VS Code Pixi env selection passes decorated label to --environment, causing parse failure #50

Summary

Selecting a Pixi environment in VS Code fails because the extension passes a decorated display label (including :default and Python version) into the CLI --environment argument, instead of the raw Pixi environment name.

Reproducible error

From Pixi Code output (repeated on 2026-09-08):

Failed to run "pixi list --no-install --frozen --json --environment "compneuro:default (3.12.14)""

Error: Cannot resolve tree item for element 0/0:compneuro/0:Python 3.14 (64-bit) from extension ms-python.vscode-python-envs

Expected behavior

The extension should pass only the canonical env name (e.g., compneuro) to --environment.

Actual behavior

The extension appears to pass a UI label string:

• compneuro (env name)
  

• :default (marker)
  

• (3.12.14) (version metadata)
  

So CLI receives: --environment "compneuro:default (3.12.14)" which Pixi rejects.

Additional correlated errors

At the same time, VS Code logs repeatedly show:

'Error: Cannot resolve tree item for element 0/0:compneuro/0:Python 3.14 (64-bit) from extension ms-python.vscode-python-envs'

This may indicate environment-label handling/parsing issues across the env provider/selector boundary.

Steps to reproduce

1. Open workspace with Pixi env compneuro.
2. In VS Code, select the Pixi env from interpreter/environment picker.
3. Observe invocation of: pixi list --no-install --frozen --json --environment "compneuro:default (3.12.14)"
4. Command fails with environment-name parse error.

Environment

OS: Windows 11 x64 (Windows_NT 10.0.26200)
VS Code: 1.136.2
Commit 88e44fa0e00b08f7758b4f6d05632e4fd5e4df6f
Date 2026-09-04T21:40:42Z
Pixi Code extension: 0.2.0
Pixi CLI: 0.79.0
Python env extension: ms-python.vscode-python-envs 1.36.0
Pylance: 2026.3.1
Workspace trust state: saw Cannot launch a terminal process in an untrusted workspace (possibly relevant)

Possible root cause

A display label is being used directly as the CLI identifier without normalization/mapping to canonical Pixi env name.

Suggested fix

Keep display metadata for UI only, and pass canonical env name to CLI calls.

Related issue

Potentially related: #13
#13