Flutter was working just fine a few weeks ago, however it appears to be broken on my system. I cleaned my existing install and re-cloned and installed flutter, but it seems to fail with the following problem:
Akshays-MacBook-Pro-2:~ akshaydashrath$ flutter doctor
Downloading Dart SDK 1.21.0...
#################################################################100.0%
Building flutter tool...
vm-service: Error: Unhandled exception:
Unsupported operation: Cannot extract a non-Windows file path from a
file URI with an authority
#0 _SimpleUri._toFilePath (dart:core/uri.dart:4423)
#1 _SimpleUri.toFilePath (dart:core/uri.dart:4417)
#2 _loadFile (loader.dart:407:26)
#3 _handleResourceRequest (loader.dart:510:5)
#4 _processLoadRequest (loader.dart:941:7)
#5 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:148)
I've recently updated MacOS to 10.12.2 apart from that I can't identify any other changes I've made that could affect the system.
This turned out to be an issue with akshaydashrath's $PATH having an extra leading // in the path to FLUTTER_SDK/bin directory. Unclear yet if it's a Dart bug or Flutter bug or both, the fix is being tracked by https://github.com/flutter/flutter/issues/7279.
If anyone were to hit this again, the resolution is to check your PATH and make sure it doesn't have an extra leading
/in your//path/to/flutter/bin.