Occasional incorrect bubble sizes - must implement hash?

[walsh2000]

@jessesquires

Occasionally I see heights of chat bubbles clearly wrong.
-- Typically the bubble for a single line of text is as tall as a bubble for an image, or an image is squished down to the height of a single line of text.

I suspected the CGSize cache (_messageBubbleCache) &/or cell reuse, because the incorrect size was typically when a larger bubble went offscreen because of an incoming chat message. So I investigated that angle. _messageBubbleCache uses messageItem.hash for the cache key. The demo application provides a custom implementation for -[hash], but my application uses custom classes for JSQMessageData.

I believe the problem is that my JSQMessageData does not implement hash, and therefore uses the NSObject implementation. It appears that the NSObject implementation is to return the object's pointer as the hash value. So, if one of my JSQMessageData objects representing a picture is deallocated and a single-line text is allocated at the same address, the cache will produce a false-positive hit.

This is clearly my problem with an obvious solution, but I was thinking that the JSQMessageViewController library could have helped me avoid this by making -[hash] a required method on the JSQMessageData protocol. (or define its own selector for the cache key)

What do you think about that as an enhancement request?

[jessesquires]

Good catch @walsh2000 !

I think making hash required is the best solution.

[gblazex]

+1 it also happens if you are using asynchronous loading of images (in which case simply self.image.hash is not going to cut it).