Ensure LocalStore.prefix is a pathlib.Path (#219)

* Ensure `LocalStore.prefix` is a `pathlib.Path`

* bump to 0.4.0-beta.3

obstore/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "obstore"
-version = "0.4.0-beta.2"
+version = "0.4.0-beta.3"
 authors = { workspace = true }
 edition = { workspace = true }
 description = "The simplest, highest-throughput interface to Amazon S3, Google Cloud Storage, Azure Blob Storage, and S3-compliant APIs like Cloudflare R2."

obstore/python/obstore/store/__init__.pyi

@@ -153,6 +153,9 @@ class LocalStore:
 
     def __getnewargs_ex__(self): ...
     def __repr__(self) -> str: ...
+    @property
+    def prefix(self) -> Path | None:
+        """Get the prefix applied to all operations in this store, if any."""
 
 class MemoryStore:
     """A fully in-memory implementation of ObjectStore.

pyo3-object_store/src/local.rs

@@ -113,7 +113,19 @@ impl PyLocalStore {
     }
 
     #[getter]
-    fn prefix(&self) -> Option<&std::path::PathBuf> {
-        self.config.prefix.as_ref()
+    fn prefix(&self, py: Python) -> PyResult<PyObject> {
+        // Note: returning a std::path::Path or std::path::PathBuf converts back to a Python _str_
+        // not a Python _pathlib.Path_.
+        // So we manually convert to a pathlib.Path
+        if let Some(prefix) = &self.config.prefix {
+            let pathlib_mod = py.import(intern!(py, "pathlib"))?;
+            let path_object = pathlib_mod.call_method1(
+                intern!(py, "Path"),
+                PyTuple::new(py, vec![prefix.into_pyobject(py)?])?,
+            )?;
+            path_object.into_py_any(py)
+        } else {
+            Ok(py.None())
+        }
     }
 }

tests/store/test_local.py

@@ -54,3 +54,12 @@ def test_create_prefix():
     # Assert that mkdir=True works even when the dir already exists
     LocalStore(tmpdir, mkdir=True)
     assert tmpdir.exists()
+
+
+def test_prefix_property():
+    tmpdir = Path(tempfile.gettempdir())
+    store = LocalStore(tmpdir)
+    assert store.prefix == tmpdir
+    assert isinstance(store.prefix, Path)
+    # Can pass it back to the store init
+    LocalStore(store.prefix)