Terminal: Auto-activation command injected before shell prompt initializes

[koolcandy]

When opening a new integrated terminal in a workspace with a Python virtual environment (created by uv), the Python extension injects the activation command (source .../activate.fish) into the PTY buffer too early.

It happens before the Fish shell and the Starship prompt have fully initialized. This causes the activation command to be printed to the screen without a command prompt, leading to a messy, confusing visual experience, and sometimes causing duplicate prompt renderings.
Steps to Reproduce

• Create a Python virtual environment in a workspace using uv (e.g., uv venv).

• Open the workspace in VS Code.

• Open a new Integrated Terminal.

Expected behavior

The Python extension should wait for the shell integration/prompt to fully load before injecting the command, OR ideally, use the Environment Variable Collection to activate the uv environment silently in the background without injecting raw text into the terminal.
Actual behavior

The source /path/to/.venv/bin/activate.fish command is injected blindly into the stdin buffer. The terminal echoes this command before the Starship prompt has time to render, making it look like a broken shell state.
Environment data

• VS Code version: 1.109.5

• Python Extension version: 2026.2.0

• OS: macOS Tahoe 26.3 (arm64, Apple M1 Pro)

• Shell: fish 4.5.0

• Prompt: Starship

• Python Env Manager: uv

[anthonykim1]

Hi @koolcandy Thank you for filing the issue.

Have you tried out the shellStartup activation? This way terminal gets activated without having to send activation command to the terminal. Please try this out and let me know!

Please set python-envs.terminal.autoActivationType to shellStartup in your settings.

[koolcandy]

Hi @koolcandy Thank you for filing the issue.

Have you tried out the shellStartup activation? This way terminal gets activated without having to send activation command to the terminal. Please try this out and let me know!

Please set python-envs.terminal.autoActivationType to shellStartup in your settings.

Thank you for the suggestion. I have updated my settings to "python-envs.terminal.autoActivationType": "shellStartup" as requested (see the attached screenshot).

However, even with this setting, VS Code still sends the explicit activation command to the terminal:
source /path/to/.venv/bin/activate.fish

Is there any additional configuration required for Fish shell to support variable-based activation, or is this a known limitation for this shell type?

[koolcandy]

Hi @koolcandy Thank you for filing the issue.

Have you tried out the shellStartup activation? This way terminal gets activated without having to send activation command to the terminal. Please try this out and let me know!

Please set python-envs.terminal.autoActivationType to shellStartup in your settings.

I’ve noticed that the shellStartup behavior only applies to the initial terminal opened immediately after a VS Code restart. However, any subsequent new terminals I create seem to fall back to the command-based activation mode

[koolcandy]

After upgrade vscode, it fixed.