0.6.2: one codec per file extension; metaclass-registry 0.4

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "polystore"
-version = "0.6.1"
+version = "0.6.2"
 description = "Framework-agnostic multi-backend storage abstraction for ML and scientific computing"
 readme = "README.md"
 requires-python = ">=3.11"
@@ -40,12 +40,12 @@ dependencies = [
     "arraybridge>=0.3.0",
     "numpy>=1.26.0",
     "portalocker>=2.8.0",  # Cross-platform file locking
-    "metaclass-registry>=0.1.5",
+    "metaclass-registry>=0.4.0",
     "imageio>=2.37.0",
     "zarr>=3.0.10",  # Reads Zarr 2 and 3 stores; output format is backend-owned
     "numcodecs>=0.14.0",
     "ome-zarr>=0.12.2",   # Required for OME-ZARR HCS compliance
-    "zmqruntime>=0.6,<0.7",
+    "zmqruntime>=0.6.4,<0.7",
     "platformdirs>=4.0.0",
 ]
 

src/polystore/disk.py

@@ -34,6 +34,12 @@ def __init__(self):
 
     def register(self, ext: str, writer: Callable, reader: Callable):
         ext = ext.lower()
+        if ext in self._writers and (
+            self._writers[ext] is not writer or self._readers[ext] is not reader
+        ):
+            raise ValueError(
+                f"File format {ext!r} already has a writer and a reader registered."
+            )
         self._writers[ext] = writer
         self._readers[ext] = reader
 

tests/test_disk_coverage.py

@@ -553,8 +553,8 @@ def test_save_dispatches_registered_compound_extension(self, tmp_path):
         def writer(path, data, **kwargs):
             written.append((path, data, kwargs))
 
-        self.backend.format_registry.register(".roi.zip", writer, lambda path: path)
-        output_path = tmp_path / "objects.roi.zip"
+        self.backend.format_registry.register(".witness.zip", writer, lambda path: path)
+        output_path = tmp_path / "objects.witness.zip"
         payload = {"object_id": 1}
 
         self.backend.save(payload, output_path, source="regression")

tests/test_disk_more.py

@@ -162,3 +162,20 @@ def test_list_files_breadth_first_order(tmp_path: Path):
     assert str_files.index(
         next(s for s in str_files if s.endswith("rootfile.txt"))
     ) < str_files.index(next(s for s in str_files if s.endswith("deep.txt")))
+
+
+def test_file_format_registry_rejects_a_second_codec_for_one_extension():
+    registry = FileFormatRegistry()
+
+    def writer(path, data):
+        path.write_text(str(data))
+
+    def reader(path):
+        return path.read_text()
+
+    registry.register(".foo", writer, reader)
+    registry.register(".FOO", writer, reader)  # the same codec again is not a conflict
+
+    with pytest.raises(ValueError, match="'.foo' already has a writer and a reader"):
+        registry.register(".foo", lambda path, data: None, reader)
+    assert registry.get_writer(".foo") is writer