Refactor process_entry_pair to improve clarity in handling NextValueExpr return type

src/backend/distributed/planner/insert_select_planner.c

@@ -1699,43 +1699,32 @@ process_entry_pair(TargetEntry *insertEntry, TargetEntry *selectEntry,
 				   Form_pg_attribute attr, int targetEntryIndex,
 				   List **projectedEntries, List **nonProjectedEntries)
 {
-	Oid sourceType = exprType((Node *) selectEntry->expr);
+	Oid effectiveSourceType = exprType((Node *) selectEntry->expr);
 	Oid targetType = attr->atttypid;
 
 	/*
-	* If the select expression is a NextValueExpr, use its actual return type.
+	 * If the select expression is a NextValueExpr, use its actual return type.
-	*
+	 *
-	* NextValueExpr represents a call to the nextval() function, which is used to
+	 * NextValueExpr represents a call to the nextval() function, which is used to
-	* obtain the next value from a sequence—commonly for populating auto-increment
+	 * obtain the next value from a sequence—commonly for populating auto-increment
-	* columns. In many cases, nextval() returns an INT8 (bigint), but the actual
+	 * columns. In many cases, nextval() returns an INT8 (bigint), but the actual
-	* return type may differ depending on database configuration or custom implementations.
+	 * return type may differ depending on database configuration or custom implementations.
-	*
+	 *
-	* Since the target column might have a different type (e.g., INT4), we need to
+	 * Since the target column might have a different type (e.g., INT4), we need to
-	* obtain the real return type of nextval() to ensure that any type coercion is applied
+	 * obtain the real return type of nextval() to ensure that any type coercion is applied
-	* correctly. This is done by calling GetNextvalReturnTypeCatalog(), which looks up the
+	 * correctly. This is done by calling GetNextvalReturnTypeCatalog(), which looks up the
-	* function in the catalog and returns its return type. The effectiveCastFromType is then
+	 * function in the catalog and returns its return type. The effectiveSourceType is then
-	* set to this value, ensuring that subsequent comparisons and casts use the correct type.
+	 * set to this value, ensuring that subsequent comparisons and casts use the correct type.
-	*/
+	 */
 	if (IsA(selectEntry->expr, NextValueExpr))
 	{
-		Oid nextvalType = GetNextvalReturnTypeCatalog();
+		effectiveSourceType = GetNextvalReturnTypeCatalog();
-		if (targetType != nextvalType)
-		{
-			append_casted_entry(insertEntry, selectEntry,
-								nextvalType, targetType,
-								attr->attcollation, attr->atttypmod,
-								targetEntryIndex,
-								projectedEntries, nonProjectedEntries);
-		}
-		else
-		{
-			*projectedEntries = lappend(*projectedEntries, selectEntry);
-		}
 	}
-	else if (sourceType != targetType)
+
+	if (effectiveSourceType != targetType)
 	{
 		append_casted_entry(insertEntry, selectEntry,
-							sourceType, targetType,
+							effectiveSourceType, targetType,
 							attr->attcollation, attr->atttypmod,
 							targetEntryIndex,
 							projectedEntries, nonProjectedEntries);