Created attachment 113952 [details]
Project scanning blocking debugger start.
Until the project scan completes, it's not possible to start debugging.
This occurs when there are breakpoints submitted. The start of the debugger is blocked by identification of classes in debugger's sources.
It's apparent from the attached thread dump.
This matters only when Compile on Save is off. Otherwise Run and Debug actions wait for project scan & build.
When submitting breakpoints to the starting debuggee, it's necessary to be able to check the class names in the debug sources. The performance should be improved by using shared task, it is not blocked by the full scanning now.
Integrated into 'main-golden'
Log: #206137 Use shared task to improve performance.