Use expanding IN for all literal value IN expressions

The "expanding IN" feature, which generates IN expressions at query
execution time which are based on the particular parameters associated with
the statement execution, is now used for all IN expressions made against
lists of literal values.   This allows IN expressions to be fully cacheable
independently of the list of values being passed, and also includes support
for empty lists. For any scenario where the IN expression contains
non-literal SQL expressions, the old behavior of pre-rendering for each
position in the IN is maintained. The change also completes support for
expanding IN with tuples, where previously type-specific bind processors
weren't taking effect.

As part of this change, a more explicit separation between
"literal execute" and "post compile" bound parameters is being made;
as the "ansi bind rules" feature is rendering bound parameters
inline, as we now support "postcompile" generically, these should
be used here, however we have to render literal values at
execution time even for "expanding" parameters.  new test fixtures
etc. are added to assert everything goes to the right place.

Fixes: #4645
Change-Id: Iaa2b7bfbfaaf5b80799ee17c9b8507293cba6ed1

1 files changed, 27 insertions, 17 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 464c2a4d6..7d857d4fe 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -759,7 +759,7 @@ class ColumnElement(
     def reverse_operate(self, op, other, **kwargs):
         return op(other, self.comparator, **kwargs)
 
-    def _bind_param(self, operator, obj, type_=None):
+    def _bind_param(self, operator, obj, type_=None, expanding=False):
         return BindParameter(
             None,
             obj,
@@ -767,6 +767,7 @@ class ColumnElement(
             type_=type_,
             _compared_to_type=self.type,
             unique=True,
+            expanding=expanding,
         )
 
     @property
@@ -1281,7 +1282,6 @@ class BindParameter(roles.InElementRole, ColumnElement):
         self.required = required
         self.expanding = expanding
         self.literal_execute = literal_execute
-
         if type_ is None:
             if _compared_to_type is not None:
                 self.type = _compared_to_type.coerce_compared_value(
@@ -2282,20 +2282,29 @@ class Tuple(ClauseList, ColumnElement):
     def _select_iterable(self):
         return (self,)
 
-    def _bind_param(self, operator, obj, type_=None):
-        return Tuple(
-            *[
-                BindParameter(
-                    None,
-                    o,
-                    _compared_to_operator=operator,
-                    _compared_to_type=compared_to_type,
-                    unique=True,
-                    type_=type_,
-                )
-                for o, compared_to_type in zip(obj, self._type_tuple)
-            ]
-        ).self_group()
+    def _bind_param(self, operator, obj, type_=None, expanding=False):
+        if expanding:
+            return BindParameter(
+                None,
+                value=obj,
+                _compared_to_operator=operator,
+                unique=True,
+                expanding=True,
+            )._with_expanding_in_types(self._type_tuple)
+        else:
+            return Tuple(
+                *[
+                    BindParameter(
+                        None,
+                        o,
+                        _compared_to_operator=operator,
+                        _compared_to_type=compared_to_type,
+                        unique=True,
+                        type_=type_,
+                    )
+                    for o, compared_to_type in zip(obj, self._type_tuple)
+                ]
+            ).self_group()
 
 
 class Case(ColumnElement):
@@ -4240,7 +4249,7 @@ class ColumnClause(
         else:
             return name
 
-    def _bind_param(self, operator, obj, type_=None):
+    def _bind_param(self, operator, obj, type_=None, expanding=False):
         return BindParameter(
             self.key,
             obj,
@@ -4248,6 +4257,7 @@ class ColumnClause(
             _compared_to_type=self.type,
             type_=type_,
             unique=True,
+            expanding=expanding,
         )
 
     def _make_proxy(