fix(version): unshadow the resolver's fallback binding; test all branches

Completes #196 for current main:

- _resolve_version bound the name `version` twice (importlib's function, then
  the _version.py string) — runtime-correct but mypy-illegal; use distinct
  names and drop a stale type-ignore.
- tests/test_version_resolution.py covers every branch: metadata present,
  metadata missing -> setuptools_scm _version.py, nothing available ->
  "unknown" sentinel, and the module __getattr__.
- omit the setuptools_scm-GENERATED src/rustfava/_version.py from coverage:
  the new version_file config makes builds emit it locally, and a generated
  file's unexecuted branches were failing the 100% gate.

566 passed, coverage 100.00%, mypy clean.

Author: robcohen

pyproject.toml

@@ -189,6 +189,8 @@ testpaths = ["tests"]
 [tool.coverage.run]
 branch = true
 omit = [
+    # setuptools_scm-generated at build time (issue #191); not source code
+    "src/rustfava/_version.py",
     "src/rustfava/beans/types.py",
     "src/rustfava/ext/auto_commit.py",
     # Rustledger integration - new code with many error handling paths

src/rustfava/__init__.py

@@ -32,15 +32,15 @@ def _resolve_version() -> str:
     previously 500'd the help page, see issue #191).
     """
     try:
-        from importlib.metadata import version
+        from importlib.metadata import version as metadata_version
 
-        return version("rustfava")
-    except Exception:  # noqa: BLE001 - any metadata failure falls through
+        return metadata_version("rustfava")
+    except Exception:  # noqa: BLE001, S110 - any metadata failure falls through
         pass
     try:
-        from ._version import version  # type: ignore[import-not-found]
+        from ._version import version as scm_version
 
-        return version
+        return str(scm_version)
     except Exception:  # noqa: BLE001
         return "unknown"
 

tests/test_version_resolution.py

@@ -0,0 +1,62 @@
+"""Version resolution never raises, whatever the packaging situation.
+
+Regression coverage for https://github.com/rustledger/rustfava/issues/191 —
+packaged builds (PyInstaller sidecar, ``.deb``) ship the source without
+``*.dist-info`` metadata, and the help page 500'd with
+``PackageNotFoundError`` on the unguarded ``importlib.metadata.version``
+call. ``rustfava._resolve_version`` falls back to the setuptools_scm-generated
+``_version.py`` and finally to a sentinel.
+"""
+
+from __future__ import annotations
+
+import importlib.metadata
+import sys
+import types
+
+import pytest
+
+import rustfava
+
+
+@pytest.fixture
+def no_dist_metadata(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Make the ``importlib.metadata`` lookup fail like a packaged build."""
+
+    def raise_not_found(_name: str) -> str:
+        raise importlib.metadata.PackageNotFoundError
+
+    monkeypatch.setattr(importlib.metadata, "version", raise_not_found)
+
+
+def test_installed_wheel_reports_metadata_version() -> None:
+    """The normal path: dist-info metadata is present (this test env)."""
+    version = rustfava._resolve_version()
+    assert version
+    assert version != "unknown"
+
+
+@pytest.mark.usefixtures("no_dist_metadata")
+def test_falls_back_to_scm_version_file(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """No metadata, but the setuptools_scm version file is bundled."""
+    fake = types.ModuleType("rustfava._version")
+    fake.version = "1.2.3+packaged"  # type: ignore[attr-defined]
+    monkeypatch.setitem(sys.modules, "rustfava._version", fake)
+    assert rustfava._resolve_version() == "1.2.3+packaged"
+
+
+@pytest.mark.usefixtures("no_dist_metadata")
+def test_falls_back_to_sentinel_when_nothing_available(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Neither metadata nor a version file: a sentinel, never an exception."""
+    monkeypatch.setitem(sys.modules, "rustfava._version", None)
+    assert rustfava._resolve_version() == "unknown"
+
+
+def test_module_getattr_serves_version_and_rejects_others() -> None:
+    assert rustfava.__version__ == rustfava._resolve_version()
+    with pytest.raises(AttributeError):
+        _ = rustfava.no_such_attribute