to
ProtoObject.


[1] https://github.com/dlang/phobos/pull/7049