Remote debug attach does not support path mapping

[rchiodo]

Following the directions here:
https://docs.microsoft.com/en-us/visualstudio/python/debugging-python-code-on-remote-linux-machines?view=vs-2019

I cannot get breakpoints to bind.

Internally debugpy is returning this:

1> [DebugAdapter] <-- R (setBreakpoints-12) [20 ms]: {"type":"response","request_seq":12,"success":true,"command":"setBreakpoints","body":{"breakpoints":[{"verified":false,"message":"Breakpoint in file that does not exist.","source":{"path":"c:\\Users\\aku91\\source\\repos\\PythonApplication3\\PythonApplication3\\test.py","sources":[],"checksums":[]},"line":7}]},"seq":15}

This really means we need path mapping for the remote machine. There was some discussion in the past of VSCodeDebugAdapterHost supporting a launch.json that could provide that mapping. Short of that, we'd have to provide that here:

PTVS/Python/Product/PythonTools/PythonTools/Debugger/DebugAdapter/DebugAdapterLauncher.cs

Line 167 in 984cd41

private static DebugAttachInfo GetTcpAttachDebugInfo(IAdapterLaunchInfo adapterLaunchInfo) {

We need to pass the attach request the path mappings like VS code does:

[rchiodo]

Note: this repros in D16 too.

[greazer]

Need to involve PM as there is potentially a UI component involved. @savannahostrowski

[int19h]

To be specific, we need to decide what the appropriate UX for defining path mappings is. In VSCode, this is done by editing launch.json directly. We could expose it in a similar manner here (which would also have a benefit of giving users access to the complete panoply of debugpy configuration knobs).

However, traditionally, PTVS used GUI dialogs to configure such things. If we do that, it should probably go into the Debugging tab in project properties, and we need to figure out how that UI will look. It's basically a list of entries, each mapping one local absolute path to one remote path; so the UI needs to provide some way to specify project-relative paths there, that would then be automatically expanded before they're handed over to debugpy (debugpy itself can't do this because it doesn't know anything about VS projects).

[int19h]

@ijoosong