CachingAssetBundle._fetchString gives poor error message #7715
Description
Ian asked me to report this bug. Loading the asset from the .flx file appears to be failing. It would be good if we were given the asset string whose load failed.
Logs
[00206.770] 09972.10019> [ERROR:dart_error.cc(16)] Unhandled exception:
[00206.770] 09972.10019> NoSuchMethodError: The getter 'buffer' was called on null.
[00206.770] 09972.10019> Receiver: null
[00206.770] 09972.10019> Tried calling: buffer
[00206.770] 09972.10019> #0 Object._noSuchMethod (dart:core-patch/object_patch.dart:44)
[00206.770] 09972.10019> #1 Object.noSuchMethod (dart:core-patch/object_patch.dart:47)
[00206.770] 09972.10019> #2 CachingAssetBundle._fetchString.<_fetchString_async_body> (package:flutter/src/services/asset_bundle.dart:148)
[00206.770] 09972.10019> #3 _RootZone.runUnary (dart:async/zone.dart:1404)
[00206.770] 09972.10019> #4 _FutureListener.handleValue (dart:async/future_impl.dart:131)
[00206.770] 09972.10019> #5 _Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:637)
[00206.770] 09972.10019> #6 _Future._propagateToListeners (dart:async/future_impl.dart:667)
[00206.770] 09972.10019> #7 _Future._completeWithValue (dart:async/future_impl.dart:477)
[00206.770] 09972.10019> #8 _Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:528)
[00206.770] 09972.10019> #9 _microtaskLoop (dart:async/schedule_microtask.dart:41)
[00206.770] 09972.10019> #10 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50)
[00206.835] 09972.10019> EXCEPTION CAUGHT BY SERVICES
[00206.839] 09972.10019> The following message was thrown resolving a single-frame image stream:
[00206.839] 09972.10019> Unable to read data
[00206.840] 09972.10019>
[00206.840] 09972.10019> When the exception was thrown, this was the stack:
[00206.853] 09972.10019> #0 AssetBundleImageProvider.loadAsync.<loadAsync_async_body> (package:flutter/src/services/image_provider.dart:284)
[00206.853] 09972.10019> (elided 8 frames from package dart:async)
[00206.860] 09972.10019>
[00206.860] 09972.10019> Image provider: AssetImage(bundle: null, name: "packages/armadillo/res/Background.jpg")
[00206.860] 09972.10019> Image key: AssetBundleImageKey(bundle: PlatformAssetBundle@686690892(), name:
[00206.860] 09972.10019> "packages/armadillo/res/Background.jpg", scale: 1.0)
[00206.860] 09972.10019>
[00206.860] 09972.10019> Another exception was thrown: Unable to read data
[00206.860] 09972.10019> Another exception was thrown: Unable to read data