hot reload doesn't work when stopped at a breakpoint

[skybrian]

To reproduce:

• create a new Flutter project
• set a breakpoint at _counter++;
• launch in debugger
• press button to stop at breakpoint
• press hot reload icon

At this point, a background task spins: "Intializing hot reload..." and that Flutter app is still frozen. Pressing "Resume Program" doesn't help.

A message is logged:

[ 984658]   WARN - o.flutter.run.daemon.DaemonApi - Flutter process returned an error: {"id":1,"error":"TimeoutException: Request to Dart VM Service timed out: _flutter.listViews({})"} 

Versions:

Flutter plugin at HEAD,

$ flutter --version
Flutter • channel master • https://github.com/flutter/flutter.git
Framework • revision 1d6a8249f8 (4 days ago) • 2017-04-27 13:34:48 -0700
Engine • revision c0f1e3b47b
Tools • Dart 1.23.0-dev.11.11

[devoncarew]

This has been working. My guess here is that we could bisect this to a commit in flutter_tools, which introduces a call to listViews(), or changes the timing of when it's called.

[skybrian]

I tried some different flutter SDK versions.

Broken with:
head ffa8483f3b4d7be09e6d4e5076c580a7780e3b62
12 days ago: 311d35354a94c51a9a21375d713e6e5b24001682

Works:
13 days ago: 2cf50ce574e71275d76acf37f6879ca457ecd0ce - seems related
14 days ago: fc58bd76792f746546162d5b98351bcb8dc75626
17 days ago: c4482b4ace6d048a16ad07461f111533485a4565
24 days ago: 5b89c10105a929aea7ed72e1d9d742ba1af90f3c
a month ago: ab6df3af40495c00f5a56013edecc212877d0d08

[skybrian]

The culprit seems to be: flutter/flutter@71d80fb

Reverting it fixes the bug.

[devoncarew]

Good find. We shouldn't call refreshViews() if we're paused. There already code (a bit further down in that method) that checks the pause state.