Handle flutter build errors when http imports are used #27103
Description
While they are supported in the standalone Dart VM, http/https URI schemes in import directives are unsupported in Flutter. When detected, we should emit a clear, actionable error message.
Repro instructions
flutter create example
cd example
Edit lib/main.dart to add an http/https import, such as:
import 'http://raw.githubusercontent.com/dart-lang/coverage/master/test/test_files/test_app_isolate.dart';
Run the app on an iOS/Android simulator/emulator:
flutter run -d iPhone
Behaviour
Expected behaviour: warning that HTTP/HTTPS imports are unsupported.
Actual behaviour:
% flutter run -d iPh
Oops; flutter has exited unexpectedly.
Sending crash report to Google.
Crash report sent (report ID: 6c9495d6fdcce621)
Crash report written to /Users/cbracken/src/deleteme/flutter_01.log;
please let us know at https://github.com/flutter/flutter/issues.
The result of flutter build ios is slightly better, though the error message is still somewhat misleading in that case:
lib/main.dart:2:8: Error: Error when reading 'http://raw.githubusercontent.com/dart-lang/coverage/master/test/test_files/test_app_isolate.dart': StandardFileSystem only supports
file:* and data:* URIs
import 'http://raw.githubusercontent.com/dart-lang/coverage/master/test/test_files/test_app_isolate.dart';
^
Exception
UnsupportedError: Unsupported operation: Cannot extract a file path from a https URI
#0 _SimpleUri.toFilePath (dart:core/uri.dart:4587:7)
#1 DartDependencySetBuilder.build (package:flutter_tools/src/dart/dependencies.dart:91:58)
#2 HotRunner._refreshDartDependencies (package:flutter_tools/src/run_hot.dart:128:69)
<asynchronous suspension>
#3 HotRunner.run (package:flutter_tools/src/run_hot.dart:287:16)
<asynchronous suspension>
#4 RunCommand.runCommand (package:flutter_tools/src/commands/run.dart:392:37)
<asynchronous suspension>
#5 FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:551:18)
#6 _asyncThenWrapperHelper.<anonymous closure> (dart:async/runtime/libasync_patch.dart:77:64)
#7 _rootRunUnary (dart:async/zone.dart:1132:38)
#8 _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#9 _FutureListener.handleValue (dart:async/future_impl.dart:126:18)
#10 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:639:45)
#11 Future._propagateToListeners (dart:async/future_impl.dart:668:32)
#12 Future._complete (dart:async/future_impl.dart:473:7)
#13 _SyncCompleter.complete (dart:async/future_impl.dart:51:12)
#14 _AsyncAwaitCompleter.complete (dart:async/runtime/libasync_patch.dart:28:18)
#15 _completeOnAsyncReturn (dart:async/runtime/libasync_patch.dart:294:13)
#16 RunCommand.usageValues (package:flutter_tools/src/commands/run.dart)
#17 _asyncThenWrapperHelper.<anonymous closure> (dart:async/runtime/libasync_patch.dart:77:64)
#18 _rootRunUnary (dart:async/zone.dart:1132:38)
#19 _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#20 _FutureListener.handleValue (dart:async/future_impl.dart:126:18)
#21 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:639:45)
#22 Future._propagateToListeners (dart:async/future_impl.dart:668:32)
#23 Future._complete (dart:async/future_impl.dart:473:7)
#24 _SyncCompleter.complete (dart:async/future_impl.dart:51:12)
#25 _AsyncAwaitCompleter.complete.<anonymous closure> (dart:async/runtime/libasync_patch.dart:33:20)
#26 _rootRun (dart:async/zone.dart:1124:13)
#27 _CustomZone.run (dart:async/zone.dart:1021:19)
#28 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:947:23)
#29 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#30 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#31 _runPendingImmediateCallback (dart:isolate/runtime/libisolate_patch.dart:115:13)
#32 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:172:5)