implement final

Author: giograno

src/py_avro_schema/_alias.py

@@ -7,7 +7,7 @@
 
 import dataclasses
 from collections import defaultdict
-from typing import Annotated, Type, get_args, get_origin
+from typing import Annotated, Final, Type, get_args, get_origin
 
 FQN = str
 """Fully qualified name for a Python type"""
@@ -108,6 +108,10 @@ def get_field_aliases_and_actual_type(py_type: Type) -> tuple[list[str] | None,
     Check if a type contains an alias metadata via `Alias` or `Aliases` as metadata.
     It returns the eventual aliases and the type.
     """
+
+    if get_origin(py_type) is Final:
+        return [], get_args(py_type)[0]
+
     # py_type is not annotated. It can't have aliases
     if get_origin(py_type) is not Annotated:
         return [], py_type

tests/test_plain_class.py

@@ -10,7 +10,7 @@
 # specific language governing permissions and limitations under the License.
 
 import re
-from typing import Annotated
+from typing import Annotated, Final
 
 import pytest
 
@@ -143,3 +143,22 @@ class PyType:
 
     expected = {"fields": [{"name": "details", "type": "string"}], "name": "PyType", "type": "record"}
     assert_schema(PyType, expected)
+
+
+def test_typing_final():
+
+    class PyType:
+        var: Final[str]
+        field: Final[dict[str, int]]
+
+        def __init__(self):
+            self.var = "Hello World"
+            self.field = {"John": 123}
+
+    expected = {
+        "fields": [{"name": "var", "type": "string"}, {"name": "field", "type": {"type": "map", "values": "long"}}],
+        "name": "PyType",
+        "type": "record",
+    }
+
+    assert_schema(PyType, expected)