Add support of package removal rollback

README.md

@@ -304,8 +304,8 @@ SELECT pgv_get('pack', 'var_text', NULL::text);
  before transaction block
 ```
 
-If you create variable after `BEGIN` or `SAVEPOINT` statements and than rollback
-to previous state - variable will not be exist:
+If you create a transactional variable after `BEGIN` or `SAVEPOINT` statements 
+and then rollback to previous state - variable will not be exist:
 
 ```sql
 BEGIN;
@@ -324,15 +324,33 @@ ERROR:  unrecognized variable "var_int"
 COMMIT;
 ```
 
-Also you cannot undo removing variable by `ROLLBACK`:
+You can undo removal of a transactional variable by `ROLLBACK`, but if you remove
+a whole package, all regular variables will be removed permanently:
 
 ```sql
-SELECT pgv_set('pack', 'var_int', 122, true);
+SELECT pgv_set('pack', 'var_reg', 123);
+SELECT pgv_set('pack', 'var_trans', 456, true);
 BEGIN;
 SELECT pgv_free();
+SELECT * FROM pgv_list();
+ package | name | is_transactional
+---------+------+------------------
+(0 rows)
+
+-- Memory is allocated yet
+SELECT * FROM pgv_stats();
+ package | allocated_memory
+---------+------------------
+ pack    |            24576
+(1 row)
+
 ROLLBACK;
-SELECT pgv_get('pack', 'var_int', NULL::int);
-ERROR:  unrecognized package "pack"
+SELECT * FROM pgv_list();
+ package |   name    | is_transactional
+---------+-----------+------------------
+ pack    | var_trans | t
+(1 row)
+
 ```
 
 If you created transactional variable once, you should use flag `is_transactional`

expected/pg_variables_trans.out

@@ -1392,7 +1392,7 @@ SELECT pgv_free();
 
 (1 row)
 
---Additional tests
+-- Additional tests
 SELECT pgv_insert('vars3', 'r1', tab, true) FROM tab;
  pgv_insert 
 ------------
@@ -1598,3 +1598,243 @@ BEGIN;
 SELECT pgv_set('vars', 'any1', 'wrong type'::varchar, true);
 ERROR:  variable "any1" requires "text" value
 COMMIT;
+-- THE REMOVAL OF THE VARIABLE MUST BE CANCELED ON ROLLBACK
+SELECT pgv_set('vars', 'any1', 'variable exists'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+BEGIN;
+SELECT pgv_remove('vars', 'any1');
+ pgv_remove 
+------------
+
+(1 row)
+
+SELECT pgv_exists('vars', 'any1');
+ pgv_exists 
+------------
+ f
+(1 row)
+
+ROLLBACK;
+SELECT pgv_exists('vars', 'any1');
+ pgv_exists 
+------------
+ t
+(1 row)
+
+SELECT pgv_get('vars', 'any1',NULL::text);
+     pgv_get     
+-----------------
+ variable exists
+(1 row)
+
+BEGIN;
+SELECT pgv_remove('vars', 'any1');
+ pgv_remove 
+------------
+
+(1 row)
+
+SELECT pgv_exists('vars', 'any1');
+ pgv_exists 
+------------
+ f
+(1 row)
+
+COMMIT;
+SELECT pgv_exists('vars', 'any1');
+ pgv_exists 
+------------
+ f
+(1 row)
+
+SELECT pgv_get('vars', 'any1',NULL::text);
+ERROR:  unrecognized variable "any1"
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+ vars3   | r1   | t
+(1 row)
+
+BEGIN;
+SELECT pgv_free();
+ pgv_free 
+----------
+
+(1 row)
+
+ROLLBACK;
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+ vars3   | r1   | t
+(1 row)
+
+BEGIN;
+SELECT pgv_free();
+ pgv_free 
+----------
+
+(1 row)
+
+COMMIT;
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+SELECT pgv_set('vars', 'regular', 'regular variable exists'::text);
+ pgv_set 
+---------
+
+(1 row)
+
+SELECT pgv_set('vars', 'trans1', 'trans1 variable exists'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+BEGIN;
+SELECT pgv_free();
+ pgv_free 
+----------
+
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+SELECT pgv_set('vars', 'trans2', 'trans2 variable exists'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package |  name  | is_transactional 
+---------+--------+------------------
+ vars    | trans2 | t
+(1 row)
+
+SELECT pgv_remove('vars');
+ pgv_remove 
+------------
+
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+ROLLBACK;
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package |  name  | is_transactional 
+---------+--------+------------------
+ vars    | trans1 | t
+(1 row)
+
+BEGIN;
+SAVEPOINT sp1;
+SAVEPOINT sp2;
+SAVEPOINT sp3;
+SELECT pgv_set('vars2', 'trans2', 'trans2 variable exists'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+SAVEPOINT sp4;
+SAVEPOINT sp5;
+SELECT pgv_free();
+ pgv_free 
+----------
+
+(1 row)
+
+SELECT package FROM pgv_stats();
+ package 
+---------
+ vars2
+ vars
+(2 rows)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+RELEASE sp5;
+SELECT package FROM pgv_stats();
+ package 
+---------
+ vars2
+ vars
+(2 rows)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+RELEASE sp4;
+SELECT package FROM pgv_stats();
+ package 
+---------
+ vars
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+COMMIT;
+SELECT package FROM pgv_stats();
+ package 
+---------
+(0 rows)
+
+BEGIN;
+SELECT pgv_set('vars', 'trans1', 'package created'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+SELECT pgv_remove('vars');
+ pgv_remove 
+------------
+
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package | name | is_transactional 
+---------+------+------------------
+(0 rows)
+
+SELECT pgv_set('vars', 'trans1', 'package restored'::text, true);
+ pgv_set 
+---------
+
+(1 row)
+
+SELECT * FROM pgv_list() ORDER BY package, name;
+ package |  name  | is_transactional 
+---------+--------+------------------
+ vars    | trans1 | t
+(1 row)
+
+COMMIT;
+SELECT pgv_remove('vars');
+ pgv_remove 
+------------
+
+(1 row)
+