collect errors at the end :)

Author: sydney-runkle

src/serializers/type_serializers/union.rs

@@ -78,13 +78,14 @@ impl TypeSerializer for UnionSerializer {
         // try the serializers in left to right order with error_on fallback=true
         let mut new_extra = extra.clone();
         new_extra.check = SerCheck::Strict;
+        let mut errors: Vec<PyErr> = Vec::new();
 
         for comb_serializer in &self.choices {
             match comb_serializer.to_python(value, include, exclude, &new_extra) {
                 Ok(v) => return Ok(v),
                 Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(value.py()) {
                     true => (),
-                    false => extra.warnings.custom_warning(err.to_string()),
+                    false => errors.push(err),
                 },
             }
         }
@@ -95,25 +96,31 @@ impl TypeSerializer for UnionSerializer {
                     Ok(v) => return Ok(v),
                     Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(value.py()) {
                         true => (),
-                        false => extra.warnings.custom_warning(err.to_string()),
+                        false => errors.push(err),
                     },
                 }
             }
         }
 
+        for err in &errors {
+            extra.warnings.custom_warning(err.to_string());
+        }
+
         extra.warnings.on_fallback_py(self.get_name(), value, extra)?;
         infer_to_python(value, include, exclude, extra)
     }
 
     fn json_key<'a>(&self, key: &'a Bound<'_, PyAny>, extra: &Extra) -> PyResult<Cow<'a, str>> {
         let mut new_extra = extra.clone();
         new_extra.check = SerCheck::Strict;
+        let mut errors: Vec<PyErr> = Vec::new();
+
         for comb_serializer in &self.choices {
             match comb_serializer.json_key(key, &new_extra) {
                 Ok(v) => return Ok(v),
                 Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(key.py()) {
                     true => (),
-                    false => extra.warnings.custom_warning(err.to_string()),
+                    false => errors.push(err),
                 },
             }
         }
@@ -124,12 +131,16 @@ impl TypeSerializer for UnionSerializer {
                     Ok(v) => return Ok(v),
                     Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(key.py()) {
                         true => (),
-                        false => extra.warnings.custom_warning(err.to_string()),
+                        false => errors.push(err),
                     },
                 }
             }
         }
 
+        for err in &errors {
+            extra.warnings.custom_warning(err.to_string());
+        }
+
         extra.warnings.on_fallback_py(self.get_name(), key, extra)?;
         infer_json_key(key, extra)
     }
@@ -145,13 +156,14 @@ impl TypeSerializer for UnionSerializer {
         let py = value.py();
         let mut new_extra = extra.clone();
         new_extra.check = SerCheck::Strict;
+        let mut errors: Vec<PyErr> = Vec::new();
 
         for comb_serializer in &self.choices {
             match comb_serializer.to_python(value, include, exclude, &new_extra) {
                 Ok(v) => return infer_serialize(v.bind(py), serializer, None, None, extra),
                 Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(value.py()) {
                     true => (),
-                    false => extra.warnings.custom_warning(err.to_string()),
+                    false => errors.push(err),
                 },
             }
         }
@@ -162,12 +174,16 @@ impl TypeSerializer for UnionSerializer {
                     Ok(v) => return infer_serialize(v.bind(py), serializer, None, None, extra),
                     Err(err) => match err.is_instance_of::<PydanticSerializationUnexpectedValue>(value.py()) {
                         true => (),
-                        false => extra.warnings.custom_warning(err.to_string()),
+                        false => errors.push(err),
                     },
                 }
             }
         }
 
+        for err in &errors {
+            extra.warnings.custom_warning(err.to_string());
+        }
+
         extra.warnings.on_fallback_ser::<S>(self.get_name(), value, extra)?;
         infer_serialize(value, serializer, include, exclude, extra)
     }

tests/serializers/test_union.py

@@ -647,5 +647,6 @@ def test_custom_serializer() -> None:
             ]
         )
     )
+    print(s)
     assert s.to_python([{'id': 1}, {'id': 2}]) == [1, 2]
     assert s.to_python({'id': 1}) == 1