fix: skip terminal activation when there is no activate script

[Shubham Padkonde (Shubham-Padkonde)]

Fixes #1775

Problem

When an interpreter's bin/ has no activate script, getShellActivationCommands(binDir) still emitted source <bin>/activate for sh, bash, zsh, Git Bash, ksh and the unknown fallback. uv python install toolchains are an example: they're base interpreters, not virtual environments. Every new terminal then ran a failing command:

source: no such file or directory: ~/.local/share/uv/python/cpython-3.13.9-macos-aarch64-none/bin/activate

The other shells (csh, fish, xonsh, nu, pwsh, cmd) were already gated on their script existing.

Fix

• getShellActivationCommands only adds the activate-based entries (unknown, sh, bash, Git Bash, zsh, ksh) when <binDir>/activate exists. This matches how the other shells are handled. Real venvs, pipenv and poetry environments always ship activate, so they're unaffected.
• isActivatableEnvironment now requires a non-empty shellActivation map. It used to check only that the map existed, so an environment with no activation commands was still offered for activation (the terminal activate button and command-based auto-activation).

Tests

• New tests in utils.getShellActivationCommands.unit.test.ts:
  • no POSIX or unknown activation without an activate script, on non-Windows and on Windows;
  • activation is still emitted when the script exists.
• New src/test/features/common/activation.unit.test.ts covers isActivatableEnvironment, including the empty-map case.
• Two existing tests ("Bash activation does not include Set-ExecutionPolicy" and "Windows unknown shell uses activate…") now create the activate file they rely on.
• Unit tests (tsc + mocha, Node 22):
  • with the change: 2411 passing;
  • without it: the 3 new tests covering the bug fail.
• eslint and prettier --check are clean on the changed files.

I did not test this manually in VS Code with a real uv toolchain. The fix is covered by the unit tests above.

This change was written with help from an AI coding assistant (Claude Code). I reviewed and tested it as described above.

🤖 Generated with Claude Code