Fix: to_dict returns wrong enum fields when numbering is not consecutive

src/betterproto/__init__.py

@@ -4,6 +4,7 @@
 import json
 import struct
 import sys
+import warnings
 from abc import ABC
 from base64 import b64decode, b64encode
 from datetime import datetime, timedelta, timezone
@@ -21,6 +22,8 @@
     get_type_hints,
 )
 
+import typing
+
 from ._types import T
 from .casing import camel_case, safe_snake_case, snake_case
 from .grpc.grpclib_client import ServiceStub
@@ -251,7 +254,7 @@ def map_field(
     )
 
 
-class Enum(int, enum.Enum):
+class Enum(enum.IntEnum):
     """Protocol buffers enumeration base class. Acts like `enum.IntEnum`."""
 
     @classmethod
@@ -635,9 +638,13 @@ def __bytes__(self) -> bytes:
 
     @classmethod
     def _type_hint(cls, field_name: str) -> Type:
+        return cls._type_hints()[field_name]
+
+    @classmethod
+    def _type_hints(cls) -> Dict[str, Type]:
         module = inspect.getmodule(cls)
         type_hints = get_type_hints(cls, vars(module))
-        return type_hints[field_name]
+        return type_hints
 
     @classmethod
     def _cls_for(cls, field: dataclasses.Field, index: int = 0) -> Type:
@@ -789,55 +796,67 @@ def to_dict(
         `False`.
         """
         output: Dict[str, Any] = {}
+        field_types = self._type_hints()
         for field_name, meta in self._betterproto.meta_by_field_name.items():
-            v = getattr(self, field_name)
+            field_type = field_types[field_name]
+            field_is_repeated = type(field_type) is type(typing.List)
+            value = getattr(self, field_name)
             cased_name = casing(field_name).rstrip("_")  # type: ignore
-            if meta.proto_type == "message":
-                if isinstance(v, datetime):
-                    if v != DATETIME_ZERO or include_default_values:
-                        output[cased_name] = _Timestamp.timestamp_to_json(v)
-                elif isinstance(v, timedelta):
-                    if v != timedelta(0) or include_default_values:
-                        output[cased_name] = _Duration.delta_to_json(v)
+            if meta.proto_type == TYPE_MESSAGE:
+                if isinstance(value, datetime):
+                    if value != DATETIME_ZERO or include_default_values:
+                        output[cased_name] = _Timestamp.timestamp_to_json(value)
+                elif isinstance(value, timedelta):
+                    if value != timedelta(0) or include_default_values:
+                        output[cased_name] = _Duration.delta_to_json(value)
                 elif meta.wraps:
-                    if v is not None or include_default_values:
-                        output[cased_name] = v
-                elif isinstance(v, list):
+                    if value is not None or include_default_values:
+                        output[cased_name] = value
+                elif field_is_repeated:
                     # Convert each item.
-                    v = [i.to_dict(casing, include_default_values) for i in v]
-                    if v or include_default_values:
-                        output[cased_name] = v
+                    value = [i.to_dict(casing, include_default_values) for i in value]
+                    if value or include_default_values:
+                        output[cased_name] = value
                 else:
-                    if v._serialized_on_wire or include_default_values:
-                        output[cased_name] = v.to_dict(casing, include_default_values)
-            elif meta.proto_type == "map":
-                for k in v:
-                    if hasattr(v[k], "to_dict"):
-                        v[k] = v[k].to_dict(casing, include_default_values)
-
-                if v or include_default_values:
-                    output[cased_name] = v
-            elif v != self._get_field_default(field_name) or include_default_values:
+                    if value._serialized_on_wire or include_default_values:
+                        output[cased_name] = value.to_dict(
+                            casing, include_default_values
+                        )
+            elif meta.proto_type == TYPE_MAP:
+                for k in value:
+                    if hasattr(value[k], "to_dict"):
+                        value[k] = value[k].to_dict(casing, include_default_values)
+
+                if value or include_default_values:
+                    output[cased_name] = value
+            elif value != self._get_field_default(field_name) or include_default_values:
                 if meta.proto_type in INT_64_TYPES:
-                    if isinstance(v, list):
-                        output[cased_name] = [str(n) for n in v]
+                    if field_is_repeated:
+                        output[cased_name] = [str(n) for n in value]
                     else:
-                        output[cased_name] = str(v)
+                        output[cased_name] = str(value)
                 elif meta.proto_type == TYPE_BYTES:
-                    if isinstance(v, list):
-                        output[cased_name] = [b64encode(b).decode("utf8") for b in v]
+                    if field_is_repeated:
+                        output[cased_name] = [
+                            b64encode(b).decode("utf8") for b in value
+                        ]
                     else:
-                        output[cased_name] = b64encode(v).decode("utf8")
+                        output[cased_name] = b64encode(value).decode("utf8")
                 elif meta.proto_type == TYPE_ENUM:
-                    enum_values = list(
-                        self._betterproto.cls_by_field[field_name]
-                    )  # type: ignore
-                    if isinstance(v, list):
-                        output[cased_name] = [enum_values[e].name for e in v]
+                    if field_is_repeated:
+                        enum_class: Type[Enum] = field_type.__args__[0]
+                        if isinstance(value, typing.Iterable) and not isinstance(
+                            value, str
+                        ):
+                            output[cased_name] = [enum_class(el).name for el in value]
+                        else:
+                            # transparently upgrade single value to repeated
+                            output[cased_name] = [enum_class(value).name]
                     else:
-                        output[cased_name] = enum_values[v].name
+                        enum_class: Type[Enum] = field_type  # noqa
+                        output[cased_name] = enum_class(value).name
                 else:
-                    output[cased_name] = v
+                    output[cased_name] = value
         return output
 
     def from_dict(self: T, value: dict) -> T:

tests/inputs/config.py

@@ -5,7 +5,7 @@
     "namespace_keywords",  # 70
     "namespace_builtin_types",  # 53
     "googletypes_struct",  # 9
-    "googletypes_value",  # 9,
+    "googletypes_value",  # 9
     "import_capitalized_package",
     "example",  # This is the example in the readme. Not a test.
 }

tests/inputs/enum/enum.json

@@ -0,0 +1,9 @@
+{
+  "choice": "FOUR",
+  "choices": [
+    "ZERO",
+    "ONE",
+    "THREE",
+    "FOUR"
+  ]
+}

tests/inputs/enum/enum.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+// Tests that enums are correctly serialized and that it correctly handles skipped and out-of-order enum values
+message Test {
+  Choice choice = 1;
+  repeated Choice choices = 2;
+}
+
+enum Choice {
+  ZERO = 0;
+  ONE = 1;
+  // TWO = 2;
+  FOUR = 4;
+  THREE = 3;
+}

tests/inputs/enum/test_enum.py

@@ -0,0 +1,84 @@
+from tests.output_betterproto.enum import (
+    Test,
+    Choice,
+)
+
+
+def test_enum_set_and_get():
+    assert Test(choice=Choice.ZERO).choice == Choice.ZERO
+    assert Test(choice=Choice.ONE).choice == Choice.ONE
+    assert Test(choice=Choice.THREE).choice == Choice.THREE
+    assert Test(choice=Choice.FOUR).choice == Choice.FOUR
+
+
+def test_enum_set_with_int():
+    assert Test(choice=0).choice == Choice.ZERO
+    assert Test(choice=1).choice == Choice.ONE
+    assert Test(choice=3).choice == Choice.THREE
+    assert Test(choice=4).choice == Choice.FOUR
+
+
+def test_enum_is_comparable_with_int():
+    assert Test(choice=Choice.ZERO).choice == 0
+    assert Test(choice=Choice.ONE).choice == 1
+    assert Test(choice=Choice.THREE).choice == 3
+    assert Test(choice=Choice.FOUR).choice == 4
+
+
+def test_enum_to_dict():
+    assert (
+        "choice" not in Test(choice=Choice.ZERO).to_dict()
+    ), "Default enum value is not serialized"
+    assert (
+        Test(choice=Choice.ZERO).to_dict(include_default_values=True)["choice"]
+        == "ZERO"
+    )
+    assert Test(choice=Choice.ONE).to_dict()["choice"] == "ONE"
+    assert Test(choice=Choice.THREE).to_dict()["choice"] == "THREE"
+    assert Test(choice=Choice.FOUR).to_dict()["choice"] == "FOUR"
+
+
+def test_repeated_enum_is_comparable_with_int():
+    assert Test(choices=[Choice.ZERO]).choices == [0]
+    assert Test(choices=[Choice.ONE]).choices == [1]
+    assert Test(choices=[Choice.THREE]).choices == [3]
+    assert Test(choices=[Choice.FOUR]).choices == [4]
+
+
+def test_repeated_enum_set_and_get():
+    assert Test(choices=[Choice.ZERO]).choices == [Choice.ZERO]
+    assert Test(choices=[Choice.ONE]).choices == [Choice.ONE]
+    assert Test(choices=[Choice.THREE]).choices == [Choice.THREE]
+    assert Test(choices=[Choice.FOUR]).choices == [Choice.FOUR]
+
+
+def test_repeated_enum_to_dict():
+    assert Test(choices=[Choice.ZERO]).to_dict()["choices"] == ["ZERO"]
+    assert Test(choices=[Choice.ONE]).to_dict()["choices"] == ["ONE"]
+    assert Test(choices=[Choice.THREE]).to_dict()["choices"] == ["THREE"]
+    assert Test(choices=[Choice.FOUR]).to_dict()["choices"] == ["FOUR"]
+
+    all_enums_dict = Test(
+        choices=[Choice.ZERO, Choice.ONE, Choice.THREE, Choice.FOUR]
+    ).to_dict()
+    assert (all_enums_dict["choices"]) == ["ZERO", "ONE", "THREE", "FOUR"]
+
+
+def test_repeated_enum_with_single_value_to_dict():
+    assert Test(choices=Choice.ONE).to_dict()["choices"] == ["ONE"]
+    assert Test(choices=1).to_dict()["choices"] == ["ONE"]
+
+
+def test_repeated_enum_with_non_list_iterables_to_dict():
+    assert Test(choices=(1, 3)).to_dict()["choices"] == ["ONE", "THREE"]
+    assert Test(choices=(1, 3)).to_dict()["choices"] == ["ONE", "THREE"]
+    assert Test(choices=(Choice.ONE, Choice.THREE)).to_dict()["choices"] == [
+        "ONE",
+        "THREE",
+    ]
+
+    def enum_generator():
+        yield Choice.ONE
+        yield Choice.THREE
+
+    assert Test(choices=enum_generator()).to_dict()["choices"] == ["ONE", "THREE"]