Fix behavior of AND CHAIN outside of explicit transaction blocks

When using COMMIT AND CHAIN or ROLLBACK AND CHAIN not in an explicit
transaction block, the previous implementation would leave a
transaction block active in the ROLLBACK case but not the COMMIT case.
To fix for now, error out when using these commands not in an explicit
transaction block.  This restriction could be lifted if a sensible
definition and implementation is found.

Bug: #15977
Author: fn ln <emuser20140816@gmail.com>
Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>

src/test/regress/expected/transactions.out

@@ -839,6 +839,11 @@ SHOW transaction_deferrable;
 (1 row)
 
 ROLLBACK;
+-- not allowed outside a transaction block
+COMMIT AND CHAIN;  -- error
+ERROR:  COMMIT AND CHAIN can only be used in transaction blocks
+ROLLBACK AND CHAIN;  -- error
+ERROR:  ROLLBACK AND CHAIN can only be used in transaction blocks
 SELECT * FROM abc ORDER BY 1;
  a 
 ---
@@ -934,6 +939,79 @@ SELECT 2\; RELEASE SAVEPOINT sp\; SELECT 3;
 ERROR:  RELEASE SAVEPOINT can only be used in transaction blocks
 -- but this is OK, because the BEGIN converts it to a regular xact
 SELECT 1\; BEGIN\; SAVEPOINT sp\; ROLLBACK TO SAVEPOINT sp\; COMMIT;
+-- Tests for AND CHAIN in implicit transaction blocks
+SET TRANSACTION READ WRITE\; COMMIT AND CHAIN;  -- error
+ERROR:  COMMIT AND CHAIN can only be used in transaction blocks
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SET TRANSACTION READ WRITE\; ROLLBACK AND CHAIN;  -- error
+ERROR:  ROLLBACK AND CHAIN can only be used in transaction blocks
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+CREATE TABLE abc (a int);
+-- COMMIT/ROLLBACK + COMMIT/ROLLBACK AND CHAIN
+INSERT INTO abc VALUES (7)\; COMMIT\; INSERT INTO abc VALUES (8)\; COMMIT AND CHAIN;  -- 7 commit, 8 error
+WARNING:  there is no transaction in progress
+ERROR:  COMMIT AND CHAIN can only be used in transaction blocks
+INSERT INTO abc VALUES (9)\; ROLLBACK\; INSERT INTO abc VALUES (10)\; ROLLBACK AND CHAIN;  -- 9 rollback, 10 error
+WARNING:  there is no transaction in progress
+ERROR:  ROLLBACK AND CHAIN can only be used in transaction blocks
+-- COMMIT/ROLLBACK AND CHAIN + COMMIT/ROLLBACK
+INSERT INTO abc VALUES (11)\; COMMIT AND CHAIN\; INSERT INTO abc VALUES (12)\; COMMIT;  -- 11 error, 12 not reached
+ERROR:  COMMIT AND CHAIN can only be used in transaction blocks
+INSERT INTO abc VALUES (13)\; ROLLBACK AND CHAIN\; INSERT INTO abc VALUES (14)\; ROLLBACK;  -- 13 error, 14 not reached
+ERROR:  ROLLBACK AND CHAIN can only be used in transaction blocks
+-- START TRANSACTION + COMMIT/ROLLBACK AND CHAIN
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (15)\; COMMIT AND CHAIN;  -- 15 ok
+SHOW transaction_isolation;  -- transaction is active at this point
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+COMMIT;
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (16)\; ROLLBACK AND CHAIN;  -- 16 ok
+SHOW transaction_isolation;  -- transaction is active at this point
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+ROLLBACK;
+-- START TRANSACTION + COMMIT/ROLLBACK + COMMIT/ROLLBACK AND CHAIN
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (17)\; COMMIT\; INSERT INTO abc VALUES (18)\; COMMIT AND CHAIN;  -- 17 commit, 18 error
+ERROR:  COMMIT AND CHAIN can only be used in transaction blocks
+SHOW transaction_isolation;  -- out of transaction block
+ transaction_isolation 
+-----------------------
+ read committed
+(1 row)
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (19)\; ROLLBACK\; INSERT INTO abc VALUES (20)\; ROLLBACK AND CHAIN;  -- 19 rollback, 20 error
+ERROR:  ROLLBACK AND CHAIN can only be used in transaction blocks
+SHOW transaction_isolation;  -- out of transaction block
+ transaction_isolation 
+-----------------------
+ read committed
+(1 row)
+
+SELECT * FROM abc ORDER BY 1;
+ a  
+----
+  7
+ 15
+ 17
+(3 rows)
+
+DROP TABLE abc;
 -- Test for successful cleanup of an aborted transaction at session exit.
 -- THIS MUST BE THE LAST TEST IN THIS FILE.
 begin;

src/test/regress/sql/transactions.sql

@@ -475,6 +475,10 @@ SHOW transaction_read_only;
 SHOW transaction_deferrable;
 ROLLBACK;
 
+-- not allowed outside a transaction block
+COMMIT AND CHAIN;  -- error
+ROLLBACK AND CHAIN;  -- error
+
 SELECT * FROM abc ORDER BY 1;
 
 RESET default_transaction_read_only;
@@ -536,6 +540,45 @@ SELECT 2\; RELEASE SAVEPOINT sp\; SELECT 3;
 SELECT 1\; BEGIN\; SAVEPOINT sp\; ROLLBACK TO SAVEPOINT sp\; COMMIT;
 
 
+-- Tests for AND CHAIN in implicit transaction blocks
+
+SET TRANSACTION READ WRITE\; COMMIT AND CHAIN;  -- error
+SHOW transaction_read_only;
+
+SET TRANSACTION READ WRITE\; ROLLBACK AND CHAIN;  -- error
+SHOW transaction_read_only;
+
+CREATE TABLE abc (a int);
+
+-- COMMIT/ROLLBACK + COMMIT/ROLLBACK AND CHAIN
+INSERT INTO abc VALUES (7)\; COMMIT\; INSERT INTO abc VALUES (8)\; COMMIT AND CHAIN;  -- 7 commit, 8 error
+INSERT INTO abc VALUES (9)\; ROLLBACK\; INSERT INTO abc VALUES (10)\; ROLLBACK AND CHAIN;  -- 9 rollback, 10 error
+
+-- COMMIT/ROLLBACK AND CHAIN + COMMIT/ROLLBACK
+INSERT INTO abc VALUES (11)\; COMMIT AND CHAIN\; INSERT INTO abc VALUES (12)\; COMMIT;  -- 11 error, 12 not reached
+INSERT INTO abc VALUES (13)\; ROLLBACK AND CHAIN\; INSERT INTO abc VALUES (14)\; ROLLBACK;  -- 13 error, 14 not reached
+
+-- START TRANSACTION + COMMIT/ROLLBACK AND CHAIN
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (15)\; COMMIT AND CHAIN;  -- 15 ok
+SHOW transaction_isolation;  -- transaction is active at this point
+COMMIT;
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (16)\; ROLLBACK AND CHAIN;  -- 16 ok
+SHOW transaction_isolation;  -- transaction is active at this point
+ROLLBACK;
+
+-- START TRANSACTION + COMMIT/ROLLBACK + COMMIT/ROLLBACK AND CHAIN
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (17)\; COMMIT\; INSERT INTO abc VALUES (18)\; COMMIT AND CHAIN;  -- 17 commit, 18 error
+SHOW transaction_isolation;  -- out of transaction block
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ\; INSERT INTO abc VALUES (19)\; ROLLBACK\; INSERT INTO abc VALUES (20)\; ROLLBACK AND CHAIN;  -- 19 rollback, 20 error
+SHOW transaction_isolation;  -- out of transaction block
+
+SELECT * FROM abc ORDER BY 1;
+
+DROP TABLE abc;
+
+
 -- Test for successful cleanup of an aborted transaction at session exit.
 -- THIS MUST BE THE LAST TEST IN THIS FILE.