Any object with more than two levels is truncated

[MetRonnie]

Type: Bug

Behaviour

Clicking "Copy value" in the variables context menu leads to the presented object being copied as-is, i.e. truncated.

I have tested the JS debugger and it does not exhibit the same behaviour.

Steps to reproduce:

1. Right-click a variable and click "Copy value"
2. Paste somewhere

For example, trying to copy this dictionary:

leads to the clipboard containing this ellipsis

{'hold': {'result': [...]}}

instead of the actual dictionary.

Diagnostic data

launch.json configuration

    "launch": {
        "version": "0.2.0",
        "configurations": [
            {
                "name": "Python: localhost attach",
                "type": "debugpy",
                "request": "attach",
                "justMyCode": false,
                "connect": {
                    "host": "localhost",
                    "port": 6678
                },
                "pathMappings": [
                    {
                        "localRoot": "${workspaceFolder}",
                        "remoteRoot": "${workspaceFolder}"
                    }
                ],
            },
            {
                "name": "Python: Debug Tests",
                "type": "debugpy",
                "request": "launch",
                "program": "${file}",
                "purpose": ["debug-test"],
                "justMyCode": false
              }
        ],
        "compounds": []
    },

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

N/A

Output for Python Debugger in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python Debugger)

N/A

Extension version: 2024.14.0
VS Code version: Code 1.96.2 (fabdb6a30b49f79a7aba0f2ad9df9b399473380f, 2024-12-19T10:22:47.216Z)
OS version: Linux x64 5.14.0-503.21.1.el9_5.x86_64
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.6
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Conda

System Info

Item	Value
CPUs	AMD EPYC 7763 64-Core Processor (4 x 0)
GPU Status	2d_canvas: unavailable_software canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: disabled_software multiple_raster_threads: enabled_on opengl: disabled_off rasterization: disabled_software raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: disabled_software video_encode: disabled_software vulkan: disabled_off webgl: unavailable_software webgl2: unavailable_software webgpu: disabled_off webnn: unavailable_software
Load (avg)	2, 1, 2
Memory (System)	15.32GB (6.89GB free)
Process Argv
Screen Reader	no
VM	0%
DESKTOP_SESSION	gnome
XDG_CURRENT_DESKTOP	GNOME
XDG_SESSION_DESKTOP	undefined
XDG_SESSION_TYPE	x11

[rchiodo]

I believe this is by design. Copy in the debugger copies the __repr__ of the variable. It just evals the variable so it ends up with the same thing that the variable view shows.

[rchiodo]

If you want more to be displayed, you have to change the __repr__ for the stuff in the dictionary.

Something like this:

class A():
    def __init__(self):
        self.a = 1
        self.b = 2
        self.c = 3

    def __repr__(self):
        return f"A(a={self.a}, b={self.b}, c={self.c})"

a = A()
dict = {"a": a, "b": list}
print(dict)

[rchiodo]

Can you share your code? It seems weird that you'd get '[...]' in the value for a variable unless it was really deep into iteration. At the first level I don't think it should show just ....

I'm thinking maybe the problem here isn't copying but rather the gathering of the value itself.

[MetRonnie]

The object in question is solely built-ins all the way down. The variable was created by using json.loads(). The full dictionary is like this:

{
    'hold': {
        'result': [{'success': True, 'id': 'a5bf34'}]
    }
}

I can reproduce this with a simple file run in the debugger:

[rchiodo]

It comes down to this constant here:

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

Line 33 in 40a471e

maxcollection = (60, 20)

If an object is more than two levels deep (the size of the tuple), it just truncates it. This seems unnecessary to me but changing it could affect the perf of a lot of stuff.

Maybe we'd need a setting to allow this to be controlled by the user.

[MetRonnie]

I have no objection to the representation in the debug panel being truncated, by the way. It's just that it's not useful that when you copy it, it doesn't copy the whole object

[rchiodo]

Changing the copy eval to use a different truncation might be possible. On the eval for the copy we get a 'clipboard' context.

That seems like it would be hard to know it's going to behave that way though. It would just be more information for some reason. And it might be slow too if we always had the clipboard eval expand everything.

I think I'd want a way for the user to specify how much data we expand.

[gramster]

Potentially a duplicate of issue(s): #1644