(regression) Typing causes high CPU usage

[irm-codebase]

Type: Bug

Behaviour

Typing anything in python will result in high resource usage not seen in previous versions of this software.
If you are decently fast at typing code, you'll hear your poor CPU complain about the stress seemingly innocuous text places upon it.

This has been tested with all other extensions disabled except for:

• Pylance
• Python
• Python debugger
• Python environments

Steps to reproduce:

1. With the latest release (1.102.3)
2. Use a relatively large python file (1000+ lines). A test file is a good case for this.
3. Anywhere in the file, spam text. Look at your system's CPU usage.
4. Watch those lines go up, and not in a good way!

Screencast.From.2025-08-06.11-22-37.mp4

Diagnostic data

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

XXX

Extension version: 2025.10.1
VS Code version: Code 1.102.3 (488a1f239235055e34e673291fb8d8c810886f81, 2025-07-29T03:00:23.339Z)
OS version: Linux x64 6.15.8-200.fc42.x86_64
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.11
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Conda
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

experiments
• enabled: false

Installed Extensions

Extension Name	Extension Id	Version
debugpy	ms-	2025.10.0
js-debug	ms-	1.102.0
js-debug-companion	ms-	1.1.3
python	ms-	2025.10.1
vscode-js-profile-table	ms-	1.0.10
vscode-pylance	ms-	2025.7.1
vscode-python-envs	ms-	1.2.0

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13700H (20 x 3700)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off webnn: disabled_off
Load (avg)	2, 1, 1
Memory (System)	15.25GB (7.10GB free)
Process Argv
Screen Reader	no
VM	0%
DESKTOP_SESSION	gnome
XDG_CURRENT_DESKTOP	GNOME
XDG_SESSION_DESKTOP	gnome
XDG_SESSION_TYPE	wayland

[irm-codebase]

The culprit seems to be Pylance.
I've also created a look-alike here microsoft/pylance-release#7486

[rchiodo]

Closing as a dupe of the other issue