Allow modifying global variables from the variables panel

[Andrej730]

Environment data

• debugpy version: 1.8.13
• OS and version: Windows 11
• Python version (& distribution if applicable, e.g. Anaconda): 3.12.7
• Using VS Code or Visual Studio: VS Code 1.93.1

Actual behavior

Cursor_z3UFWwrl0Y.mp4

Expected behavior

To either prohibit editing global variable in that case as it's not editable or actually edit it.

Steps to reproduce:

1. Set breakpoint at b = 35 in the snippet below and run it.
2. Attach to Python using debugger.
3. Change c value in Variables section to 1000.
4. Step Over (F10), global variable is moved to locals and global variable value is reset.

What I've also noticed that if on step 3 I run globals()['c'] in Debug Console, it prints 0 and Variables are reset as we would be on the step 4.

c = 0

def main():
    a = 25

    import debugpy
    debugpy.listen(5678)
    debugpy.wait_for_client()

    b = 35
    print(a + b + c)

if __name__ == "__main__":
    main()

[rchiodo]

I believe this is by design. It sets the value of 'c' in the local frame. This code here:

debugpy/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_vars.py

Line 522 in 96de437

updated_globals = {}

If you want to force an eval to change a global, you have to do something like so:

globals()['c'] = 1000

[Andrej730]

But shouldn't it be not changable from UI or appear show it as local variable right away to prevent confusion?
Or it's https://github.com/microsoft/vscode-python-debugger issue?

[rchiodo]

I agree it's confusing. Right now the logic for eval doesn't take into account the parent of the value.

We do get the 'parent' for the variable though, so maybe we can tell that it's coming from the global list.

Reopening as an enhancement request.

[rchiodo]

Here's the request in this example:

D+00009.609: /handling #22 request "setVariable" from Client[1]/
             Server[1] <-- {
                 "seq": 24,
                 "type": "request",
                 "command": "setVariable",
                 "arguments": {
                     "variablesReference": 4,
                     "name": "c",
                     "value": "1000"
                 }
             }

And you can see in the scopes request, that variables reference 4 is 'globals':

D+00003.891: Server[1] --> {
                 "pydevd_cmd_id": 502,
                 "seq": 52,
                 "type": "response",
                 "request_seq": 20,
                 "success": true,
                 "command": "scopes",
                 "body": {
                     "scopes": [
                         {
                             "name": "Locals",
                             "variablesReference": 3,
                             "expensive": false,
                             "presentationHint": "locals",
                             "source": {}
                         },
                         {
                             "name": "Globals",
                             "variablesReference": 4,
                             "expensive": false,
                             "source": {}
                         }
                     ]
                 }
             }