Improving error handling

Promoting case-sensitivity issue from assertion error to DataTypeNameCollisionError

pydsdl/_data_type_builder.py

@@ -245,14 +245,23 @@ def resolve_versioned_data_type(self, name: str, version: _serializable.Version)
                     path=found[1].file_path,
                 )
             raise DataTypeCollisionError("Conflicting definitions: %r" % found)
+        elif found[0].full_name != full_name and found[0].full_name.lower() == full_name.lower():
+             # pragma: no cover
+            # This only happens if the file system is case-sensitive.
+            raise DataTypeNameCollisionError(
+                "Full name of required definition %s differs from %s only by letter case, "
+                "which is not permitted" % (full_name, found[0].full_name),
+                path=found[0].file_path
+            )
 
         target_definition = found[0]
-        for visitor in self._definition_visitors:
-            visitor.on_definition(self._definition, target_definition)
 
         assert isinstance(target_definition, ReadableDSDLFile)
-        assert target_definition.full_name == full_name
         assert target_definition.version == version
+
+        for visitor in self._definition_visitors:
+            visitor.on_definition(self._definition, target_definition)
+
         # Recursion is cool.
         dt = target_definition.read(
             lookup_definitions=self._lookup_definitions,

pydsdl/_namespace.py

@@ -819,6 +819,8 @@ def _unittest_ensure_no_namespace_name_collisions_or_nested_root_namespaces() ->
 def _unittest_issue_104(temp_dsdl_factory) -> None:  # type: ignore
     """demonstrate that removing _ensure_no_collisions is okay"""
 
+    from pytest import raises
+
     thing_1_0 = Path("a/b/thing.1.0.dsdl")
     thing_type_1_0 = Path("a/b/thing/thingtype.1.0.dsdl")
 
@@ -830,3 +832,12 @@ def _unittest_issue_104(temp_dsdl_factory) -> None:  # type: ignore
 
     assert len(direct) == 1
     assert len(transitive) == 1
+
+    thing_1_1 = Path("a/b/thing.1.1.dsdl")
+
+    thing_file2 = temp_dsdl_factory.new_file(thing_1_1, "@sealed\na.b.thing.Thingtype.1.0 thing\n")
+
+    from ._data_type_builder import DataTypeNameCollisionError
+
+    with raises(DataTypeNameCollisionError):
+        read_files(thing_file2, file_at_root.parent, file_at_root.parent)