An additional patch for MDEV-27690 Crash on `CHARACTER SET csname COLLATE...

An additional patch for MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition

Applying the fix to sql_yacc_ora.yy. Adding a test for sql_mode=ORACLE.

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

 SET sql_mode=ORACLE;
 #
+# Start of 10.2 tests
+#
+#
+# MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition
+#
+CREATE TABLE t1 (a CHAR(10) CHARACTER SET latin1 COLLATE DEFAULT);
+DROP TABLE t1;
+SELECT CAST('a' AS CHAR(10) CHARACTER SET latin1 COLLATE DEFAULT);
+CAST('a' AS CHAR(10) CHARACTER SET latin1 COLLATE DEFAULT)
+a
+SELECT COLUMN_GET(COLUMN_CREATE(0, 'string'),0 AS CHAR CHARACTER SET latin1 COLLATE DEFAULT) AS c1;
+c1
+string
+#
+# End of 10.2 tests
+#
+#
+# Start of 10.3 tests
+#
+#
 # MDEV-12086 sql_mode=ORACLE: allow SELECT UNIQUE as a synonym for SELECT DISTINCT
 #
 CREATE TABLE t1 (a INT);
@@ -10,3 +30,6 @@ a
 20
 30
 DROP TABLE t1;
+#
+# End of 10.3 tests
+#

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

 SET sql_mode=ORACLE;
 
+--echo #
+--echo # Start of 10.2 tests
+--echo #
+
+--echo #
+--echo # MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition
+--echo #
+
+CREATE TABLE t1 (a CHAR(10) CHARACTER SET latin1 COLLATE DEFAULT);
+DROP TABLE t1;
+SELECT CAST('a' AS CHAR(10) CHARACTER SET latin1 COLLATE DEFAULT);
+SELECT COLUMN_GET(COLUMN_CREATE(0, 'string'),0 AS CHAR CHARACTER SET latin1 COLLATE DEFAULT) AS c1;
+
+--echo #
+--echo # End of 10.2 tests
+--echo #
+
+
+
+--echo #
+--echo # Start of 10.3 tests
+--echo #
+
 --echo #
 --echo # MDEV-12086 sql_mode=ORACLE: allow SELECT UNIQUE as a synonym for SELECT DISTINCT
 --echo #
@@ -8,3 +31,8 @@ CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (10),(20),(20),(30),(30),(30);
 SELECT UNIQUE a FROM t1;
 DROP TABLE t1;
+
+
+--echo #
+--echo # End of 10.3 tests
+--echo #

sql/sql_yacc_ora.yy

@@ -1438,6 +1438,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 
 %type <charset>
         opt_collate
+        collate
         charset_name
         charset_or_alias
         charset_name_or_default
@@ -7466,10 +7467,7 @@ charset_or_alias:
           }
         ;
 
-collate: COLLATE_SYM collation_name_or_default
-         {
-           Lex->charset= $2;
-         }
+collate: COLLATE_SYM collation_name_or_default { $$= $2; }
        ;
 
 opt_binary:
@@ -7484,11 +7482,17 @@ binary:
         | BINARY charset_or_alias { bincmp_collation($2, true); }
         | charset_or_alias collate
           {
-            if (!my_charset_same(Lex->charset, $1))
-              my_yyabort_error((ER_COLLATION_CHARSET_MISMATCH, MYF(0),
-                                Lex->charset->name, $1->csname));
+            if (!$2)
+              Lex->charset= $1; // CHARACTER SET cs COLLATE DEFAULT
+            else
+            {
+              if (!my_charset_same($2, $1))
+                my_yyabort_error((ER_COLLATION_CHARSET_MISMATCH, MYF(0),
+                                  $2->name, $1->csname));
+              Lex->charset= $2;
+            }
           }
-        | collate { }
+        | collate { Lex->charset= $1; }
         ;
 
 opt_bin_mod: