Address review comments

src/slotscheck/discovery.py

@@ -7,7 +7,7 @@
 from functools import partial, reduce
 from importlib.util import find_spec
 from inspect import isclass
-from itertools import chain, takewhile
+from itertools import chain
 from pathlib import Path
 from textwrap import indent
 from types import ModuleType
@@ -300,19 +300,32 @@ def _is_package(p: AbsPath) -> bool:
     return p.is_dir() and (p / _INIT_PY).is_file()
 
 
-def find_modules(
-    p: AbsPath, python_path: Optional[FrozenSet[AbsPath]] = None
+def _module_parents(
+    p: AbsPath, sys_path: FrozenSet[AbsPath]
+) -> Iterable[AbsPath]:
+    yield p
+    for pp in p.parents:
+        if pp in sys_path:
+            return
+        yield pp
+    raise ValueError(f"File {p} is outside of PYTHONPATH ({sys.path})")
+
+
+def _find_modules(
+    p: AbsPath, sys_path: FrozenSet[AbsPath]
 ) -> Iterable[ModuleLocated]:
-    "Recursively find modules at given path. Nonexistent Path is ignored"
-    if python_path is None:
-        python_path = frozenset(map(Path, sys.path))
     if p.name == _INIT_PY:
-        yield from find_modules(p.parent, python_path)
+        yield from _find_modules(p.parent, sys_path)
     elif _is_module(p):
-        parents = [p, *takewhile(lambda p: p not in python_path, p.parents)]
+        parents = list(_module_parents(p, sys_path))
         yield ModuleLocated(
             ".".join(p.stem for p in reversed(parents)),
             (p / _INIT_PY if _is_package(p) else p),
         )
     elif p.is_dir():
-        yield from flatten(find_modules(sp, python_path) for sp in p.iterdir())
+        yield from flatten(_find_modules(cp, sys_path) for cp in p.iterdir())
+
+
+def find_modules(p: AbsPath) -> Iterable[ModuleLocated]:
+    "Recursively find modules at given path. Nonexistent Path is ignored"
+    return _find_modules(p, frozenset(map(Path, sys.path)))

tests/src/test_cli.py

@@ -157,6 +157,16 @@ def test_multiple_modules(runner: CliRunner):
     assert result.output == "All OK!\nScanned 11 module(s), 70 class(es).\n"
 
 
+def test_implicitly_namespaced_path(runner: CliRunner):
+    result = runner.invoke(
+        cli,
+        [str(EXAMPLES_DIR / "implicitly_namespaced")],
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0
+    assert result.output == "All OK!\nScanned 7 module(s), 1 class(es).\n"
+
+
 def test_multiple_paths(runner: CliRunner):
     result = runner.invoke(
         cli,

tests/src/test_discovery.py

@@ -418,6 +418,12 @@ def test_given_init_py(self):
             ModuleLocated("files.subdir.some_module.sub", location)
         ]
 
+    def test_given_file_not_in_sys_path(self, tmp_path):
+        location = tmp_path / "foo.py"
+        location.touch()
+        with pytest.raises(ValueError, match="is outside of PYTHONPATH"):
+            list(find_modules(location))
+
 
 class TestConsolidate:
     def test_empty(self):