WL#15426: Implement SHOW PARSE_TREE [2/3, prep]

Preparatory patch: Add position parameter for parse tree node
constructors. Position info will be later used for generating the SQL
clause to be displayed as a json "text" field in each of the json
parse tree nodes.

Make the @$ parameter mandatory for all classes derived from
Parse_tree_node. This prevents accidental absence of position info
when someone adds a new grammar related PT_* class for a new
production. For this, replaced the default Parse_tree_node constructor
with one taking a single 'pos' parameter of type POS.

While at it, fix some existing clang-tidy issues which were showing up
for lines changed by this patch. Most of them were
cppcoreguidelines-pro-type-member-init.

Change-Id: I8277fcdd2209851783eefc4cb7bc286032879a2a

Author: Amit Khandekar

mysql-test/r/parser.result

@@ -2471,22 +2471,22 @@ x VARCHAR(10)
 COLLATE ascii_bin
 COLLATE ascii_bin
 );
-ERROR 42000: Multiple COLLATE clauses near 'ascii_bin
+ERROR 42000: Multiple COLLATE clauses near 'COLLATE ascii_bin
 )' at line 4
 CREATE TABLE t2 (
 x VARCHAR(10)
 COLLATE ascii_bin
 COLLATE ascii_general_ci
 );
-ERROR 42000: Multiple COLLATE clauses near 'ascii_general_ci
+ERROR 42000: Multiple COLLATE clauses near 'COLLATE ascii_general_ci
 )' at line 4
 CREATE TABLE t3 (
 x VARCHAR(10)
 COLLATE ascii_bin
 NOT NULL
 COLLATE ascii_bin
 );
-ERROR 42000: Multiple COLLATE clauses near 'ascii_bin
+ERROR 42000: Multiple COLLATE clauses near 'COLLATE ascii_bin
 )' at line 5
 CREATE TABLE t3 (
 x VARCHAR(10)
@@ -2504,7 +2504,7 @@ GENERATED ALWAYS AS(NULL)
 COLLATE ascii_bin
 COLLATE ascii_bin
 );
-ERROR 42000: Multiple COLLATE clauses near 'ascii_bin
+ERROR 42000: Multiple COLLATE clauses near 'COLLATE ascii_bin
 )' at line 5
 #
 # Bug#28961997: REMOVE PARENTHESES INFORMATION FROM AST

sql/dd/info_schema/show_query_builder.cc

@@ -62,7 +62,7 @@ Select_lex_builder::Select_lex_builder(const POS *pc, THD *thd)
 bool Select_lex_builder::add_to_select_item_list(Item *expr) {
   // Prepare list if not exist.
   if (!m_select_item_list) {
-    m_select_item_list = new (m_thd->mem_root) PT_select_item_list();
+    m_select_item_list = new (m_thd->mem_root) PT_select_item_list(*m_pos);
 
     if (m_select_item_list == nullptr) return true;
   }
@@ -147,8 +147,9 @@ bool Select_lex_builder::add_from_item(const LEX_CSTRING &schema_name,
   if (table_ident == nullptr) return true;
 
   /* ... FROM schame_name.<table_name> ... */
-  PT_table_factor_table_ident *table_factor = new (m_thd->mem_root)
-      PT_table_factor_table_ident(table_ident, nullptr, NULL_CSTR, nullptr);
+  PT_table_factor_table_ident *table_factor =
+      new (m_thd->mem_root) PT_table_factor_table_ident(
+          *m_pos, table_ident, nullptr, NULL_CSTR, nullptr);
   if (table_factor == nullptr) return true;
 
   if (m_table_reference_list.push_back(table_factor)) return true;
@@ -249,7 +250,7 @@ bool Select_lex_builder::add_condition(Item *a) {
 bool Select_lex_builder::add_order_by(const LEX_CSTRING &field_name) {
   /* ... ORDER BY <field_name> ASC... */
   if (!m_order_by_list) {
-    m_order_by_list = new (m_thd->mem_root) PT_order_list();
+    m_order_by_list = new (m_thd->mem_root) PT_order_list(*m_pos);
     if (m_order_by_list == nullptr) return true;
   }
 
@@ -259,7 +260,7 @@ bool Select_lex_builder::add_order_by(const LEX_CSTRING &field_name) {
   if (ident_field == nullptr) return true;
 
   PT_order_expr *expression =
-      new (m_thd->mem_root) PT_order_expr(ident_field, ORDER_ASC);
+      new (m_thd->mem_root) PT_order_expr(*m_pos, ident_field, ORDER_ASC);
   m_order_by_list->push_back(expression);
 
   return expression == nullptr;
@@ -271,14 +272,14 @@ bool Select_lex_builder::add_order_by(const LEX_CSTRING &field_name) {
 */
 PT_derived_table *Select_lex_builder::prepare_derived_table(
     const LEX_CSTRING &table_alias) {
-  PT_query_primary *query_specification =
-      new (m_thd->mem_root) PT_query_specification(
-          options, m_select_item_list, m_table_reference_list, m_where_clause);
+  PT_query_primary *query_specification = new (m_thd->mem_root)
+      PT_query_specification(*m_pos, options, m_select_item_list,
+                             m_table_reference_list, m_where_clause);
 
   if (query_specification == nullptr) return nullptr;
 
   PT_query_expression *query_expression =
-      new (m_thd->mem_root) PT_query_expression(query_specification);
+      new (m_thd->mem_root) PT_query_expression(*m_pos, query_specification);
   if (query_expression == nullptr) return nullptr;
 
   PT_subquery *sub_query =
@@ -288,7 +289,7 @@ PT_derived_table *Select_lex_builder::prepare_derived_table(
   Create_col_name_list column_names;
   column_names.init(m_thd->mem_root);
   PT_derived_table *derived_table = new (m_thd->mem_root)
-      PT_derived_table(false, sub_query, table_alias, &column_names);
+      PT_derived_table(*m_pos, false, sub_query, table_alias, &column_names);
 
   return derived_table;
 }
@@ -298,19 +299,19 @@ PT_derived_table *Select_lex_builder::prepare_derived_table(
   added to this Select_lex_builder.
 */
 Query_block *Select_lex_builder::prepare_query_block() {
-  PT_query_specification *query_specification =
-      new (m_thd->mem_root) PT_query_specification(
-          options, m_select_item_list, m_table_reference_list, m_where_clause);
+  PT_query_specification *query_specification = new (m_thd->mem_root)
+      PT_query_specification(*m_pos, options, m_select_item_list,
+                             m_table_reference_list, m_where_clause);
   if (query_specification == nullptr) return nullptr;
 
   PT_order *pt_order_by = nullptr;
   if (m_order_by_list) {
-    pt_order_by = new (m_thd->mem_root) PT_order(m_order_by_list);
+    pt_order_by = new (m_thd->mem_root) PT_order(*m_pos, m_order_by_list);
     if (pt_order_by == nullptr) return nullptr;
   }
 
   PT_query_expression *query_expression = new (m_thd->mem_root)
-      PT_query_expression(query_specification, pt_order_by, nullptr);
+      PT_query_expression(*m_pos, query_specification, pt_order_by, nullptr);
   if (query_expression == nullptr) return nullptr;
 
   LEX *lex = m_thd->lex;

sql/item.cc

@@ -137,7 +137,8 @@ void item_init(void) {
 }
 
 Item::Item()
-    : next_free(nullptr),
+    : super(POS()),
+      next_free(nullptr),
       str_value(),
       collation(&my_charset_bin, DERIVATION_COERCIBLE),
       item_name(),
@@ -164,7 +165,8 @@ Item::Item()
 }
 
 Item::Item(THD *thd, const Item *item)
-    : next_free(nullptr),
+    : super(POS()),
+      next_free(nullptr),
       str_value(item->str_value),
       collation(item->collation),
       item_name(item->item_name),
@@ -191,8 +193,9 @@ Item::Item(THD *thd, const Item *item)
   thd->add_item(this);
 }
 
-Item::Item(const POS &)
-    : next_free(nullptr),
+Item::Item(const POS &pos)
+    : super(pos),
+      next_free(nullptr),
       str_value(),
       collation(&my_charset_bin, DERIVATION_COERCIBLE),
       item_name(),

sql/item_create.cc

@@ -129,7 +129,7 @@ namespace {
   @see Function_factory::create_func()
 */
 constexpr auto MAX_ARGLIST_SIZE =
-    std::numeric_limits<decltype(PT_item_list().elements())>::max();
+    std::numeric_limits<decltype(PT_item_list(POS()).elements())>::max();
 
 /**
   Instantiates a function class with the list of arguments.

sql/item_xmlfunc.cc

@@ -391,24 +391,24 @@ class Item_xpath_cast_number : public Item_real_func {
 class Item_nodeset_context_cache : public Item_nodeset_func {
   bool m_is_empty;
   uint32 m_num;
-  uint32 m_pos;
+  uint32 m_position;
   size_t m_size;
 
  public:
   Item_nodeset_context_cache(const ParsedXML &pxml_arg, const CHARSET_INFO *cs)
       : Item_nodeset_func(pxml_arg, cs),
         m_is_empty(true),
         m_num(0),
-        m_pos(0),
+        m_position(0),
         m_size(0) {}
   void val_nodeset(XPathFilter *nodeset) const override {
     nodeset->clear();
     if (!m_is_empty)
-      nodeset->push_back({m_num, m_pos, static_cast<uint>(m_size)});
+      nodeset->push_back({m_num, m_position, static_cast<uint>(m_size)});
   }
   void set_element(uint32 num, uint32 pos, size_t size) {
     m_num = num;
-    m_pos = pos;
+    m_position = pos;
     m_size = size;
     m_is_empty = false;
   }

sql/parse_location.h

@@ -29,8 +29,8 @@
   Helper class for the MY_SQL_PARSER_LTYPE
 */
 struct Symbol_location {
-  const char *start;  // token start
-  const char *end;    // the 1st byte after the token
+  const char *start = nullptr;  // token start
+  const char *end = nullptr;    // the 1st byte after the token
 
   bool is_empty() const { return length() == 0; }
   size_t length() const { return static_cast<size_t>(end - start); }