Fix negative enums (#134)

Author: AdrienVannson

betterproto2/src/betterproto2/__init__.py

@@ -866,11 +866,15 @@ def _get_field_default(self, field_name: str) -> Any:
     def _postprocess_single(self, wire_type: int, meta: FieldMetadata, field_name: str, value: Any) -> Any:
         """Adjusts values after parsing."""
         if wire_type == WIRE_VARINT:
-            if meta.proto_type in (TYPE_INT32, TYPE_INT64):
+            if meta.proto_type in (TYPE_INT32, TYPE_INT64, TYPE_ENUM):
                 bits = 32 if meta.proto_type == TYPE_INT32 else 64
                 value = value & ((1 << bits) - 1)
                 signbit = 1 << (bits - 1)
                 value = int((value ^ signbit) - signbit)
+
+                if meta.proto_type == TYPE_ENUM:
+                    # Convert enum ints to python enum instances
+                    value = self._betterproto.cls_by_field[field_name](value)
             elif meta.proto_type in (TYPE_UINT32, TYPE_UINT64):
                 bits = 32 if meta.proto_type == TYPE_UINT32 else 64
                 value = value & ((1 << bits) - 1)
@@ -881,9 +885,6 @@ def _postprocess_single(self, wire_type: int, meta: FieldMetadata, field_name: s
             elif meta.proto_type == TYPE_BOOL:
                 # Booleans use a varint encoding, so convert it to true/false.
                 value = value > 0
-            elif meta.proto_type == TYPE_ENUM:
-                # Convert enum ints to python enum instances
-                value = self._betterproto.cls_by_field[field_name](value)
         elif wire_type in (WIRE_FIXED_32, WIRE_FIXED_64):
             fmt = _pack_fmt(meta.proto_type)
             value = struct.unpack(fmt, value)[0]

betterproto2/tests/inputs/enum/enum.json

@@ -4,6 +4,7 @@
     "ZERO",
     "ONE",
     "THREE",
-    "FOUR"
+    "FOUR",
+    "MINUS_ONE"
   ]
 }

betterproto2_compiler/src/betterproto2_compiler/templates/template.py.j2

@@ -24,14 +24,6 @@ class {{ enum.py_name | add_to_all }}(betterproto2.Enum):
 
     {% endfor %}
 
-    {% if output_file.settings.pydantic_dataclasses %}
-    @classmethod
-    def __get_pydantic_core_schema__(cls, _source_type, _handler):
-        from pydantic_core import core_schema
-
-        return core_schema.int_schema(ge=0)
-    {% endif %}
-
     {% if enum.has_renamed_entries %}
     @classmethod
     def betterproto_value_to_renamed_proto_names(cls) -> dict[int, str]:

betterproto2_compiler/tests/inputs/enum/enum.proto

@@ -14,6 +14,7 @@ enum Choice {
     // TWO = 2;
     FOUR = 4;
     THREE = 3;
+    MINUS_ONE = -1;
 }
 
 // A "C" like enum with the enum name prefixed onto members, these should be stripped