0.1.3: one registrant per type; metaclass-registry 0.4

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## 0.1.3
+
+Requires `metaclass-registry>=0.4.0`, `objectstate>=3.0.1,<4` and
+`zmqruntime>=0.6.4,<0.7`.
+
+Changed:
+
+- A type has one inline-widget factory and one preview formatter.
+  `PreviewFormatterRegistry.register` and the inline-widget factory
+  registration raise `ValueError` when a different registrant is given for a
+  type that already has one, instead of replacing it. Registering the same
+  one again does nothing.
+
 ## 0.1.2
 
 Requires ObjectState 3 (`objectstate>=3.0,<4`).

pyproject.toml

@@ -25,12 +25,12 @@ keywords = ["forms", "reactive", "dataclass", "ui-bridge", "headless"]
 
 dependencies = [
     "docutils>=0.20",
-    "metaclass-registry>=0.1.5",
-    "objectstate>=3.0,<4",
+    "metaclass-registry>=0.4.0",
+    "objectstate>=3.0.1,<4",
     "psutil>=5.9",
     "python-introspect>=0.2.7,<0.3",
     "pyzmq>=22.0",
-    "zmqruntime>=0.6,<0.7",
+    "zmqruntime>=0.6.4,<0.7",
 ]
 
 [project.optional-dependencies]

requirements-ci.txt

@@ -1,2 +1,2 @@
 # Source candidates needed to validate this checkout before coordinated publication.
-# Empty: every first-party dependency is released (objectstate 3.0.0).
+# Empty: every first-party dependency is released (objectstate 3.0.1, zmqruntime 0.6.4, metaclass-registry 0.4.0).

src/formbridge/__init__.py

@@ -4,4 +4,4 @@
 nothing and loads no GUI toolkit.
 """
 
-__version__ = "0.1.2"
+__version__ = "0.1.3"

src/formbridge/forms/parameter_info_types.py

@@ -71,6 +71,12 @@ def register(
                 "Inline dataclass widgets can only be registered for dataclass types; "
                 f"got {dataclass_type!r}."
             )
+        registered = cls._factories.get(dataclass_type)
+        if registered is not None and registered is not widget_factory:
+            raise ValueError(
+                f"{dataclass_type.__qualname__} already has an inline widget factory "
+                f"({registered!r}); it cannot also use {widget_factory!r}."
+            )
         cls._factories[dataclass_type] = widget_factory
 
     @classmethod

src/formbridge/protocols/preview_formatter.py

@@ -39,6 +39,12 @@ def register(
             config_type: Config class to format
             formatter: Formatter function taking (config, field_name) -> str
         """
+        registered = cls._formatters.get(config_type)
+        if registered is not None and registered is not formatter:
+            raise ValueError(
+                f"{config_type.__qualname__} already has a preview formatter "
+                f"({registered!r}); it cannot also use {formatter!r}."
+            )
         cls._formatters[config_type] = formatter
 
     @classmethod

tests/test_preview_formatter_registry.py

@@ -57,6 +57,21 @@ class BaseConfig:
     assert PreviewFormatterRegistry.format_field(lazy_type(), "value") == "base"
 
 
+def test_preview_formatter_registration_rejects_a_second_formatter_for_one_type() -> None:
+    class OnceConfig:
+        pass
+
+    def formatter(_config: object, field_name: str) -> str:
+        return f"first:{field_name}"
+
+    PreviewFormatterRegistry.register(OnceConfig, formatter)
+    PreviewFormatterRegistry.register(OnceConfig, formatter)
+
+    with pytest.raises(ValueError, match="OnceConfig already has a preview formatter"):
+        PreviewFormatterRegistry.register(OnceConfig, lambda _config, _field_name: "second")
+    assert PreviewFormatterRegistry.format_field(OnceConfig(), "value") == "first:value"
+
+
 def test_group_heading_default_reads_the_objectstate_declaration() -> None:
     from objectstate.lazy_factory import abbreviation, get_group_abbreviation