Move get_git_executable from subprocess_utils into models

[Copilot]

subprocess_utils.py was a 26-line file containing a single function — too thin to justify its own module. get_git_executable belongs in models.py, which already owns the git interaction layer and already imports shutil.

Changes

• src/rhiza/models.py — Added get_git_executable() after the existing private helpers (_log_git_stderr_errors, _normalize_to_list), before the dataclass definitions; added to __all__
• src/rhiza/commands/ — Updated imports in _sync_helpers.py, sync.py, and init.py to pull from rhiza.models
• tests/test_subprocess_utils.py — Updated import path and patch target (rhiza.subprocess_utils.shutil.which → rhiza.models.shutil.which)
• tests/test_models.py, tests/test_commands/test_sync.py — Updated all inline from rhiza.subprocess_utils import get_git_executable occurrences
• src/rhiza/subprocess_utils.py — Deleted
• docs/adr/0001-inline-get-diff-instead-of-cruft.md — Updated prose reference from subprocess_utils.get_git_executable → models.get_git_executable

Original prompt

Summary

Move get_git_executable() from src/rhiza/subprocess_utils.py into src/rhiza/models.py and delete subprocess_utils.py. It is a 26-line file containing a single function — the definition of a module that shouldn't exist as a standalone file.

Detailed changes

1. Add get_git_executable() to src/rhiza/models.py

Add import shutil to the existing imports (it is not already imported there), then add the following function at module level near the top of the file, after the existing private helpers _log_git_stderr_errors and _normalize_to_list, and before the dataclass definitions:

def get_git_executable() -> str:
    """Get the absolute path to the git executable.

    This function ensures we use the full path to git to prevent
    security issues related to PATH manipulation.

    Returns:
        str: Absolute path to the git executable.

    Raises:
        RuntimeError: If git executable is not found in PATH.
    """
    git_path = shutil.which("git")
    if git_path is None:
        msg = "git executable not found in PATH. Please ensure git is installed and available."
        raise RuntimeError(msg)
    return git_path

Also add "get_git_executable" to the __all__ list in models.py.

Note: models.py already imports shutil (it uses shutil.copy2 in _prepare_snapshot), so no new import is needed.

2. Update all import sites — replace from rhiza.subprocess_utils import get_git_executable with from rhiza.models import get_git_executable

The following files need this import updated:

• src/rhiza/commands/_sync_helpers.py (line 28)
• src/rhiza/commands/sync.py (last import line in the imports block)
• src/rhiza/commands/init.py (last import line in the imports block)
• tests/test_models.py (multiple occurrences inside test methods — all from rhiza.subprocess_utils import get_git_executable lines)
• tests/test_commands/test_sync.py (one occurrence inside a test method)

3. Migrate tests/test_subprocess_utils.py → update import and patch path

In tests/test_subprocess_utils.py, change:

• from rhiza.subprocess_utils import get_git_executable → from rhiza.models import get_git_executable
• The patch target "rhiza.subprocess_utils.shutil.which" → "rhiza.models.shutil.which"

The test class and assertions can remain identical.

4. Delete src/rhiza/subprocess_utils.py

Delete the file entirely.

Notes

• No other files are known to reference rhiza.subprocess_utils beyond those listed above (confirmed by code search).
• The ADR at docs/adr/0001-inline-get-diff-instead-of-cruft.md mentions subprocess_utils.get_git_executable in passing — update that reference to models.get_git_executable if it appears as a code reference, otherwise leave prose unchanged.
• models.py already imports shutil for shutil.copy2, so no new top-level import is needed.

This pull request was created from Copilot chat.

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