fix: intersect OneOf and Equal choices in field2choices

src/apispec/ext/marshmallow/field_converter.py

@@ -242,21 +242,14 @@ def field2choices(
         """
         attributes = {}
 
-        comparable = [
-            validator.comparable
-            for validator in field.validators
-            if hasattr(validator, "comparable")
-        ]
-        if comparable:
-            attributes["enum"] = comparable
-        else:
-            choices = [
-                OrderedSet(validator.choices)
-                for validator in field.validators
-                if hasattr(validator, "choices")
-            ]
-            if choices:
-                attributes["enum"] = list(functools.reduce(operator.and_, choices))
+        choices = []
+        for validator in field.validators:
+            if hasattr(validator, "choices"):
+                choices.append(OrderedSet(validator.choices))
+            elif hasattr(validator, "comparable"):
+                choices.append(OrderedSet([validator.comparable]))
+        if choices:
+            attributes["enum"] = list(functools.reduce(operator.and_, choices))
 
         if field.allow_none:
             enum = attributes.get("enum")

tests/test_ext_marshmallow_field.py

@@ -198,7 +198,62 @@ def test_field_with_choices_multiple(spec_fixture):
         ]
     )
     res = spec_fixture.openapi.field2property(field)
-    assert set(res["enum"]) == {"brian", "john"}
+    assert res["enum"] == ["brian", "john"]
+
+
+def test_field_with_choices_multiple_non_intersecting(spec_fixture):
+    field = fields.Str(
+        validate=[
+            validate.OneOf(["freddie", "brian"]),
+            validate.OneOf(["john", "roger"]),
+        ]
+    )
+    res = spec_fixture.openapi.field2property(field)
+    assert res["enum"] == []
+
+
+def test_field_with_choices_and_equal(spec_fixture):
+    field = fields.Str(
+        validate=[
+            validate.OneOf(["freddie", "brian", "john"]),
+            validate.Equal("brian"),
+        ]
+    )
+    res = spec_fixture.openapi.field2property(field)
+    assert res["enum"] == ["brian"]
+
+
+def test_field_with_choices_and_equal_non_intersecting(spec_fixture):
+    field = fields.Str(
+        validate=[
+            validate.OneOf(["freddie", "brian"]),
+            validate.Equal("john"),
+        ]
+    )
+    res = spec_fixture.openapi.field2property(field)
+    assert res["enum"] == []
+
+
+def test_field_with_multiple_equal_matching(spec_fixture):
+    field = fields.Str(
+        validate=[
+            validate.Equal("brian"),
+            validate.Equal("brian"),
+        ]
+    )
+    res = spec_fixture.openapi.field2property(field)
+    assert res["enum"] == ["brian"]
+
+
+def test_field_with_multiple_equal_conflicting(spec_fixture):
+    field = fields.Str(
+        validate=[
+            validate.Equal("freddie"),
+            validate.Equal("brian"),
+        ]
+    )
+    res = spec_fixture.openapi.field2property(field)
+    assert res["enum"] == []
 
 
 def test_field_with_additional_metadata(spec_fixture):