An "ITERATE innerLoop" did not work properly inside
a WHILE loop, which itself is inside an outer FOR loop:
outerLoop:
FOR
...
innerLoop:
WHILE
...
ITERATE innerLoop;
...
END WHILE;
...
END FOR;
It erroneously generated an integer increment code for the outer FOR loop.
There were two problems:
1. "ITERATE innerLoop" worked like "ITERATE outerLoop"
2. It was always integer increment, even in case of FOR cursor loops.
Background:
- A FOR loop automatically creates a dedicated sp_pcontext stack entry,
to put the iteration and bound variables on it.
- Other loop types (LOOP, WHILE, REPEAT), do not generate a dedicated
slack entry.
The old code erroneously assumed that sp_pcontext::m_for_loop
either describes the most inner loop (in case the inner loop is FOR),
or is empty (in case the inner loop is not FOR).
But in fact, sp_pcontext::m_for_loop is never empty inside a FOR loop:
it describes the closest FOR loop, even if this FOR loop has nested
non-FOR loops inside.
So when we're near the ITERATE statement in the above script,
sp_pcontext::m_for_loop is not empty - it stores information about
the FOR loop labeled as "outrLoop:".
Fix:
- Adding a new member sp_pcontext::Lex_for_loop::m_start_label,
to remember the explicit or the auto-generated label correspoding
to the start of the FOR body. It's used during generation
of "ITERATE loop_label" code to check if "loop_label" belongs
to the current FOR loop pointed by sp_pcontext::m_for_loop,
or belongs to a non-FOR nested loop.
- Adding LEX methods sp_for_loop_intrange_iterate() and
sp_for_loop_cursor_iterate() to reuse the code between
methods handling:
* ITERATE
* END FOR
- Adding a test for Lex_for_loop::is_for_loop_cursor()
and generate a code either a cursor fetch, or for an integer increment.
Before this change, it always erroneously generated an integer increment
version.
- Cleanup: Initialize Lex_for_loop_st::m_cursor_offset inside
Lex_for_loop_st::init(), to avoid not initialized members.
- Cleanup: Removing a redundant method:
Lex_for_loop_st::init(const Lex_for_loop_st &other)
Using Lex_for_loop_st::operator(const Lex_for_loop_st &other) instead.
This patch includes:
- MDEV-19639 sql_mode=ORACLE: Wrong SHOW PROCEDURE output for sysvar:=expr
- MDEV-19640 Wrong SHOW PROCEDURE output for SET GLOBAL sysvar1=expr, sysvar2=expr
- Preparatory refactoring for MySQL WL#4179
Detailed change list:
1. Changing sp_create_assignment_lex() to accept the position
in the exact query buffer instead of a "bool no_lookahead".
This actually fixes MDEV-19639.
In the previous reduction sp_create_assignment_lex() was
called too late, when the parser went far the from beginning
of the statement, so only a part of the statement got into
sp_instr_stmt.
2. Generating "SET" or "SET GLOBAL" inside sp_create_assignment_instr()
depending on the option type.
This fixes MDEV-19640.
In the previous reduction the code passed (through no_lookahead)
the position of the
word GLOBAL inside sp_create_assignment_lex(), which
worked only for the left-most assignment.
3. Fixing the affected rules to use:
- ident_cli instead of ident
- ident_cli_set_usual_case instead of ident_set_usual_case
4. Changing the input parameter in:
- LEX::set_system_variable()
- LEX::call_statement_start()
- LEX::set_variable()
from just LEX_CSTRING to Lex_ident_sys_st for stricter data type constrol:
to make sure that noone passes an ident_cli
(a fragment of the original query in the client character set)
instead of server-side identifier
(utf8 identifier allocated on THD when needed).
5. Adding Lex_ident_sys() in places where the affected functions are called.
6. Moving all calls of sp_create_assignment_lex() to the places
just before parsing set_expr_or_default.
This makes the grammar clearer, because
sp_create_assignment_lex() and sp_create_assignment_instr()
now stay near each other, so the balance of LEX's push/pop
can be read easier.
This will also help to WL#4179.
7. Adding class sp_lex_set_var
Moving the initialization code from
sp_create_assignment_lex() to the constructor of sp_lex_set_var.
This will also help to WL#4179.
8. Moving a part of the "set" grammar rule into a separate
rule "set_param".
This makes the grammar easier to read and removes
one shift/reduce conflict.
The print() function was missing from the FETCH GROUP NEXT ROW instrunction class, so there was no
output for this particular instruction when we use the query SHOW FUNCTION CODE function_name
