Python venv not automatically activating when clicking the Play button

[tobschndr]

Type: Bug

Description: When running a Python script in VS Code, the virtual environment (venv) is not automatically activated, even though the interpreter is correctly selected. In the lower window, I see the interpreter "3.12.8 ('.venv': venv)", but when clicking the Play button, the venv is not activated (it does not appear in green as (venv) in the terminal).

Steps to Reproduce:

1. Create a new project in VS Code.
2. Create a virtual environment (venv) with python -m venv .venv.
3. Select the interpreter "3.12.8 ('.venv': venv)".
4. Open a Python script and click the Play button.

Expected Behavior:
The terminal should automatically activate the virtual environment (venv), and "(venv)" should appear in green in the terminal.

Actual Behavior:
The terminal does not automatically activate the virtual environment (venv), and "(venv)" does not appear in the terminal.
BUT: There is a hint shown by VS Code that it is activated even when not showing.

BUT: when then running a script, use the same terminal to install a pip package...it will be installed to the global environment, not to the "activated" venv

Additional Configuration Done:

1. Go to File > Preferences and search for Terminal > Integrated: Enable Persistent Settings. Ensure this option is enabled.
2. Search for Python > Terminal: Activate Environment in Current Terminal and ensure this option is enabled.
3. Search for Python > Terminal: Activate Environment (in all terminals) and ensure this option is enabled

Extension version: 2024.23.2024121801
VS Code version: Code 1.96.0 (138f619c86f1199955d53b4166bef66ef252935c, 2024-12-11T02:29:09.626Z)
OS version: Windows_NT x64 10.0.22631
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.8
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

terminal
• executeInFileDir: "<placeholder>"

Installed Extensions

Extension Name	Extension Id	Version
black-formatter	ms-	2024.5.13171011
copilot	Git	1.252.1270
copilot-chat	Git	0.23.2024102903
debugpy	ms-	2024.15.2024121701
js-debug	ms-	1.96.0
js-debug-companion	ms-	1.1.3
json	Zai	2.0.2
jupyter	ms-	2025.1.2024121801
jupyter-keymap	ms-	1.1.2
powershell	ms-	2024.4.0
python	ms-	2024.23.2024121801
python-environment-manager	don	1.2.4
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-language-pack-de	MS-	1.96.2024121109
vscode-pylance	ms-	2024.12.100
vscode-xml	red	0.27.2024121308
vscode-yaml	red	1.15.0
vscodeintellicode	Vis	1.3.2

[karthiknadig]

Can you try disabling the following experiment?

"python.experiments.optOutFrom": ["pythonTerminalEnvVarActivation"]

You will have to reload VS Code to get state to revert.

[tobschndr]

@karthiknadig : Thank you for your prompt support. It seems to have solved my issue. After setting this parameter in the workspace settings and reloading VS Code, it now opens with the (venv) activated, even in the previously open terminals. Closing them and clicking the Play button also results in the desired situation.