Bug#35964157 mysql 8.1.0/8.2.0, mysqld got signal 11, when send sql, show parse_tre

SHOW PARSE_TREE is only supported for SELECT statements.
Return ER_NOT_SUPPORTED_YET for all other kinds of statements.

Change-Id: I994af8dee925936fba3beb042d70ba9bba3caf3c

Author: Tor Didriksen

mysql-test/r/show_parse_tree.result

@@ -2577,3 +2577,11 @@ SHOW PARSE_TREE CREATE TABLE tab(id INT);
 ERROR 42000: This version of MySQL doesn't yet support 'Parse tree display of this statement'
 SHOW PARSE_TREE CREATE TABLE tab(id INVALID_SYNTAX);
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INVALID_SYNTAX)' at line 1
+#
+# Bug#35964157 mysql 8.1.0/8.2.0, mysqld got signal 11,
+#              when send sql, show parse_tre
+#
+SHOW PARSE_TREE SET @b:=(SELECT a FROM t);
+ERROR 42000: This version of MySQL doesn't yet support 'Parse tree display of this statement'
+SHOW PARSE_TREE CREATE SCHEMA s1;
+ERROR 42000: This version of MySQL doesn't yet support 'Parse tree display of this statement'

mysql-test/t/show_parse_tree.test

@@ -58,3 +58,14 @@ SHOW PARSE_TREE UPDATE tab SET O = 1;
 SHOW PARSE_TREE CREATE TABLE tab(id INT);
 --error ER_PARSE_ERROR
 SHOW PARSE_TREE CREATE TABLE tab(id INVALID_SYNTAX);
+
+--echo #
+--echo # Bug#35964157 mysql 8.1.0/8.2.0, mysqld got signal 11,
+--echo #              when send sql, show parse_tre
+--echo #
+
+--error ER_NOT_SUPPORTED_YET
+SHOW PARSE_TREE SET @b:=(SELECT a FROM t);
+
+--error ER_NOT_SUPPORTED_YET
+SHOW PARSE_TREE CREATE SCHEMA s1;

sql/parse_tree_nodes.cc

@@ -4682,6 +4682,12 @@ Sql_cmd *PT_show_grants::make_cmd(THD *thd) {
 Sql_cmd *PT_show_parse_tree::make_cmd(THD *thd) {
   LEX *lex = thd->lex;
 
+  // Several of the 'simple_statement:' do $$= nullptr;
+  if (m_parse_tree_stmt == nullptr) {
+    // my_error(ER_NOT_SUPPORTED_YET ....)
+    Parse_tree_root::get_printable_parse_tree(thd);
+    return nullptr;
+  }
   std::string parse_tree_str = m_parse_tree_stmt->get_printable_parse_tree(thd);
 
   if (parse_tree_str.empty()) return nullptr;