add getPromise call to access removed then method of Deferred

[noahlemen]

The then method of Deferred was removed (see D9308668 internally) -- the RelayMutationRequest (extending Deferred) request now must call getPromise() to access the underlying Promise methods

note that this change to fbjs/Deferred has not yet been synced to Github, so this only occurs internally -- error was reported in T33316897

[bvaughn]

note that this change to fbjs/Deferred has not yet been synced to Github

I think you're saying that removing .then() hasn't yet been synced, but the getPromise() API has already been release (and so is safe to switch to)?

[noahlemen]

yup! the getPromise method was not added, it is already in the class. just that then has not yet been removed.

https://github.com/facebook/fbjs/blob/cfd39964ba4b9ce351c314ed512e654ffa9cad26/packages/fbjs/src/core/Deferred.js#L35-L37

[bvaughn]

Cool. Just checked and it looks like you're right that the earliest version of fbjs we've pinned to does include getPromise() so... 👍

[bvaughn]

This looks like a safe change to me 👍

[noahlemen]

thanks @bvaughn!