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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"python-xlib fails to parse X server Visual/Depth info on Void Linux (Python 3.11/3.13)","articleBody":"### Bug Report: `python-xlib` fails to retrieve standard X server Visual/Depth information\n\n**Description:**\nI am encountering a persistent and unusual issue where `python-xlib` (both 0.33 and 0.29) on Void Linux (using Python 3.13 and Python 3.11) is unable to properly retrieve and expose X server visual and depth information, leading to `AttributeError` on expected properties and an inability to find the default visual in `screen.allowed_depths`.\n\nMy X server is functioning normally and reports standard visual information via `xdpyinfo`.\n\n**Environment:**\n* **Operating System:** Void Linux (x86_64)\n* **Python Version (tested):** Python 3.13.0) and Python 3.11.12_2\n* **`python-xlib` Version (tested):** 0.33 and 0.29\n* **X Server:** \"Xorg\" \n* **Desktop Environment/Window Manager:** Openbox\n\n**Steps to Reproduce:**\n1.  Create a Python virtual environment (tested with both Python 3.13 and Python 3.11).\n2.  Install `python-xlib==0.33` (then later tried 0.29) into the environment:\n    `pip install python-xlib==0.33` (then `pip install python-xlib==0.29`)\n3.  Ran Python script `test_xlib.py` to check basic `screen` properties.\n4.  Ran Python script `center_dot.py` which attempts to find and use the default visual.\n\n**Expected Behavior:**\nThe `python-xlib` library should successfully access properties like `screen.default_visual`, `screen.default_depth`, `root.get_geometry().visual`, and `visual_obj.id` within `screen.allowed_depths`. It should be able to identify and use the default visual (0x20 / 32) and depth (24) reported by `xdpyinfo`.\n\n**Actual Behavior / Error Messages:**\n\n\n---\n**1. Output from `test_xlib.py` (with python-xlib 0.33):**\n\nSuccessfully connected to X server.\nScreen width: 1920\nScreen height: 1080\nRoot visual ID (screen.root_visual): 32\nRoot depth (screen.root_depth): 24\nAttributeError trying to get screen properties: get_visual_from_id\nThis indicates a deep issue with python-xlib's interaction with your X server.\nDisconnected from X server.\n\n**2. Output from `center_dot.py` (after attempts with `getattr` workaround, python-xlib 0.33, Python 3.13):**\nCRITICAL: Could not find a matching Visual object for ID 32 and depth 24. Exiting.\n\n*(Note: This occurred after the `AttributeError: id` was bypassed by `getattr`.)*\n\n**3. Output from `center_dot.py` (with python-xlib 0.29, Python 3.11):**\n\nWarning: 'screen.default_visual' or 'screen.default_depth' not found directly. Falling back to root geometry.\nTraceback (most recent call last):\nFile \"/home/XXX/pyxdg_env_py311/lib/python3.11/site-packages/Xlib/protocol/rq.py\", line 1294, in getattr\nreturn self._data[attr]\n~~~~~~~~~~^^^^^^\nKeyError: 'default_visual'\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\nFile \"/home/XXXX/python_scripts/center_dot.py\", line 34, in create_centered_dot_overlay\nselected_visual = screen.default_visual\n^^^^^^^^^^^^^^^^^^^^^\nFile \"/home/XXXX/pyxdg_env_py311/lib/python3.11/site-packages/Xlib/protocol/rq.py\", line 1298, in getattr\nraise AttributeError(attr)\nAttributeError: default_visual\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\nFile \"/home/XXXX/pyxdg_env_py311/lib/python3.11/site-packages/Xlib/protocol/rq.py\", line 1294, in getattr\nreturn self._data[attr]\n~~~~~~~~~~^^^^^^\nKeyError: 'visual'\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\nFile \"/home/XXXX/python_scripts/center_dot.py\", line 144, in \u0026lt;module\u003e\ncreate_centered_dot_overlay()\nFile \"/home/XXXX/python_scripts/center_dot.py\", line 41, in create_centered_dot_overlay\nif isinstance(geometry.visual, int):\n^^^^^^^^^^^^^^^\nFile \"/home/XXXX/pyxdg_env_py311/lib/python3.11/site-packages/Xlib/protocol/rq.py\", line 1298, in getattr\nraise AttributeError(attr)\nAttributeError: visual\n\n**4. Output from `xdpyinfo | grep -E \"visual|depths\"` (showing correct X server data):**\n\ndepths (7):     24, 1, 4, 8, 15, 16, 32\nnumber of visuals:    156\ndefault visual id:  0x20\nvisual:\nvisual id:      0x20\n\n**5. Python Script `test_xlib.py` (as provided earlier):**\n\n```python\n# ~/python_scripts/test_xlib.py\n#!/usr/bin/env python3\nimport Xlib.display\nimport Xlib.X\n\ntry:\n    display = Xlib.display.Display()\n    screen = display.screen()\n    root = screen.root\n\n    print(\"Successfully connected to X server.\")\n    print(f\"Screen width: {root.get_geometry().width}\")\n    print(f\"Screen height: {root.get_geometry().height}\")\n\n    try:\n        print(f\"Root visual ID (screen.root_visual): {screen.root_visual}\")\n        print(f\"Root depth (screen.root_depth): {screen.root_depth}\")\n\n        # This is the line that failed last:\n        test_visual_object = screen.get_visual_from_id(screen.root_visual)\n        print(f\"Got visual object from ID. Its ID is: {test_visual_object.id}\")\n\n    except AttributeError as e:\n        print(f\"AttributeError trying to get screen properties: {e}\")\n        print(\"This indicates a deep issue with python-xlib's interaction with your X server.\")\n    except Exception as e:\n        print(f\"An unexpected error occurred while getting screen properties: {e}\")\n\n    display.close()\n    print(\"Disconnected from X server.\")\n\nexcept Xlib.error.DisplayNameError:\n    print(\"ERROR: Cannot open display. Is X server running and DISPLAY environment variable set?\")\nexcept Exception as e:\n print(f\"An unexpected error occurred during Xlib initialization: {e}\")\n\n# ~/python_scripts/center_dot.py\n#!/usr/bin/env python3\nimport Xlib.display\nimport Xlib.X\nimport Xlib.protocol.event\nfrom Xlib.ext import xfixes\nimport time\n\ndef create_centered_dot_overlay():\n    display = Xlib.display.Display()\n    screen = display.screen()\n    root = screen.root\n\n    screen_width = root.get_geometry().width\n    screen_height = root.get_geometry().height\n    center_x = screen_width // 2\n    center_y = screen_height // 2\n\n    TARGET_VISUAL_ID_DEC = 32\n    TARGET_DEPTH = 24\n\n    selected_visual = None\n    found_depth = None\n\n    print(f\"Searching for visual ID {TARGET_VISUAL_ID_DEC} with depth {TARGET_DEPTH}...\")\n    for depth_info in screen.allowed_depths:\n        print(f\"  Checking depth: {depth_info.depth}\")\n        if depth_info.depth == TARGET_DEPTH:\n            for visual_obj in depth_info.visuals:\n                visual_id_val = getattr(visual_obj, 'id', None)\n                if visual_id_val is not None and visual_id_val == TARGET_VISUAL_ID_DEC:\n                    selected_visual = visual_obj\n                    found_depth = depth_info.depth\n                    print(f\"  --\u003e Found matching visual: ID {selected_visual.id}, Depth {found_depth}\")\n                    break\n            if selected_visual:\n                break\n\n    if selected_visual is None:\n        print(f\"CRITICAL: Could not find a matching Visual object for ID {TARGET_VISUAL_ID_DEC} and depth {TARGET_DEPTH} within screen.allowed_depths. Exiting.\")\n        print(\"This indicates a severe incompatibility or issue with your python-xlib installation or X server configuration.\")\n        display.close()\n        exit(1)\n\n    print(f\"Using visual ID: {selected_visual.id} with depth: {found_depth}\")\n    print(\"Transparency might not work without a compositing manager (Picom/Compton) and a suitable visual.\")\n\n    window = root.create_window(\n        0, 0, screen_width, screen_height, 0,\n        found_depth,\n        Xlib.X.InputOutput,\n        selected_visual,\n        Xlib.X.CWBackPixel | Xlib.X.CWEventMask | Xlib.X.CWOverrideRedirect | Xlib.X.CWColormap,\n        {\n            'background_pixel': 0,\n            'event_mask': Xlib.X.ExposureMask,\n            'override_redirect': True,\n            'colormap': display.create_colormap(root, selected_visual, Xlib.X.AllocNone)\n        }\n    )\n\n    NET_WM_STATE = display.intern_atom('_NET_WM_STATE')\n    _NET_WM_STATE_ABOVE = display.intern_atom('_NET_WM_STATE_ABOVE')\n    window.change_property(\n        Xlib.X.ChangePropertyModeReplace,\n        NET_WM_STATE,\n        Xlib.display.None_,\n        32,\n        [_NET_WM_STATE_ABOVE]\n    )\n    event = Xlib.protocol.event.ClientMessage(\n        window=window,\n        client_type=NET_WM_STATE,\n        data=(32, (_NET_WM_STATE_ABOVE, 1, 0, 0, 0))\n    )\n    root.send_event(event, Xlib.X.SubstructureNotifyMask | Xlib.X.SubstructureRedirectMask)\n\n    empty_region = xfixes.create_region(display)\n    xfixes.set_window_shape_region(display, window.id, Xlib.X.ShapeInput, 0, 0, empty_region)\n    empty_region.free()\n\n    window.map_window()\n    display.sync()\n\n    dot_color = screen.black_pixel\n    gc = window.create_gc(\n        foreground=dot_color,\n        function=Xlib.X.GXcopy\n    )\n\n    try:\n        while True:\n            event = display.next_event()\n            if event.type == Xlib.X.Expose:\n                dot_size = 3\n                window.fill_arc(gc, center_x - dot_size, center_y - dot_size,\n                                dot_size * 2, dot_size * 2, 0, 360 * 64)\n                display.flush()\n            time.sleep(0.01)\n    except KeyboardInterrupt:\n        print(\"\\nExiting dot overlay.\")\n    finally:\n        gc.free()\n        window.destroy()\n        display.close()\n\nif __name__ == \"__main__\":\n    create_centered_dot_overlay()\n\n\nxdpyinfo shows correct X server data.\nattempted different python-xlib versions and Python interpreter versions without success.\nissue isolated to python-xlib's internal handling of X server responses.\n","author":{"url":"https://github.com/Schaekker","@type":"Person","name":"Schaekker"},"datePublished":"2025-06-02T16:17:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/282/python-xlib/issues/282"}