MDEV-27696 Json table columns accept redundant COLLATE syntax

mysql-test/suite/json/r/json_table.result

@@ -954,5 +954,32 @@ Warnings:
 Warning	1264	Out of range value for column 'converted' at row 2
 Warning	1366	Incorrect integer value: 'foo' for column ``.`(temporary)`.`converted` at row 3
 #
+# MDEV-27696 Json table columns accept redundant COLLATE syntax
+#
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+name BLOB COLLATE `binary` PATH '$.name'
+  )
+) AS jt;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'COLLATE `binary` PATH '$.name'
+  )
+) AS jt' at line 3
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+name VARCHAR(10) COLLATE latin1_bin COLLATE latin1_swedish_ci PATH '$.name'
+  )
+) AS jt;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'COLLATE latin1_swedish_ci PATH '$.name'
+  )
+) AS jt' at line 3
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+name VARCHAR(10) BINARY COLLATE utf8_czech_ci path '$.name'
+  )
+) AS jt;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'COLLATE utf8_czech_ci path '$.name'
+  )
+) AS jt' at line 3
+#
 # End of 10.6 tests
 #

mysql-test/suite/json/t/json_table.test

@@ -814,6 +814,34 @@ select * from json_table('{"a":"foo", "b":1, "c":1000}', '$.*' columns(converted
  
 select * from json_table('{"a":"foo", "b":1, "c":1000}', '$.*' columns(converted tinyint path '$', original text path '$')) as jt order by original;
 
+--echo #
+--echo # MDEV-27696 Json table columns accept redundant COLLATE syntax
+--echo #
+
+--error ER_PARSE_ERROR
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+    name BLOB COLLATE `binary` PATH '$.name'
+  )
+) AS jt;
+
+
+--error ER_PARSE_ERROR
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+    name VARCHAR(10) COLLATE latin1_bin COLLATE latin1_swedish_ci PATH '$.name'
+  )
+) AS jt;
+
+
+--error ER_PARSE_ERROR
+SELECT * FROM json_table('[{"name":"str"}]', '$[*]'
+  COLUMNS (
+    name VARCHAR(10) BINARY COLLATE utf8_czech_ci path '$.name'
+  )
+) AS jt;
+
+
 --echo #
 --echo # End of 10.6 tests
 --echo #

sql/json_table.cc

@@ -851,9 +851,11 @@ TABLE *create_table_for_function(THD *thd, TABLE_LIST *sql_table)
 }
 
 
-int Json_table_column::set(THD *thd, enum_type ctype, const LEX_CSTRING &path)
+int Json_table_column::set(THD *thd, enum_type ctype, const LEX_CSTRING &path,
+                           CHARSET_INFO *cs)
 {
   set(ctype);
+  m_explicit_cs= cs;
   if (json_path_setup(&m_path, thd->variables.collation_connection,
         (const uchar *) path.str, (const uchar *)(path.str + path.length)))
   {

sql/json_table.h

@@ -159,7 +159,7 @@ class Json_table_column : public Sql_alloc
   {
     m_column_type= ctype;
   }
-  int set(THD *thd, enum_type ctype, const LEX_CSTRING &path);
+  int set(THD *thd, enum_type ctype, const LEX_CSTRING &path, CHARSET_INFO *cs);
   Json_table_column(Create_field *f, Json_table_nested_path *nest) :
     m_field(f), m_nest(nest), m_explicit_cs(NULL)
   {

sql/sql_yacc.yy

@@ -200,17 +200,6 @@ void _CONCAT_UNDERSCORED(turn_parser_debug_on,yyparse)()
        MYSQL_YYABORT;                   \
   } while(0)
 
-#define set_collation(X)           \
-  do {  \
-    if (X)  \
-    {  \
-      if (unlikely(Lex->charset && !my_charset_same(Lex->charset,X)))  \
-        my_yyabort_error((ER_COLLATION_CHARSET_MISMATCH, MYF(0),  \
-                          X->coll_name.str,Lex->charset->cs_name.str));  \
-      Lex->charset= X;  \
-    }  \
-  } while(0)
-
 
 %}
 %union {
@@ -1583,6 +1572,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 
 %type <charset>
         opt_collate
+        collate
         charset_name
         charset_or_alias
         charset_name_or_default
@@ -6794,10 +6784,7 @@ charset_or_alias:
           }
         ;
 
-collate: COLLATE_SYM collation_name_or_default
-         {
-           Lex->charset= $2;
-         }
+collate: COLLATE_SYM collation_name_or_default { $$= $2; }
        ;
 
 opt_binary:
@@ -6812,11 +6799,12 @@ binary:
         | BINARY charset_or_alias { bincmp_collation($2, true); }
         | charset_or_alias collate
           {
-            if (!my_charset_same(Lex->charset, $1))
+            if (!my_charset_same($2, $1))
               my_yyabort_error((ER_COLLATION_CHARSET_MISMATCH, MYF(0),
-                                Lex->charset->coll_name.str, $1->cs_name.str));
+                                $2->coll_name.str, $1->cs_name.str));
+            Lex->charset= $2;
           }
-        | collate { }
+        | collate { Lex->charset= $1; }
         ;
 
 opt_bin_mod:
@@ -11629,7 +11617,7 @@ json_table_column_type:
             Lex->last_field->set_attributes(thd, $1, Lex->charset,
                                             COLUMN_DEFINITION_TABLE_FIELD);
             if (Lex->json_table->m_cur_json_table_column->
-                  set(thd, Json_table_column::PATH, $3))
+                  set(thd, Json_table_column::PATH, $3, Lex->charset))
             {
               MYSQL_YYABORT;
             }
@@ -11639,23 +11627,15 @@ json_table_column_type:
             Lex->last_field->set_attributes(thd, $1, Lex->charset,
                                             COLUMN_DEFINITION_TABLE_FIELD);
             Lex->json_table->m_cur_json_table_column->
-              set(thd, Json_table_column::EXISTS_PATH, $4);
+              set(thd, Json_table_column::EXISTS_PATH, $4, Lex->charset);
           }
         ;
 
 json_table_field_type:
           field_type_numeric
         | field_type_temporal
-        | field_type_string opt_collate
-          {
-            set_collation($2);
-            Lex->json_table->m_cur_json_table_column->m_explicit_cs= Lex->charset;
-          }
-        | field_type_lob opt_collate
-          {
-            set_collation($2);
-            Lex->json_table->m_cur_json_table_column->m_explicit_cs= Lex->charset;
-          }
+        | field_type_string
+        | field_type_lob
         ;
 
 json_opt_on_empty_or_error: