Request textDocument/completion failed

[leandrodesouzadev]

Type: Bug

Behaviour

While auto-complete works on some directories of a project, auto-complete is failing on a specific directory and not provide any completions at all

Steps to reproduce:

Not really sure how to reproduce this behavior. But i'm up to provide anymore required information

Diagnostic data

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

Error while writing print on the tests directory

2025-12-17 10:02:59.899 [info] (66228): IDX(back-bid): Indexing finished(3).
2025-12-17 10:03:01.504 [info] (66228): Applying 0 edits to document file:///Users/leandro/dev/bid/back-bid/tests/test_loan/test_services/test_simulation/test_disbursed_amount_simulation.py for document transformation.
2025-12-17 10:03:01.996 [info] (66228): Applying 0 edits to document file:///Users/leandro/dev/bid/back-bid/tests/test_loan/test_services/test_simulation/test_disbursed_amount_simulation.py for document transformation.
2025-12-17 10:03:02.071 [error] Request textDocument/completion failed.
  Message: Request textDocument/completion failed with message: Cannot read properties of undefined (reading 'start')
  Code: -32603 

Extension version: 2025.20.0
VS Code version: Code 1.107.0 (Universal) (618725e67565b290ba4da6fe2d29f8fa1d4e3622, 2025-12-10T07:43:47.883Z)
OS version: Darwin arm64 25.0.0
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.7
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Pylance

User Settings

languageServer: "Pylance"

Installed Extensions

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errorlens	use	3.26.0
gitlens	eam	17.8.0
js-debug	ms-	1.105.0
js-debug-companion	ms-	1.1.3
jupyter	ms-	2025.9.1
jupyter-keymap	ms-	1.1.2
jupyter-renderers	ms-	1.3.0
material-icon-theme	PKi	5.29.0
mypy-type-checker	ms-	2025.2.0
python	ms-	2025.20.0
ruff	cha	2025.32.0
textual-syntax-highlighter	Tex	1.3.0
theme-dracula	dra	2.25.1
todo-tree	Gru	0.0.226
vscode-django	bat	1.15.0
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-pylance	ms-	2025.10.4
vscode-python-envs	ms-	1.14.0
vscode-yaml	red	1.19.1
vsliveshare	ms-	1.0.5959

System Info

Item	Value
CPUs	Apple M4 (10 x 2400)
GPU Status	2d_canvas: enabled 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: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	7, 7, 6
Memory (System)	16.00GB (0.25GB free)
Process Argv	--crash-reporter-id 68d985bb-d7c0-465f-b012-66a0486f4ee6
Screen Reader	no
VM	0%

[leandrodesouzadev]

Just found out a possible related information:
Was checking for the pylance vscode settings, and it seems to fail when the config:
Python -> Analysis: Enable Pytest Support is flagged.
The autocomplete works when outside of a function, but not inside a test function.
I have confirmed that the error happens both when the test function contains fixtures and no fixtures at all.

Disabling the Pytest Support config seems to solve the issue, but there's no completion for fixtures. For me this is not a big deal since I don't use many fixtures.