A fix for MDEV-10411 Providing compatibility for basic PL/SQL constructs (Part 6: Assignment operator)

Fixed that a crash in this script:

SET sql_mode=ORACLE;
max_sort_length:= 1024;

mysql-test/suite/compat/oracle/r/variables.result

@@ -0,0 +1,39 @@
+SET sql_mode=oracle;
+#
+# MDEV-10411 Providing compatibility for basic PL/SQL constructs
+# Part 6: Assignment operator
+#
+max_sort_length:=1030;
+SELECT @@max_sort_length;
+@@max_sort_length
+1030
+max_sort_length:=DEFAULT;
+#
+# Testing that SP variables shadow global variables in assignments
+#
+CREATE PROCEDURE p1
+AS
+BEGIN
+max_sort_length:=1030;
+DECLARE
+max_sort_length INT DEFAULT 1031;
+BEGIN
+SELECT @@max_sort_length, max_sort_length;
+max_sort_length:=1032;
+SELECT @@max_sort_length, max_sort_length;
+END;
+SELECT @@max_sort_length;
+max_sort_length:= DEFAULT;
+END;
+$$
+CALL p1();
+@@max_sort_length	max_sort_length
+1030	1031
+@@max_sort_length	max_sort_length
+1030	1032
+@@max_sort_length
+1030
+DROP PROCEDURE p1;
+#
+# End of MDEV-10411 Providing compatibility for basic PL/SQL constructs (part 6)
+#

mysql-test/suite/compat/oracle/t/variables.test

@@ -0,0 +1,38 @@
+SET sql_mode=oracle;
+
+--echo #
+--echo # MDEV-10411 Providing compatibility for basic PL/SQL constructs
+--echo # Part 6: Assignment operator
+--echo #
+
+max_sort_length:=1030;
+SELECT @@max_sort_length;
+max_sort_length:=DEFAULT;
+
+--echo #
+--echo # Testing that SP variables shadow global variables in assignments
+--echo #
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  max_sort_length:=1030;
+  DECLARE
+    max_sort_length INT DEFAULT 1031;
+  BEGIN
+    SELECT @@max_sort_length, max_sort_length;
+    max_sort_length:=1032;
+    SELECT @@max_sort_length, max_sort_length;
+  END;
+  SELECT @@max_sort_length;
+  max_sort_length:= DEFAULT;
+END;
+$$
+DELIMITER ;$$
+CALL p1();
+DROP PROCEDURE p1;
+
+--echo #
+--echo # End of MDEV-10411 Providing compatibility for basic PL/SQL constructs (part 6)
+--echo #

sql/sql_lex.cc

@@ -5922,6 +5922,35 @@ bool LEX::add_resignal_statement(THD *thd, const sp_condition_value *v)
 }
 
 
+/*
+  Perform assignment for a trigger, a system variable, or an SP variable.
+  "variable" be previously set by init_internal_variable(variable, name).
+*/
+bool LEX::set_variable(struct sys_var_with_base *variable, Item *item)
+{
+  if (variable->var == trg_new_row_fake_var)
+  {
+    /* We are in trigger and assigning value to field of new row */
+    return set_trigger_new_row(&variable->base_name, item);
+  }
+  if (variable->var)
+  {
+    /* It is a system variable. */
+    return set_system_variable(variable, option_type, item);
+  }
+
+  /*
+    spcont and spv should not be NULL, as the variable
+    was previously checked by init_internal_variable().
+  */
+  DBUG_ASSERT(spcont);
+  sp_variable *spv= spcont->find_variable(variable->base_name, false);
+  DBUG_ASSERT(spv);
+  /* It is a local variable. */
+  return set_local_variable(spv, item);
+}
+
+
 #ifdef MYSQL_SERVER
 uint binlog_unsafe_map[256];
 

sql/sql_lex.h

@@ -3104,6 +3104,7 @@ public:
                               LEX_STRING dbname, LEX_STRING name);
   bool init_default_internal_variable(struct sys_var_with_base *variable,
                                       LEX_STRING name);
+  bool set_variable(struct sys_var_with_base *variable, Item *item);
   void sp_variable_declarations_init(THD *thd, int nvars);
   bool sp_variable_declarations_finalize(THD *thd, int nvars,
                                          const Column_definition &cdef,

sql/sql_yacc.yy

@@ -14709,29 +14709,8 @@ option_value_following_option_type:
 option_value_no_option_type:
           internal_variable_name equal set_expr_or_default
           {
-            LEX *lex= Lex;
+            if (Lex->set_variable(&$1, $3))
-
+              MYSQL_YYABORT;
-            if ($1.var == trg_new_row_fake_var)
-            {
-              /* We are in trigger and assigning value to field of new row */
-              if (lex->set_trigger_new_row(&$1.base_name, $3))
-                MYSQL_YYABORT;
-            }
-            else if ($1.var)
-            {
-              /* It is a system variable. */
-              if (lex->set_system_variable(&$1, lex->option_type, $3))
-                MYSQL_YYABORT;
-            }
-            else
-            {
-              sp_pcontext *spc= lex->spcont;
-              sp_variable *spv= spc->find_variable($1.base_name, false);
-
-              /* It is a local variable. */
-              if (lex->set_local_variable(spv, $3))
-                MYSQL_YYABORT;
-            }
           }
         | '@' ident_or_text equal expr
           {

sql/sql_yacc_ora.yy

@@ -14599,25 +14599,9 @@ set_assign:
           }
           set_expr_or_default
           {
-            if ($1.var == trg_new_row_fake_var)
+            if (Lex->set_variable(&$1, $4) ||
-            {
+                sp_create_assignment_instr(thd, yychar == YYEMPTY))
-              /* We are in trigger and assigning value to field of new row */
+              MYSQL_YYABORT;
-              if (Lex->set_trigger_new_row(&$1.base_name, $4) ||
-                  Lex->sphead->restore_lex(thd))
-                MYSQL_YYABORT;
-            }
-            else
-            {
-              sp_pcontext *spc= Lex->spcont;
-              sp_variable *spv= spc->find_variable($1.base_name, false);
-
-              /* It is a local variable. */
-              if (Lex->set_local_variable(spv, $4))
-                MYSQL_YYABORT;
-
-              if (sp_create_assignment_instr(thd, yychar == YYEMPTY))
-                MYSQL_YYABORT;
-            }
           }
         ;
 
@@ -14755,29 +14739,8 @@ option_value_following_option_type:
 option_value_no_option_type:
           internal_variable_name equal set_expr_or_default
           {
-            LEX *lex= Lex;
+            if (Lex->set_variable(&$1, $3))
-
+              MYSQL_YYABORT;
-            if ($1.var == trg_new_row_fake_var)
-            {
-              /* We are in trigger and assigning value to field of new row */
-              if (lex->set_trigger_new_row(&$1.base_name, $3))
-                MYSQL_YYABORT;
-            }
-            else if ($1.var)
-            {
-              /* It is a system variable. */
-              if (lex->set_system_variable(&$1, lex->option_type, $3))
-                MYSQL_YYABORT;
-            }
-            else
-            {
-              sp_pcontext *spc= lex->spcont;
-              sp_variable *spv= spc->find_variable($1.base_name, false);
-
-              /* It is a local variable. */
-              if (lex->set_local_variable(spv, $3))
-                MYSQL_YYABORT;
-            }
           }
         | '@' ident_or_text equal expr
           {