`python.testing.autoTestDiscoverOnSaveEnabled` is running test discovery on change to any file (not just test files)

[schperplata]

Type: Bug

Behaviour

Python test discovery is run on change to any ".py" file, even non-test files. Previously, test discovery seems to run only if any "test_*" files changed, but now, any opened ".py" file that has been changed triggers discovery.

I have a really large test suite, and test collection takes a couple of seconds, too much to wait it on any file save.
As a consequence, I can't use "restart debug session" (Debug: Restart) action, as save is forcibly triggering test discovery, and Debug: Restart action stops as test is shown as unknown (same icon as skipped test).

Steps to reproduce:

1. Open python source and test file.
2. Save a change in python file.
3. Check that test discovery was triggered.

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

2026-03-17 14:14:25.385 [info] [test-by-project] Cleaned up 1 test items for workspace: /home/some_code_directory
2026-03-17 14:14:25.385 [info] [test-by-project] Discovering projects for workspace: /home/some_code_directory
2026-03-17 14:14:25.385 [info] [test-by-project] Found 1 total Python projects from API
2026-03-17 14:14:25.385 [info] [test-by-project] Filtered to 1 projects in workspace
2026-03-17 14:14:25.385 [info] [test-by-project] Creating adapter for: python-information-extractors at file:///home/some_code_directory
2026-03-17 14:14:25.386 [info] [test-by-project] Registered 1 project(s) for /home/some_code_directory
2026-03-17 14:14:25.391 [info] [test-by-project] Starting discovery for 1 project(s) in workspace
2026-03-17 14:14:25.391 [info] [test-by-project] Discovering tests for project: python-information-extractors (Python 3.12)
2026-03-17 14:14:25.393 [info] arg: --rootdir already exists in args, not adding.
2026-03-17 14:14:25.393 [info] Environment variables set for pytest discovery: PYTHONPATH=/home/myusername/.vscode/extensions/ms-python.python-2026.4.0-linux-x64/python_files, TEST_RUN_PIPE=/run/user/1000/python-test-discovery-907b80b6331243033c33
2026-03-17 14:14:25.393 [info] Using environment extension for pytest discovery in workspace /home/some_code_directory
2026-03-17 14:14:25.396 [info] Started pytest discovery subprocess (environment extension) for workspace /home/some_code_directory
2026-03-17 14:14:25.851 [info] ============================= test session starts ==============================
platform linux -- Python 3.12.8, pytest-9.0.2, pluggy-1.5.0 -- /home/some_code_directory/.venv/bin/python
cachedir: .pytest_cache
rootdir: /home/some_code_directory
configfile: pyproject.toml
plugins: celery-1.2.0, pytest_docker_tools-3.1.9, cov-6.1.1, typeguard-4.4.2, xdist-3.6.1, asyncio-1.3.0, rerunfailures-15.1
asyncio: mode=Mode.STRICT, debug=False, asyncio_default_fixture_loop_scope=None, asyncio_default_test_loop_scope=function

Extension version: 2026.4.0
VS Code version: Code 1.111.0 (ce099c1ed25d9eb3076c11e4a280f3eb52b4fbeb, 2026-03-06T23:06:10Z)
OS version: Linux x64 6.17.0-19-generic
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.3.final.0
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
• Value of the python.languageServer setting: Pylance

User Settings

languageServer: "Pylance"

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

experiments
• optOutFrom: ["pythonTerminalEnvVarActivation"]

Installed Extensions

Extension Name	Extension Id	Version
black-formatter	ms-	2025.2.0
claude-code	Ant	2.1.77
code-spell-checker	str	4.5.6
code-spell-checker-slovenian	str	0.2.5
debugpy	ms-	2025.18.0
even-better-toml	tam	0.21.2
gitlens	eam	17.11.1
js-debug	ms-	1.110.0
js-debug-companion	ms-	1.1.3
markdown-all-in-one	yzh	3.6.3
mypy-type-checker	ms-	2025.2.0
open-html-in-browser	pea	2.1.10
postman-for-vscode	Pos	1.19.1
python	ms-	2026.4.0
redis-for-vscode	Red	1.4.0
ruff	cha	2026.36.0
vscode-js-profile-table	ms-	1.0.10
vscode-pylance	ms-	2026.1.1
vscode-python-envs	ms-	1.22.0
vscode-speech	ms-	0.16.0
vscode-yaml	red	1.21.0
xml	Dot	2.5.1

System Info

Item	Value
CPUs	12th Gen Intel(R) Core(TM) i7-12700H (20 x 3166)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x10de, DEVICE=0x25a0, DRIVER_VENDOR=Mesa, DRIVER_VERSION=25.2.8 GPU1: VENDOR= 0x8086, DEVICE=0x46a6, DRIVER_VENDOR=Mesa, DRIVER_VERSION=25.2.8 ACTIVE Machine model name: Machine model version: 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 trees_in_viz: disabled_off video_decode: enabled video_encode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off webnn: disabled_off
Load (avg)	1, 1, 1
Memory (System)	31.04GB (17.50GB free)
Process Argv	/home/domenj/pl_code/python-information-extractors/python-information-extractors.code-workspace --crash-reporter-id 6d211005-42ef-4cb9-9471-5fe05dfc6e5f --crash-reporter-id 6d211005-42ef-4cb9-9471-5fe05dfc6e5f
Screen Reader	no
VM	0%
DESKTOP_SESSION	ubuntu-wayland
XDG_CURRENT_DESKTOP	ubuntu:GNOME
XDG_SESSION_DESKTOP	ubuntu-wayland
XDG_SESSION_TYPE	wayland

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82j33506:31327384
6abeh943:31336334
envsactivate1:31464700
editstats-enabled:31346257
cloudbuttont:31379625
aihoversummaries_f:31469309
3efgi100_wstrepl:31403338
use-responses-api:31390855
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7a04d226_do_not_restore_last_panel_session:31438103
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test_treatment2:31471001
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edit_mode_hidden:31461530
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864ei723_large_tool_results_to_disk:31460878
notips:31471632
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chat:31457767
cpptoolsoff-v2:31475362
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noaffordance1:31474146
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commenticon:31473926
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ddid_t:31478206