Add identifier_preparer per-execution context for schema translates

Fixed bug where the "schema_translate_map" feature failed to be taken into
account for the use case of direct execution of
:class:`_schema.DefaultGenerator` objects such as sequences, which included
the case where they were "pre-executed" in order to generate primary key
values when implicit_returning was disabled.

Fixes: #5929
Change-Id: I3fed1d0af28be5ce9c9bb572524dcc8411633f60

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 7fddf2814..0c48fcba3 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -1141,6 +1141,17 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
             return "unknown"
 
     @util.memoized_property
+    def identifier_preparer(self):
+        if self.compiled:
+            return self.compiled.preparer
+        elif "schema_translate_map" in self.execution_options:
+            return self.dialect.identifier_preparer._with_schema_translate(
+                self.execution_options["schema_translate_map"]
+            )
+        else:
+            return self.dialect.identifier_preparer
+
+    @util.memoized_property
     def engine(self):
         return self.root_connection.engine
 
@@ -1197,6 +1208,14 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
         ):
             stmt = self.dialect._encoder(stmt)[0]
 
+        if "schema_translate_map" in self.execution_options:
+            schema_translate_map = self.execution_options.get(
+                "schema_translate_map", {}
+            )
+
+            rst = self.identifier_preparer._render_schema_translates
+            stmt = rst(stmt, schema_translate_map)
+
         if not parameters:
             if self.dialect.positional:
                 parameters = self.dialect.execute_sequence_format()