Handle exceptions thrown in done handles attached to ProjectManager.getAllFiles

[iwehrman]

ProjectManager.getAllFiles currently returns a new promise to each caller, but if one of the callers attaches a done handler to its promise that throws an exception then no further done handlers attached to later promises returned from getAllFiles are executed. This is because jQuery promises are dumb.

Addresses #6401.

CC @redmunds

[jasonsanjose]

Reviewing

[jasonsanjose]

You say in the description we currently return a new promise. I think you mean that your PR adds this new behavior right? It looks like the old code would return the same promise for every call.

[jasonsanjose]

Maybe I'm reading this in the wrong context...but doesn't this try/catch handle exceptions from done handlers?

[iwehrman]

This doesn't doesn't directly catch exceptions thrown from the done handlers. But it's possible for an exception handler to throw while flies up through the resolve call, which breaks that deferred. If we let it go at this point it would also break _allFilesPromise, which is what we really care about protecting, since that is what's shared.

[jasonsanjose]

@iwehrman review complete

[redmunds]

What is _allFilesPromise? This is the only reference to it I can find.

[iwehrman]

Typo fixed.

[redmunds]

I verified that this fixes the issue.

[iwehrman]

@jasonsanjose We do currently return a new promise. That's what the return _getAllFiles().then() call does. jQuery then constructs and returns a new promise instead of just adding another handler like done. But what's CRAZY is that if the new promise created by then has a bad done handler that throws an exception, it screws up the parent promise and all subsequent promises created by then.

[iwehrman]

Ready for re-review.

[jasonsanjose]

Reviewing again. Looks like the travis error is due to github's services being down. I'll manually run the PR process locally.

[jasonsanjose]

Ah thanks @iwehrman. I see now what you mean about the p3 state being messed up. Merging.