Merge "Fix coercion issue for tuple bindparams" into main

3 files changed, 30 insertions, 4 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 4c2c7de3c..e51b755dd 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -1976,8 +1976,11 @@ class BindParameter(roles.InElementRole, KeyedColumnElement[_T]):
             self._is_crud = True
 
         if type_ is None:
-            if expanding and value:
-                check_value = value[0]
+            if expanding:
+                if value:
+                    check_value = value[0]
+                else:
+                    check_value = type_api._NO_VALUE_IN_LIST
             else:
                 check_value = value
             if _compared_to_type is not None:
@@ -3166,7 +3169,8 @@ class Tuple(ClauseList, ColumnElement[typing_Tuple[Any, ...]]):
                 _compared_to_operator=operator,
                 unique=True,
                 expanding=True,
-                type_=self.type,
+                type_=type_,
+                _compared_to_type=self.type,
             )
         else:
             return Tuple(
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index b2dcc9b8a..3c6cb0cb5 100644
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -3157,6 +3157,20 @@ class TupleType(TypeEngine[Tuple[Any, ...]]):
             for item_type in types
         ]
 
+    def coerce_compared_value(
+        self, op: Optional[OperatorType], value: Any
+    ) -> TypeEngine[Any]:
+
+        if value is type_api._NO_VALUE_IN_LIST:
+            return super().coerce_compared_value(op, value)
+        else:
+            return TupleType(
+                *[
+                    typ.coerce_compared_value(op, elem)
+                    for typ, elem in zip(self.types, value)
+                ]
+            )
+
     def _resolve_values_to_types(self, value: Any) -> TupleType:
         if self._fully_typed:
             return self
diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index af7ed21c4..7167430f1 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -11,6 +11,7 @@
 
 from __future__ import annotations
 
+from enum import Enum
 from types import ModuleType
 import typing
 from typing import Any
@@ -68,7 +69,14 @@ _CT = TypeVar("_CT", bound=Any)
 
 _MatchedOnType = Union["GenericProtocol[Any]", NewType, Type[Any]]
 
-# replace with pep-673 when applicable
+
+class _NoValueInList(Enum):
+    NO_VALUE_IN_LIST = 0
+    """indicates we are trying to determine the type of an expression
+    against an empty list."""
+
+
+_NO_VALUE_IN_LIST = _NoValueInList.NO_VALUE_IN_LIST
 
 
 class _LiteralProcessorType(Protocol[_T_co]):