Python extension activates virtual environment twice / delayed activation interrupts terminal input

[philhanna]

Type: Bug

Summary

When opening a terminal in VS Code with Python extension enabled, the virtual environment activation:

1. Happens with a delay (a few seconds)
2. Sometimes runs twice
3. Interrupts user input if typing has already started

This makes the terminal unreliable and feels like a race condition.

Steps to Reproduce

1. Open a workspace with a .venv
2. Ensure Python interpreter is set to that venv
3. Open a new terminal
4. Immediately start typing

Expected Behavior

• Environment activates immediately OR deterministically before input
• Activation runs exactly once
• No interruption of user input

Actual Behavior

• Activation occurs after a delay
• Sometimes runs twice
• Interrupts typing (inserts activation command mid-input)

Settings

Example settings:

{
"python-envs.terminal.autoActivationType": "command",
"python.terminal.activateEnvInCurrentTerminal": true
}

(Also observed with default settings)

Environment

• VS Code version:
• Python extension version:
• OS: (Linux / Windows / macOS)
• Shell: (bash, zsh, etc.)

Additional Notes

This appears related to multiple activation mechanisms:

• python-envs.terminal.autoActivationType
• python.terminal.activateEnvironment
• python.terminal.activateEnvInCurrentTerminal

Possibly a race condition between extension activation and terminal creation.

PYTHON SHOW OUTPUT:
2026-03-17 19:43:38.307 [info] Native locator: Refresh started
2026-03-17 19:43:38.555 [info] Native locator: Refresh started
2026-03-17 19:43:38.763 [info] VS Code was launched from an activated environment: 'venv', selecting it as the interpreter for workspace.
2026-03-17 19:43:38.800 [info] Native locator: Refresh finished in 596 ms
2026-03-17 19:43:39.180 [info] Native locator: Refresh started
2026-03-17 19:43:39.182 [info] Python interpreter path: ./venv/bin/python
2026-03-17 19:43:39.205 [info] Active interpreter [/home/saspeh/today/2026-03-17/cword]: /home/saspeh/today/2026-03-17/cword/venv/bin/python
2026-03-17 19:43:39.765 [info] Native locator: Refresh finished in 585 ms
2026-03-17 19:43:39.799 [info] > pyenv which python
2026-03-17 19:43:39.799 [info] cwd: .
2026-03-17 19:43:41.998 [info] Starting Pylance language server.
2026-03-17 19:45:50.797 [info] Native locator: Refresh started
2026-03-17 19:45:50.851 [info] Native locator: Refresh finished in 495 ms
2026-03-17 19:45:50.852 [info] VS Code was launched from an activated environment: 'venv', selecting it as the interpreter for workspace.
2026-03-17 19:45:51.018 [info] Python interpreter path: ./venv/bin/python
2026-03-17 19:45:51.296 [info] > pyenv which python
2026-03-17 19:45:51.296 [info] cwd: .
2026-03-17 19:45:53.515 [info] Starting Pylance language server.

My thoughts

This feels like a race condition between terminal startup and extension activation.

Extension version: 2026.4.0
VS Code version: Code 1.111.0 (ce099c1ed25d9eb3076c11e4a280f3eb52b4fbeb, 2026-03-06T23:06:10Z)
OS version: Linux x64 6.8.0-106-generic
Modes:

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

User Settings

languageServer: "Pylance"

Installed Extensions

Extension Name	Extension Id	Version
autodocstring	njp	0.6.1
autopep8	ms-	2025.2.0
black-formatter	ms-	2025.2.0
cmake	twx	0.0.17
cmake-tools	ms-	1.22.28
copilot-chat	Git	0.39.2
cpp-devtools	ms-	0.3.6
cpptools	ms-	1.30.5
cpptools-extension-pack	ms-	1.5.1
cpptools-themes	ms-	2.0.0
debugpy	ms-	2025.18.0
docker	doc	0.18.0
even-better-toml	tam	0.21.2
go	gol	0.52.2
java	red	1.53.0
jinja	who	0.0.8
js-debug	ms-	1.110.0
js-debug-companion	ms-	1.1.3
language-j	tik	0.9.6
live-server	ms-	0.4.17
LiveServer	rit	5.7.10
open-in-vim	jon	0.7.0
pdf	tom	1.2.2
python	ms-	2026.4.0
python-docs	Muk	0.8.3
python-environment-manager	don	1.2.7
python-extension-pack	don	1.7.0
rainbow-csv	mec	3.24.1
remote-containers	ms-	0.447.0
scala	sca	0.5.9
sqlite-viewer	qwt	25.12.2
test-adapter-converter	ms-	0.2.1
todo-tree	Gru	0.0.226
vsc-python-indent	Kev	1.21.0
vscode-containers	ms-	2.4.1
vscode-django	bat	1.15.0
vscode-docker	ms-	2.0.0
vscode-github-actions	git	0.31.0
vscode-gradle	vsc	3.17.2
vscode-java-debug	vsc	0.58.5
vscode-java-dependency	vsc	0.27.0
vscode-java-pack	vsc	0.30.5
vscode-java-test	vsc	0.44.0
vscode-js-profile-table	ms-	1.0.10
vscode-maven	vsc	0.45.1
vscode-pylance	ms-	2026.1.1
vscode-python-envs	ms-	1.22.0
vscode-python-test-adapter	lit	0.8.2
vscode-sqlite	ale	0.14.1
vscode-test-explorer	hbe	2.22.1
vscode-xml	red	0.29.0
vscode-yaml	red	1.21.0

System Info

Item	Value
CPUs	AMD Ryzen 7 5700G with Radeon Graphics (16 x 3705)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x1002 [Google Inc. (AMD)], DEVICE=0x1638 [ANGLE (AMD, AMD Radeon Graphics (radeonsi renoir ACO), OpenGL 4.6 (Core Profile) Mesa 25.2.8-0ubuntu0.24.04.1)], 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)	0, 1, 1
Memory (System)	14.96GB (9.09GB free)
Process Argv	. --crash-reporter-id 76f07ab8-e1ec-4776-ab4a-6235c73325cf
Screen Reader	no
VM	0%
DESKTOP_SESSION	ubuntu
XDG_CURRENT_DESKTOP	ubuntu:GNOME
XDG_SESSION_DESKTOP	ubuntu
XDG_SESSION_TYPE	x11

A/B Experiments

vsliv368:30146709
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
6abeh943:31336334
envsdeactivate2:31464701
cloudbuttont:31379625
aihoversummaries_f:31469309
3efgi100_wstrepl:31403338
56b7f661:31457055
use-responses-api:31390855
anonusage:31403420
ddidtcf:31399634
je187915:31401257
ec5jj548:31422691
cp_cls_t_966_ss:31454198
a9239246:31458807
4je02754:31466945
c3h7c220:31478652
ge8j1254_inline_auto_hint_haiku:31431912
38bie571_auto:31478678
7a04d226_do_not_restore_last_panel_session:31438103
preserve_tokens:31444547
cp_cls_t_1081:31454832
ia-use-proxy-models-svc:31452481
a43f0574a:31442826
e9c30283:31461165
test_treatment2:31471001
ts_provider_disabled:31458191
nes-conv-2-3:31477815
g_63ac8346:31467999
idci7584:31464702
edit_mode_hidden:31461530
864ei723_large_tool_results_to_disk:31460878
notips:31471632
ei9d7968:31458072
534a6447_copy:31478748
nes-extended-on:31455476
chat:31457767
8hig5102:31473806
ah:31460422
8a2c4887_5_3_codex_prompt:31475326
cpptoolson-v2:31475363
thinking_effort_h:31478170
4dgh1208:31471592
editor1:31474144
thinking_c:31471065
db0gd219:31473911
newsessionicon:31473927
h08i8180_copy:31475368
ddid_t:31478206

[philhanna]

Feel free to ask any further questions that would help you. Thanks very much!

[eleanorjboyd]

can you set python.useEnvsExtension to true and then make sure you have the latest version of the python environments extension installed? We just put in a fix for this problem

[philhanna]

I'm still seeing the same old behavior, but I don't know if I applied the setup you describe properly. 1. Where do I set python.useEnvsExtension to true? I updated my ~/.config/Code/User/settings.json as follows: ... "[python]": { "diffEditor.ignoreTrimWhitespace": false, "useEnvsExtension": true, *<- Inserted this line* "editor.defaultFormatter": "ms-python.black-formatter" }, ... Do I have the syntax right? strip off the "python." prefix because it's part of a block with that prefix. 2. Do I have the right extension installed? Installation Identifier ms-python.vscode-python-envs Version 1.23.10701010 Last Updated 23 minutes ago Size 37.02MB Cache 2.66KB Thanks muchly, *Phil Hanna* Email: ***@***.***

…

On Wed, Mar 18, 2026 at 6:33 PM Eleanor Boyd ***@***.***> wrote: *eleanorjboyd* left a comment (microsoft/vscode-python#25868) <#25868 (comment)> can you set python.useEnvsExtension to true and then make sure you have the latest version of the python environments extension installed? We just put in a fix for this problem — Reply to this email directly, view it on GitHub <#25868 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA4JODN23LX6VLVKJLZJXOD4RMP4DAVCNFSM6AAAAACWVWMXV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAOBVHE4TCMJQGU> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[anthonykim1]

Please set python-envs.terminal.autoActivationType to shellStartup in your settings.
Also add "python.useEnvironmentsExtension": true, to your settings.json.

Please file issue on https://github.com/microsoft/vscode-python-environments/issues if you see problem again, thanks.

Delay is We now have unified timeout for shell integration: microsoft/vscode#272369
See more descriptions here: https://code.visualstudio.com/updates/v1_106#_consolidated-shell-integration-timeout-setting

[philhanna]

Thanks, this was the fix! *Phil Hanna* Email: ***@***.***

…

On Fri, Mar 20, 2026 at 1:44 PM Anthony Kim ***@***.***> wrote: *anthonykim1* left a comment (microsoft/vscode-python#25868) <#25868 (comment)> Please set python-envs.terminal.autoActivationType to shellStartup in your settings. Also add "python.useEnvironmentsExtension": true, to your settings.json. Please file issue on https://github.com/microsoft/vscode-python-environments/issues if you see problem again, thanks. Delay is We now have unified timeout for shell integration: microsoft/vscode#272369 <microsoft/vscode#272369> See more descriptions here: https://code.visualstudio.com/updates/v1_106#_consolidated-shell-integration-timeout-setting — Reply to this email directly, view it on GitHub <#25868?email_source=notifications&email_token=AA4JODJ7I6QXXVV6XUHBD234RV7P7A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTIMBZHE4DONBXGQ2KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-4099874744>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA4JODPLWFHOYYYJFFSEC5T4RV7P7AVCNFSM6AAAAACWVWMXV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAOJZHA3TINZUGQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>