MDEV-11952 Oracle-style packages: stage#5mariadb-10.3.5bb-10.3-compatibility

- CREATE PACKAGE [BODY] statements are now
  entirely written to mysql.proc with type='PACKAGE' and type='PACKAGE BODY'.
- CREATE PACKAGE BODY now supports IF NOT EXISTS
- DROP PACKAGE BODY now supports IF EXISTS
- CREATE OR REPLACE PACKAGE [BODY] is now supported
- CREATE PACKAGE [BODY] now support the DEFINER clause:

    CREATE DEFINER user@host PACKAGE pkg ... END;
    CREATE DEFINER user@host PACKAGE BODY pkg ... END;

- CREATE PACKAGE [BODY] now supports SQL SECURITY and COMMENT clauses, e.g.:

    CREATE PACKAGE p1 SQL SECURITY INVOKER COMMENT "comment" AS ... END;

- Package routines are now created from the package CREATE PACKAGE BODY
  statement and don't produce individual records in mysql.proc.

- CREATE PACKAGE BODY now supports package-wide variables.
  Package variables can be read and set inside package routines.
  Package variables are stored in a separate sp_rcontext,
  which is cached in THD on the first packate routine call.

- CREATE PACKAGE BODY now supports the initialization section.

- All public routines (i.e. declared in CREATE PACKAGE)
  must have implementations in CREATE PACKAGE BODY

- Only public package routines are available outside of the package

- {CREATE|DROP} PACKAGE [BODY] now respects CREATE ROUTINE and ALTER ROUTINE
  privileges

- "GRANT EXECUTE ON PACKAGE BODY pkg" is now supported

- SHOW CREATE PACKAGE [BODY] is now supported

- SHOW PACKAGE [BODY] STATUS is now supported

- CREATE and DROP for PACKAGE [BODY] now works for non-current databases

- mysqldump now supports packages

- "SHOW {PROCEDURE|FUNCTION) CODE pkg.routine" now works for package routines

- "SHOW PACKAGE BODY CODE pkg" now works (the package initialization section)

- A new package body level MDL was added

- Recursive calls for package procedures are now possible

- Routine forward declarations in CREATE PACKATE BODY are now supported.

- Package body variables now work as SP OUT parameters

- Package body variables now work as SELECT INTO targets

- Package body variables now support ROW, %ROWTYPE, %TYPE

1 files changed, 2 insertions, 1 deletions

diff --git a/sql/sp_rcontext.h b/sql/sp_rcontext.h
index c4f4cf182da..33d76e1c85a 100644
--- a/sql/sp_rcontext.h
+++ b/sql/sp_rcontext.h
@@ -183,7 +183,8 @@ public:
   uint instr_ptr;
 
   /// The stored program for which this runtime context is created. Used for
-  /// checking if correct runtime context is used for variable handling.
+  /// checking if correct runtime context is used for variable handling,
+  /// and to access the package run-time context.
   /// Also used by slow log.
   const sp_head *m_sp;