Bug #34240108 Remove if __cplusplus > 201100L from public headers

This is a followup to the patch for:
Bug #34231639 compile error with the newest Visual studio 2022
where inconsistent such #if __cplusplus tests broke the build.

We always build our own code with -std=c++17. However, we cannot
assume that client/customer code builds with any specific C++
standard.

Remove the : int specifier for enum_field_types. It is the default
anyways, and we do not want any difference for C/C++ code.

Remove the nullptr initialization of members of 'struct LIST'.  This
struct is mostly used in legacy code for myisam, and this code does
not depend on CTORs or initializers.

We also add a which verifies that our public headers do not contain
any C++14 or C++17 features.

Change-Id: I15b350e09c5d0fa478cde1e74eed240d4d018c0c

Author: Tor Didriksen

Diff for: include/CMakeLists.txt

@@ -20,6 +20,8 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 
+DISABLE_MISSING_PROFILE_WARNING()
+
 # These are the headers required to #include <mysql.h>, which we ship
 # to the client as part of our API.
 #
@@ -61,3 +63,29 @@ IF (WIN32 AND OPENSSL_APPLINK_C)
     COMPONENT Development
     )
 ENDIF()
+
+SET(INSTALLED_HEADERS_CC ${CMAKE_CURRENT_BINARY_DIR}/installed_headers.cc)
+SET(INSTALLED_HEADERS_CONTENT "")
+FOREACH(HEADER ${HEADERS} ${HEADERS_MYSQL_DIR})
+  STRING_APPEND(INSTALLED_HEADERS_CONTENT "#include \"${HEADER}\"")
+  STRING_APPEND(INSTALLED_HEADERS_CONTENT "\n")
+ENDFOREACH()
+STRING_APPEND(INSTALLED_HEADERS_CONTENT
+  "int main(int, char **) { return 0; }"
+  )
+
+CONFIGURE_FILE_CONTENT("${INSTALLED_HEADERS_CONTENT}"
+  ${INSTALLED_HEADERS_CC}
+  )
+
+# Verifies that all installed headers comply with -std=c++11
+# i.e. no c++17 features used.
+# VS/clang on windows do not accept /std:c++11
+MYSQL_ADD_EXECUTABLE(installed_headers
+  ${INSTALLED_HEADERS_CC}
+  DEPENDENCIES GenError
+  SKIP_INSTALL
+  )
+# This will add -std=gnu++11 for compilers which support it.
+# It will be silently ignored on Windows.
+SET_PROPERTY(TARGET installed_headers PROPERTY CXX_STANDARD 11)

Diff for: include/field_types.h

@@ -49,12 +49,8 @@ extern "C" {
 /**
   Column types for MySQL
 */
-enum enum_field_types
-#if defined(__cplusplus)
-    // N2764: Forward enum declarations, added in C++11
-    : int
-#endif /* __cplusplus */
-{ MYSQL_TYPE_DECIMAL,
+enum enum_field_types {
+  MYSQL_TYPE_DECIMAL,
   MYSQL_TYPE_TINY,
   MYSQL_TYPE_SHORT,
   MYSQL_TYPE_LONG,
@@ -87,7 +83,8 @@ enum enum_field_types
   MYSQL_TYPE_BLOB = 252,
   MYSQL_TYPE_VAR_STRING = 253,
   MYSQL_TYPE_STRING = 254,
-  MYSQL_TYPE_GEOMETRY = 255 };
+  MYSQL_TYPE_GEOMETRY = 255
+};
 
 #ifdef __cplusplus
 }  // extern "C"

Diff for: include/my_list.h

@@ -25,21 +25,16 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
-#ifndef _list_h_
-#define _list_h_
+#ifndef MY_LIST_INCLUDED
+#define MY_LIST_INCLUDED
 
 /**
   @file include/my_list.h
 */
 
 typedef struct LIST {
-#if defined(__cplusplus) && __cplusplus >= 201103L
-  struct LIST *prev{nullptr}, *next{nullptr};
-  void *data{nullptr};
-#else
   struct LIST *prev, *next;
   void *data;
-#endif
 } LIST;
 
 typedef int (*list_walk_action)(void *, void *);
@@ -54,4 +49,4 @@ extern int list_walk(LIST *, list_walk_action action, unsigned char *argument);
 
 #define list_rest(a) ((a)->next)
 
-#endif
+#endif  // MY_LIST_INCLUDED

Diff for: include/my_time.h

@@ -48,11 +48,10 @@
 #include <winsock2.h>  // struct timeval
 #endif                 /* _WIN32 */
 
+#include "field_types.h"
 #include "my_time_t.h"
 #include "mysql_time.h"  // struct MYSQL_TIME, shared with client code
 
-enum enum_field_types : int;
-
 extern const unsigned long long int log_10_int[20];
 extern const unsigned char days_in_month[];
 extern const char my_zero_datetime6[]; /* "0000-00-00 00:00:00.000000" */

Diff for: include/mysql.h.pp

@@ -1,8 +1,8 @@
 typedef uint64_t my_ulonglong;
 typedef int my_socket;
 #include "field_types.h"
-enum enum_field_types
-{ MYSQL_TYPE_DECIMAL,
+enum enum_field_types {
+  MYSQL_TYPE_DECIMAL,
   MYSQL_TYPE_TINY,
   MYSQL_TYPE_SHORT,
   MYSQL_TYPE_LONG,
@@ -35,7 +35,8 @@
   MYSQL_TYPE_BLOB = 252,
   MYSQL_TYPE_VAR_STRING = 253,
   MYSQL_TYPE_STRING = 254,
-  MYSQL_TYPE_GEOMETRY = 255 };
+  MYSQL_TYPE_GEOMETRY = 255
+};
 typedef enum enum_field_types enum_field_types;
 #include "my_list.h"
 typedef struct LIST {

Diff for: include/thr_lock.h

@@ -136,7 +136,7 @@ struct st_lock_list {
 };
 
 struct THR_LOCK {
-  LIST list;
+  LIST list{nullptr, nullptr, nullptr};
   mysql_mutex_t mutex;
   struct st_lock_list read_wait;
   struct st_lock_list read;

Diff for: libbinlogevents/export/binary_log_funcs.h

@@ -28,14 +28,8 @@
 #ifndef BINARY_LOG_FUNCS_INCLUDED
 #define BINARY_LOG_FUNCS_INCLUDED
 
-// We use cstdint if this is 2011 standard (or later)
-#if __cplusplus > 201100L
-#include <cstdint>
-enum enum_field_types : int;
-#else
 #include <stdint.h>
 #include "field_types.h"  // enum_field_types
-#endif
 
 #ifdef __cplusplus
 extern "C" {

Diff for: mysys/list.cc

@@ -75,8 +75,8 @@ void list_free(LIST *root, uint free_data) {
 }
 
 LIST *list_cons(void *data, LIST *list) {
-  LIST *new_charset =
-      (LIST *)my_malloc(key_memory_LIST, sizeof(LIST), MYF(MY_FAE));
+  LIST *new_charset = (LIST *)my_malloc(key_memory_LIST, sizeof(LIST),
+                                        MYF(MY_FAE | MY_ZEROFILL));
   if (!new_charset) return nullptr;
   new_charset->data = data;
   return list_add(list, new_charset);

Diff for: sql/dd_table_share.h

@@ -24,6 +24,7 @@
 
 #include <sys/types.h>
 
+#include "field_types.h"
 #include "m_ctype.h"
 #include "my_inttypes.h"
 #include "my_sys.h"            // get_charset
@@ -33,7 +34,6 @@ class Field;
 class KEY_PART_INFO;
 class THD;
 struct TABLE_SHARE;
-enum enum_field_types : int;
 
 namespace dd {
 class Table;

Diff for: sql/item_create.h

@@ -32,6 +32,7 @@
 
 #include <cstddef>
 
+#include "field_types.h"
 #include "lex_string.h"
 #include "my_inttypes.h"         // uint
 #include "sql/parse_location.h"  // POS
@@ -47,7 +48,6 @@ class THD;
 struct Cast_type;
 struct CHARSET_INFO;
 struct udf_func;
-enum enum_field_types : int;
 enum class Json_on_response_type : uint16;
 
 /* For type casts */

Diff for: sql/sql_alter.h

@@ -31,6 +31,7 @@
 
 #include "lex_string.h"
 
+#include "field_types.h"
 #include "my_io.h"
 #include "my_sqlcommand.h"
 #include "mysql/components/services/bits/psi_bits.h"
@@ -54,8 +55,6 @@ class String;
 class THD;
 struct TABLE_LIST;
 
-enum enum_field_types : int;
-
 /**
   Class representing DROP COLUMN, DROP KEY, DROP FOREIGN KEY, DROP CHECK
   CONSTRAINT and DROP CONSTRAINT clauses in ALTER TABLE statement.

Diff for: sql/sql_show.h

@@ -26,6 +26,7 @@
 #include <stddef.h>
 #include <sys/types.h>
 
+#include "field_types.h"
 #include "lex_string.h"
 #include "my_inttypes.h"
 #include "mysql/status_var.h"
@@ -51,7 +52,6 @@ struct TABLE_LIST;
 typedef enum enum_mysql_show_type SHOW_TYPE;
 enum enum_schema_tables : int;
 enum enum_var_type : int;
-enum enum_field_types : int;
 
 /** Characters shown for the command in 'show processlist'. */
 constexpr const size_t PROCESS_LIST_WIDTH{100};