Suggestion: child process debugging support

[gregg-miskelly]

Description

Currently, there is no way for a debugger to automatically debug child .NET processes on all platforms. On Windows + Visual Studio, there is the Child Process Debugging Power Tool but we don't have an answer for non-Windows.

Proposal:

1. Add a new ICorDebug API to allow a debugger to opt-into notification of when child processes are started. If enabled, the notification should fire when the new process exists, but before it can run any .NET Code.
2. Modify implementation of System.Diagnostics.Process.Start (and other prominent places where the runtime starts processes, in case some stuff uses some other API) to make the following change to process starting when there is an attached debugging which has opted into the new notification
   • Start the new process suspended (ex: use CREATE_SUSPENDED on Windows, or the equivalent PAL functionality)
   • Fire the notification to the debugger
   • Resume the new process after the debugger continues execution
3. The notification should contain the following information:
   • The new process id
   • The new application executable, or maybe the logical executable (ex: foo.dll instead of dotnet.exe)
   • Perhaps the command line of the new process

[ghost]

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[rohanrhu]

MS you are a trillion dollars company why does this very important missing feature stay here forever?