From 26233756567beafb1113f5a2f6bee2789c81c47d Mon Sep 17 00:00:00 2001
From: Dmitry Pershin <dapper1291@gmail.com>
Date: Sat, 20 Jan 2024 16:46:50 +0500
Subject: [PATCH 1/2] snapshot sourceline bug fixed. sourceline was not being
 copied to snapshot which led to incorrect error message.

---
 pydantic_xml/element/element.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pydantic_xml/element/element.py b/pydantic_xml/element/element.py
index 4a99e30..d46113d 100644
--- a/pydantic_xml/element/element.py
+++ b/pydantic_xml/element/element.py
@@ -305,6 +305,7 @@ def create_snapshot(self) -> 'XmlElement[NativeElement]':
             attributes=dict(self._state.attrib) if self._state.attrib is not None else None,
             elements=[element.create_snapshot() for element in self._state.elements],
             nsmap=dict(self._nsmap) if self._nsmap is not None else None,
+            sourceline=self._sourceline,
         )
         element._state.next_element_idx = self._state.next_element_idx
 

From 9fce737b537c7a8f61041e8ef8a63fdd88b8ddb9 Mon Sep 17 00:00:00 2001
From: Dmitry Pershin <dapper1291@gmail.com>
Date: Sat, 20 Jan 2024 16:54:30 +0500
Subject: [PATCH 2/2] Union collection deserialization bug fixed.
 Deserialization proces gets stuck for List[Union] typed field because element
 index is not incremented if a validation error raised.

---
 pydantic_xml/element/element.py             |  9 ++++
 pydantic_xml/serializers/factories/union.py |  1 +
 tests/test_errors.py                        | 47 +++++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/pydantic_xml/element/element.py b/pydantic_xml/element/element.py
index d46113d..6e82093 100644
--- a/pydantic_xml/element/element.py
+++ b/pydantic_xml/element/element.py
@@ -116,6 +116,12 @@ def apply_snapshot(self, snapshot: 'XmlElement[Any]') -> None:
         Applies a snapshot to the current element.
         """
 
+    @abc.abstractmethod
+    def step_forward(self) -> None:
+        """
+        Increment the current element index.
+        """
+
     @abc.abstractmethod
     def to_native(self) -> Any:
         """
@@ -320,6 +326,9 @@ def apply_snapshot(self, snapshot: 'XmlElement[NativeElement]') -> None:
         self._state.elements = snapshot._state.elements
         self._state.next_element_idx = snapshot._state.next_element_idx
 
+    def step_forward(self) -> None:
+        self._state.next_element_idx += 1
+
     def is_empty(self) -> bool:
         if not self._state.text and not self._state.tail and not self._state.attrib and len(self._state.elements) == 0:
             return True
diff --git a/pydantic_xml/serializers/factories/union.py b/pydantic_xml/serializers/factories/union.py
index d1e4136..58e94e0 100644
--- a/pydantic_xml/serializers/factories/union.py
+++ b/pydantic_xml/serializers/factories/union.py
@@ -117,6 +117,7 @@ def deserialize(
                 last_error = e
 
         if last_error is not None:
+            element.step_forward()
             raise last_error
 
         return result
diff --git a/tests/test_errors.py b/tests/test_errors.py
index a72fdc3..d23dd82 100644
--- a/tests/test_errors.py
+++ b/tests/test_errors.py
@@ -170,3 +170,50 @@ class TestModel(BaseXmlModel, tag='model'):
             },
         },
     ]
+
+
+def test_models_union_errors():
+    class TestSubModel1(BaseXmlModel, tag='submodel1'):
+        data: int
+
+    class TestSubModel2(BaseXmlModel, tag='submodel2'):
+        data: float
+
+    class TestModel(BaseXmlModel, tag='model'):
+        submodel: List[Union[TestSubModel1, TestSubModel2]]
+
+    xml = '''
+        <model>
+            <submodel2>a</submodel2>
+            <submodel1>b</submodel1>
+        </model>
+    '''
+
+    with pytest.raises(pd.ValidationError) as exc:
+        TestModel.from_xml(xml)
+
+    err = exc.value
+    assert err.title == 'TestModel'
+    assert err.error_count() == 2
+    assert err.errors() == [
+        {
+            'input': 'a',
+            'loc': ('submodel', 0, 'data'),
+            'msg': f'[line {fmt_sourceline(3)}]: Input should be a valid number, unable to parse string as a number',
+            'type': 'float_parsing',
+            'ctx': {
+                'orig': 'Input should be a valid number, unable to parse string as a number',
+                'sourceline': fmt_sourceline(3),
+            },
+        },
+        {
+            'input': 'b',
+            'loc': ('submodel', 1, 'data'),
+            'msg': f'[line {fmt_sourceline(4)}]: Input should be a valid integer, unable to parse string as an integer',
+            'type': 'int_parsing',
+            'ctx': {
+                'orig': 'Input should be a valid integer, unable to parse string as an integer',
+                'sourceline': fmt_sourceline(4),
+            },
+        },
+    ]