Currently, in order to attach to a process, I need to provide the following fields in my launch.json:

{
    "name" : "Attach (gdb)",
    "type" : "cppdbg",
    "request" : "attach"
    "program" : "${workspaceFolder}/path/to/program",
    "processId" : "${command:pickProcess}",
    "MIMode" : "gdb"
}

In my tests, it seems that the program field is validated (i.e. the executable exists, it is a valid executable), but it is completely ignored when debugging. I can set "program" = "/bin/bash" and attach to any process I want. But if I set "program" = "non existent file", I get a launch error that the program doesn't exist.

So why do I need to provide a path to the executable, when it is not needed?

Of course, it would be nice if ${command:pickProcess} would use this field to filter the processes, but it doesn't. Even then, it should be optional.