MDEV-15941 Explicit cursor FOR loop does not close the cursor

mysql-test/main/sp-code.result

@@ -1113,23 +1113,26 @@ Pos	Instruction
 10	stmt 0 "SELECT rec1.a, rec1.b"
 11	cfetch cur1@1 rec1@0
 12	jump 6
-13	cursor_copy_struct cur0 rec0@1
-14	copen cur0@0
-15	cfetch cur0@0 rec0@1
-16	jump_if_not 21(21) `cur0`%FOUND
-17	set rec0.a@1["a"] 10
-18	set rec0.b@1["b"] 'b0'
-19	cfetch cur0@0 rec0@1
-20	jump 16
-21	cursor_copy_struct cur2 rec2@2
-22	copen cur2@2
-23	cfetch cur2@2 rec2@2
-24	jump_if_not 29(29) `cur2`%FOUND
-25	set rec2.a@2["a"] 10
-26	set rec2.b@2["b"] 'b0'
-27	cfetch cur2@2 rec2@2
-28	jump 24
-29	cpop 3
+13	cclose cur1@1
+14	cursor_copy_struct cur0 rec0@1
+15	copen cur0@0
+16	cfetch cur0@0 rec0@1
+17	jump_if_not 22(22) `cur0`%FOUND
+18	set rec0.a@1["a"] 10
+19	set rec0.b@1["b"] 'b0'
+20	cfetch cur0@0 rec0@1
+21	jump 17
+22	cclose cur0@0
+23	cursor_copy_struct cur2 rec2@2
+24	copen cur2@2
+25	cfetch cur2@2 rec2@2
+26	jump_if_not 31(31) `cur2`%FOUND
+27	set rec2.a@2["a"] 10
+28	set rec2.b@2["b"] 'b0'
+29	cfetch cur2@2 rec2@2
+30	jump 26
+31	cclose cur2@2
+32	cpop 3
 DROP PROCEDURE p1;
 # Nested explicit cursor FOR loops
 CREATE PROCEDURE p1()
@@ -1164,14 +1167,14 @@ Pos	Instruction
 1	cursor_copy_struct cur0 rec0@0
 2	copen cur0@0
 3	cfetch cur0@0 rec0@0
-4	jump_if_not 29(29) `cur0`%FOUND
+4	jump_if_not 31(31) `cur0`%FOUND
 5	cpush cur1@1
 6	set rec0.a@0["a"] 11
 7	set rec0.b@0["b"] 'b0'
 8	cursor_copy_struct cur1 rec1@1
 9	copen cur1@1
 10	cfetch cur1@1 rec1@1
-11	jump_if_not 26(26) `cur1`%FOUND
+11	jump_if_not 27(27) `cur1`%FOUND
 12	set rec1.a@1["a"] 11
 13	set rec1.b@1["b"] 'b1'
 14	cpush cur2@2
@@ -1183,13 +1186,16 @@ Pos	Instruction
 20	set rec2.b@2["b"] 'b2'
 21	cfetch cur2@2 rec2@2
 22	jump 18
-23	cpop 1
-24	cfetch cur1@1 rec1@1
-25	jump 11
-26	cpop 1
-27	cfetch cur0@0 rec0@0
-28	jump 4
-29	cpop 1
+23	cclose cur2@2
+24	cpop 1
+25	cfetch cur1@1 rec1@1
+26	jump 11
+27	cclose cur1@1
+28	cpop 1
+29	cfetch cur0@0 rec0@0
+30	jump 4
+31	cclose cur0@0
+32	cpop 1
 DROP PROCEDURE p1;
 # Implicit cursor FOR loops
 CREATE PROCEDURE p1()

mysql-test/main/sp-cursor.result

@@ -611,3 +611,76 @@ a	b
 a	b
 2	b2
 DROP TABLE t1;
+#
+# MDEV-15941 Explicit cursor FOR loop does not close the cursor
+#
+BEGIN NOT ATOMIC
+DECLARE v INT;
+DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+FETCH cur INTO v;
+END;
+$$
+rec.a
+1
+ERROR 24000: Cursor is not open
+BEGIN NOT ATOMIC
+DECLARE v INT;
+DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+label:
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+FETCH cur INTO v;
+END;
+$$
+rec.a
+1
+ERROR 24000: Cursor is not open
+BEGIN NOT ATOMIC
+DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+OPEN cur;
+FOR rec IN cur DO
+SELECT rec.a;
+END FOR;
+END;
+$$
+ERROR 24000: Cursor is already open
+BEGIN NOT ATOMIC
+DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+END;
+$$
+rec.a
+1
+rec.a
+1
+BEGIN NOT ATOMIC
+DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+label1:
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+label2:
+FOR rec IN cur
+DO
+SELECT rec.a;
+END FOR;
+END;
+$$
+rec.a
+1
+rec.a
+1

mysql-test/main/sp-cursor.test

@@ -607,3 +607,85 @@ END;
 $$
 DELIMITER ;$$
 DROP TABLE t1;
+
+
+--echo #
+--echo # MDEV-15941 Explicit cursor FOR loop does not close the cursor
+--echo #
+
+DELIMITER $$;
+--error ER_SP_CURSOR_NOT_OPEN
+BEGIN NOT ATOMIC
+  DECLARE v INT;
+  DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+  FETCH cur INTO v;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_SP_CURSOR_NOT_OPEN
+BEGIN NOT ATOMIC
+  DECLARE v INT;
+  DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+label:
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+  FETCH cur INTO v;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_SP_CURSOR_ALREADY_OPEN
+BEGIN NOT ATOMIC
+  DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+  OPEN cur;
+  FOR rec IN cur DO
+    SELECT rec.a;
+  END FOR;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+BEGIN NOT ATOMIC
+  DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+BEGIN NOT ATOMIC
+  DECLARE cur CURSOR FOR SELECT 1 AS a FROM DUAL;
+label1:
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+label2:
+  FOR rec IN cur
+  DO
+    SELECT rec.a;
+  END FOR;
+END;
+$$
+DELIMITER ;$$

mysql-test/suite/compat/oracle/r/sp-code.result

@@ -1084,23 +1084,26 @@ Pos	Instruction
 10	stmt 0 "SELECT rec1.a, rec1.b"
 11	cfetch cur1@1 rec1@0
 12	jump 6
-13	cursor_copy_struct cur0 rec0@1
-14	copen cur0@0
-15	cfetch cur0@0 rec0@1
-16	jump_if_not 21(21) "cur0"%FOUND
-17	set rec0.a@1["a"] 10
-18	set rec0.b@1["b"] 'b0'
-19	cfetch cur0@0 rec0@1
-20	jump 16
-21	cursor_copy_struct cur2 rec2@2
-22	copen cur2@2
-23	cfetch cur2@2 rec2@2
-24	jump_if_not 29(29) "cur2"%FOUND
-25	set rec2.a@2["a"] 10
-26	set rec2.b@2["b"] 'b0'
-27	cfetch cur2@2 rec2@2
-28	jump 24
-29	cpop 3
+13	cclose cur1@1
+14	cursor_copy_struct cur0 rec0@1
+15	copen cur0@0
+16	cfetch cur0@0 rec0@1
+17	jump_if_not 22(22) "cur0"%FOUND
+18	set rec0.a@1["a"] 10
+19	set rec0.b@1["b"] 'b0'
+20	cfetch cur0@0 rec0@1
+21	jump 17
+22	cclose cur0@0
+23	cursor_copy_struct cur2 rec2@2
+24	copen cur2@2
+25	cfetch cur2@2 rec2@2
+26	jump_if_not 31(31) "cur2"%FOUND
+27	set rec2.a@2["a"] 10
+28	set rec2.b@2["b"] 'b0'
+29	cfetch cur2@2 rec2@2
+30	jump 26
+31	cclose cur2@2
+32	cpop 3
 DROP PROCEDURE p1;
 CREATE PROCEDURE p1
 AS
@@ -1137,14 +1140,14 @@ Pos	Instruction
 1	cursor_copy_struct cur0 rec0@0
 2	copen cur0@0
 3	cfetch cur0@0 rec0@0
-4	jump_if_not 29(29) "cur0"%FOUND
+4	jump_if_not 31(31) "cur0"%FOUND
 5	cpush cur1@1
 6	set rec0.a@0["a"] 11
 7	set rec0.b@0["b"] 'b0'
 8	cursor_copy_struct cur1 rec1@1
 9	copen cur1@1
 10	cfetch cur1@1 rec1@1
-11	jump_if_not 26(26) "cur1"%FOUND
+11	jump_if_not 27(27) "cur1"%FOUND
 12	set rec1.a@1["a"] 11
 13	set rec1.b@1["b"] 'b1'
 14	cpush cur2@2
@@ -1156,13 +1159,16 @@ Pos	Instruction
 20	set rec2.b@2["b"] 'b2'
 21	cfetch cur2@2 rec2@2
 22	jump 18
-23	cpop 1
-24	cfetch cur1@1 rec1@1
-25	jump 11
-26	cpop 1
-27	cfetch cur0@0 rec0@0
-28	jump 4
-29	cpop 1
+23	cclose cur2@2
+24	cpop 1
+25	cfetch cur1@1 rec1@1
+26	jump 11
+27	cclose cur1@1
+28	cpop 1
+29	cfetch cur0@0 rec0@0
+30	jump 4
+31	cclose cur0@0
+32	cpop 1
 DROP PROCEDURE p1;
 #
 # MDEV-12098 sql_mode=ORACLE: Implicit cursor FOR loop

mysql-test/suite/compat/oracle/r/sp-cursor-rowtype.result

@@ -1331,6 +1331,93 @@ rec2.a	rec2.b
 DROP PROCEDURE p1;
 DROP TABLE t1;
 #
+# MDEV-15941 Explicit cursor FOR loop does not close the cursor
+#
+DECLARE
+CURSOR cur IS SELECT 1 AS a FROM DUAL;
+v INT;
+BEGIN
+FOR rec IN cur
+LOOP
+NULL;
+END LOOP;
+FETCH cur INTO v;
+END;
+$$
+ERROR 24000: Cursor is not open
+DECLARE
+CURSOR cur IS SELECT 1 AS a FROM DUAL;
+v INT;
+BEGIN
+<<label>>
+FOR rec IN cur
+LOOP
+NULL;
+END LOOP label;
+FETCH cur INTO v;
+END;
+$$
+ERROR 24000: Cursor is not open
+DECLARE
+CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+OPEN cur;
+FOR rec IN cur
+LOOP
+NULL;
+END LOOP;
+END;
+$$
+ERROR 24000: Cursor is already open
+DECLARE
+CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+FOR rec IN cur
+LOOP
+SELECT rec.a;
+END LOOP;
+SELECT cur%ISOPEN;
+FOR rec IN cur
+LOOP
+SELECT rec.a;
+END LOOP;
+SELECT cur%ISOPEN;
+END;
+$$
+rec.a
+1
+cur%ISOPEN
+0
+rec.a
+1
+cur%ISOPEN
+0
+DECLARE
+CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+<<label1>>
+FOR rec IN cur
+LOOP
+SELECT rec.a;
+END LOOP label1;
+SELECT cur%ISOPEN;
+<<label2>>
+FOR rec IN cur
+LOOP
+SELECT rec.a;
+END LOOP;
+SELECT cur%ISOPEN;
+END;
+$$
+rec.a
+1
+cur%ISOPEN
+0
+rec.a
+1
+cur%ISOPEN
+0
+#
 # MDEV-14139 Anchored data types for variables
 #
 DECLARE

mysql-test/suite/compat/oracle/t/sp-cursor-rowtype.test

@@ -1424,6 +1424,98 @@ DROP PROCEDURE p1;
 DROP TABLE t1;
 
 
+--echo #
+--echo # MDEV-15941 Explicit cursor FOR loop does not close the cursor
+--echo #
+
+DELIMITER $$;
+--error ER_SP_CURSOR_NOT_OPEN
+DECLARE
+  CURSOR cur IS SELECT 1 AS a FROM DUAL;
+  v INT;
+BEGIN
+  FOR rec IN cur
+  LOOP
+    NULL;
+  END LOOP;
+  FETCH cur INTO v;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_SP_CURSOR_NOT_OPEN
+DECLARE
+  CURSOR cur IS SELECT 1 AS a FROM DUAL;
+  v INT;
+BEGIN
+<<label>>
+  FOR rec IN cur
+  LOOP
+    NULL;
+  END LOOP label;
+  FETCH cur INTO v;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_SP_CURSOR_ALREADY_OPEN
+DECLARE
+  CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+  OPEN cur;
+  FOR rec IN cur
+  LOOP
+    NULL;
+  END LOOP;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+DECLARE
+  CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+  FOR rec IN cur
+  LOOP
+    SELECT rec.a;
+  END LOOP;
+  SELECT cur%ISOPEN;
+  FOR rec IN cur
+  LOOP
+    SELECT rec.a;
+  END LOOP;
+  SELECT cur%ISOPEN;
+END;
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+DECLARE
+  CURSOR cur IS SELECT 1 AS a FROM DUAL;
+BEGIN
+<<label1>>
+  FOR rec IN cur
+  LOOP
+    SELECT rec.a;
+  END LOOP label1;
+  SELECT cur%ISOPEN;
+<<label2>>
+  FOR rec IN cur
+  LOOP
+    SELECT rec.a;
+  END LOOP;
+  SELECT cur%ISOPEN;
+END;
+$$
+DELIMITER ;$$
+
+
 --echo #
 --echo # MDEV-14139 Anchored data types for variables
 --echo #

sql/sql_lex.cc

@@ -5891,6 +5891,26 @@ bool LEX::sp_for_loop_cursor_finalize(THD *thd, const Lex_for_loop_st &loop)
   return sp_while_loop_finalize(thd);
 }
 
+bool LEX::sp_for_loop_outer_block_finalize(THD *thd,
+                                           const Lex_for_loop_st &loop)
+{
+  Lex_spblock tmp;
+  tmp.curs= MY_TEST(loop.m_implicit_cursor);
+  if (unlikely(sp_block_finalize(thd, tmp))) // The outer DECLARE..BEGIN..END
+    return true;
+  if (!loop.is_for_loop_explicit_cursor())
+    return false;
+  /*
+    Explicit cursor FOR loop must close the cursor automatically.
+    Note, implicit cursor FOR loop does not need to close the cursor,
+    it's closed by sp_instr_cpop.
+  */
+  sp_instr_cclose *ic= new (thd->mem_root)
+                       sp_instr_cclose(sphead->instructions(), spcont,
+                                       loop.m_cursor_offset);
+  return ic == NULL || sphead->add_instr(ic);
+}
+
 /***************************************************************************/
 
 bool LEX::sp_declare_cursor(THD *thd, const LEX_CSTRING *name,

sql/sql_lex.h

@@ -3802,6 +3802,7 @@ public:
            sp_for_loop_cursor_finalize(thd, loop) :
            sp_for_loop_intrange_finalize(thd, loop);
   }
+  bool sp_for_loop_outer_block_finalize(THD *thd, const Lex_for_loop_st &loop);
   /* End of FOR LOOP methods */
 
   bool add_signal_statement(THD *thd, const class sp_condition_value *value);

sql/sql_yacc.yy

@@ -4729,9 +4729,7 @@ sp_labeled_control:
           }
           pop_sp_loop_label                    // The inner WHILE block
           {
-            Lex_spblock tmp;
-            tmp.curs= MY_TEST($4.m_implicit_cursor);
-            if (unlikely(Lex->sp_block_finalize(thd, tmp))) // The outer DECLARE..BEGIN..END
+            if (unlikely(Lex->sp_for_loop_outer_block_finalize(thd, $4)))
               MYSQL_YYABORT;
           }
         | sp_label REPEAT_SYM
@@ -4781,12 +4779,10 @@ sp_unlabeled_control:
           sp_proc_stmts1
           END FOR_SYM
           {
-            Lex_spblock tmp;
-            tmp.curs= MY_TEST($3.m_implicit_cursor);
             if (unlikely(Lex->sp_for_loop_finalize(thd, $3)))
               MYSQL_YYABORT;
             Lex->sp_pop_loop_empty_label(thd); // The inner WHILE block
-            if (unlikely(Lex->sp_block_finalize(thd, tmp))) // The outer DECLARE..BEGIN..END
+            if (unlikely(Lex->sp_for_loop_outer_block_finalize(thd, $3)))
               MYSQL_YYABORT;
           }
         | REPEAT_SYM

sql/sql_yacc_ora.yy

@@ -4676,9 +4676,7 @@ sp_labeled_control:
           }
           pop_sp_loop_label                    // The inner WHILE block
           {
-            Lex_spblock tmp;
-            tmp.curs= MY_TEST($4.m_implicit_cursor);
-            if (unlikely(Lex->sp_block_finalize(thd, tmp))) // The outer DECLARE..BEGIN..END
+            if (unlikely(Lex->sp_for_loop_outer_block_finalize(thd, $4)))
               MYSQL_YYABORT;
           }
         | labels_declaration_oracle REPEAT_SYM
@@ -4728,12 +4726,10 @@ sp_unlabeled_control:
           sp_proc_stmts1
           END LOOP_SYM
           {
-            Lex_spblock tmp;
-            tmp.curs= MY_TEST($3.m_implicit_cursor);
             if (unlikely(Lex->sp_for_loop_finalize(thd, $3)))
               MYSQL_YYABORT;
             Lex->sp_pop_loop_empty_label(thd); // The inner WHILE block
-            if (unlikely(Lex->sp_block_finalize(thd, tmp))) // The outer DECLARE..BEGIN..END
+            if (unlikely(Lex->sp_for_loop_outer_block_finalize(thd, $3)))
               MYSQL_YYABORT;
           }
         | REPEAT_SYM

sql/structs.h

@@ -720,6 +720,10 @@ public:
     *this= other;
   }
   bool is_for_loop_cursor() const { return m_upper_bound == NULL; }
+  bool is_for_loop_explicit_cursor() const
+  {
+    return is_for_loop_cursor() && !m_implicit_cursor;
+  }
 };