Summary

Fixes native Windows local terminal execution issues discovered while running Hermes from a Windows checkout with Git Bash installed.

What changed

• Prefer Git Bash over Windows/WSL bash.exe launchers when resolving the local shell on Windows.
• Use a Windows-safe stdout drain path instead of relying on select.select() for subprocess pipes.
• Avoid waiting on inherited pipe handles from background children on Windows.
• Use taskkill /T /F for Windows process-tree termination in local execution and process registry paths.
• Add a small Git Bash compatibility shim so python3 maps to python when python3 is unavailable.
• Use Win32 process exit-code checks for recovered host PID liveness on Windows.
• Add/adjust tests for Windows shell selection, stdout draining, process recovery, and detached process killing.

Why

The existing local backend could execute commands on Windows but lose stdout because Windows pipes are not compatible with the POSIX select.select() drain loop. In this environment, LocalEnvironment.execute('echo hermes-local-test') returned returncode: 0 with empty output before the fix. The Windows PATH also resolved bash to the WSL launcher before Git Bash, which is not the shell the native Windows local backend expects.

Validation

Tested on Windows with Git Bash installed:

python -m pytest -o "addopts=" tests\tools\test_windows_compat.py tests\tools\test_base_environment.py tests\tools\test_local_tempdir.py tests\tools\test_terminal_timeout_output.py tests\tools\test_local_background_child_hang.py tests\tools\test_process_registry.py -q

Result: 86 passed.

Also ran:

python -m py_compile tools\environments\base.py tools\environments\local.py tools\process_registry.py tests\tools\test_windows_compat.py tests\tools\test_process_registry.py
git diff --check

git diff --check only reported expected CRLF conversion warnings from Git for this Windows checkout.