Regression: Runtime.evaluate errors on polyfilled Promises

[brendankenny]

Getting Protocol error (Runtime.evaluate): Result of the evaluation is not a promise for all driver.evaluateAsync calls on test angular site like e.g. https://material2-app.firebaseapp.com/

#1037 handles this case (and we've tested it pretty thoroughly in the past), so need to investigate how this regressed.

[patrickhulce]

:(

[patrickhulce]

Found it. Looks like however Angular2 polyfills promise goes above and beyond what the smokehouse promise polyfill does and removing the new __nativePromise layer during feedback broke it for angular but not smokehouse. In a nutshell, there doesn't seem to be a way around explicitly constructing a new promise since returning a polyfilled Promise within a native Promise .then doesn't always work, just when you're testing ;)

[brendankenny]

looks like the problem was that zone.js not only overwrites the global Promise, it also overwrites Promise.prototype.then on the original global.

So even though we were using our window.__nativePromise, we were getting the overwritten window.__nativePromise.prototype.then, which returns a non-native promise :(

[brendankenny]

fixed in #1178

[paulirish]

some history from #11190 ...

Lighthouse backstory:
Zone aggressively polyfills promises including rewriting Promise.prototype.then which caused
problems for our evaluateAsync code where we rely on a Promise to work.
We serve this file in dbw_tester.html to make sure evaluateAsync, etc all works great
Serving this file via node_modules was a pain so we've replaced it with our own.
@see #1173
@see #1178
We were serving zone.js@0.7.3 from node_modules but that introduced complexity, so it was
vendored into a third_party folder.
@see #9672
Later we decided to stop using this fancy file altogether so we can just ignore drama from both
third_party placement and node_modules imports.
@see #11043
This promise polyfill isn't as aggressive as zone as it doesn't patch every interface
that returns a promise (https://github.com/angular/zone.js/blob/v0.7.3/dist/zone.js#L1589-L1611)
But we think that's ok.

but 11190 was a pain to land and the earlier annoyances calmed down.