fix: proper native marshal for repeated enumeration fields (#180)

Fix for #179 . Repeated Enumerations now show the correct type when interacted with via python.

proto/marshal/collections/repeated.py

@@ -25,7 +25,7 @@ class Repeated(collections.abc.MutableSequence):
     modify the underlying field container directly.
     """
 
-    def __init__(self, sequence, *, marshal):
+    def __init__(self, sequence, *, marshal, proto_type=None):
         """Initialize a wrapper around a protobuf repeated field.
 
         Args:
@@ -35,6 +35,7 @@ def __init__(self, sequence, *, marshal):
         """
         self._pb = sequence
         self._marshal = marshal
+        self._proto_type = proto_type
 
     def __copy__(self):
         """Copy this object and return the copy."""
@@ -61,7 +62,7 @@ def __ne__(self, other):
         return not self == other
 
     def __repr__(self):
-        return repr(self.pb)
+        return repr([*self])
 
     def __setitem__(self, key, value):
         self.pb[key] = value
@@ -89,6 +90,11 @@ class RepeatedComposite(Repeated):
     @cached_property
     def _pb_type(self):
         """Return the protocol buffer type for this sequence."""
+        # Provide the marshal-given proto_type, if any.
+        # Used for RepeatedComposite of Enum.
+        if self._proto_type is not None:
+            return self._proto_type
+
         # There is no public-interface mechanism to determine the type
         # of what should go in the list (and the C implementation seems to
         # have no exposed mechanism at all).

proto/marshal/marshal.py

@@ -157,7 +157,10 @@ def to_python(self, proto_type, value, *, absent: bool = None):
         if value_type in compat.repeated_composite_types:
             return RepeatedComposite(value, marshal=self)
         if value_type in compat.repeated_scalar_types:
-            return Repeated(value, marshal=self)
+            if isinstance(proto_type, type):
+                return RepeatedComposite(value, marshal=self, proto_type=proto_type)
+            else:
+                return Repeated(value, marshal=self)
 
         # Same thing for maps of messages.
         if value_type in compat.map_composite_types:

tests/test_fields_repeated_composite.py

@@ -14,6 +14,7 @@
 
 from datetime import datetime
 from datetime import timezone
+from enum import Enum
 
 import pytest
 
@@ -95,6 +96,17 @@ class Foo(proto.Message):
     assert foo.timestamps[2].hour == 0
 
 
+def test_repeated_composite_enum():
+    class Foo(proto.Message):
+        class Bar(proto.Enum):
+            BAZ = 0
+
+        bars = proto.RepeatedField(Bar, number=1)
+
+    foo = Foo(bars=[Foo.Bar.BAZ])
+    assert isinstance(foo.bars[0], Enum)
+
+
 def test_repeated_composite_outer_write():
     class Foo(proto.Message):
         bar = proto.Field(proto.INT32, number=1)