Add debugger data breakpoints

[TheWizier]

I would like to suggest adding the functionality to add breakpoints for value changes on variables as is available in the vscode c++ debugger (Break on Value Change)

Functionality would be: right click on variable in inspector, choose option Break on Value Change. Then when the value is changed by the program the debugger pauses.

[apholden-fds]

This feature would be very helpful for my team. Is there anything we can do to expedite it?

[elfrocampeador]

This feature would make debugging complex systems dramatically easier, and is as far as I know pretty common. I'm very interested to see this added.

[apholden-fds]

@elfrocampeador and I just found PR 91052 on the CPython repo. Might that facilitate a solution to this issue?

[rchiodo]

Thanks @apholden-fds , I think PyDict_AddWatcher might make this possible. It looks like it's native code though, so there'd have to be some communication between debugpy and native code loaded to do the watching.