Tag my_vsnprintf with __attribute__((format))

[Breaking]
Good news: GCC now checks your `my_snprintf` (direct) calls (`-Wformat` was on);
Bad news: The build process no longer lets your incorrect
formats/arguments sneak past (`-Werror` was also on).

As such, this commit also fixes all new `my_snprintf` `-Wformat` errors.
This commit does not update the ABI records – half a dozen
`include/mysql/plugin_*.h.pp` files are now missing the new `__attribute__`s.

client/mysql_upgrade.c

@@ -556,7 +556,7 @@ static void find_tool(char *tool_executable_name, const char *tool_name,
 
     len= (int)(last_fn_libchar - self_name);
 
-    my_snprintf(tool_executable_name, FN_REFLEN, "%.*b%c%s",
+    my_snprintf(tool_executable_name, FN_REFLEN, "%.*sB%c%s",
                 len, self_name, FN_LIBCHAR, tool_name);
   }
 

client/mysqlcheck.c

@@ -548,7 +548,7 @@ static int is_view(const char *table)
   int view;
   DBUG_ENTER("is_view");
 
-  my_snprintf(query, sizeof(query), "SHOW CREATE TABLE %`s", table);
+  my_snprintf(query, sizeof(query), "SHOW CREATE TABLE %sQ", table);
   if (mysql_query(sock, query))
   {
     fprintf(stderr, "Failed to %s\n", query);
@@ -797,7 +797,7 @@ static int fix_table_storage_name(const char *name)
 
   if (strncmp(name, "#mysql50#", 9))
     DBUG_RETURN(1);
-  my_snprintf(qbuf, sizeof(qbuf), "RENAME TABLE %`s TO %`s",
+  my_snprintf(qbuf, sizeof(qbuf), "RENAME TABLE %sQ TO %sQ",
               name, name + 9);
 
   rc= run_query(qbuf, 1);
@@ -814,7 +814,7 @@ static int fix_database_storage_name(const char *name)
 
   if (strncmp(name, "#mysql50#", 9))
     DBUG_RETURN(1);
-  my_snprintf(qbuf, sizeof(qbuf), "ALTER DATABASE %`s UPGRADE DATA DIRECTORY "
+  my_snprintf(qbuf, sizeof(qbuf), "ALTER DATABASE %sQ UPGRADE DATA DIRECTORY "
               "NAME", name);
   rc= run_query(qbuf, 1);
   if (!opt_silent)
@@ -1023,7 +1023,7 @@ static void insert_table_name(DYNAMIC_ARRAY *arr, char *in, size_t dblen)
 {
   char buf[NAME_LEN*2+2];
   in[dblen]= 0;
-  my_snprintf(buf, sizeof(buf), "%`s.%`s", in, in + dblen + 1);
+  my_snprintf(buf, sizeof(buf), "%sQ.%sQ", in, in + dblen + 1);
   insert_dynamic(arr, (uchar*) buf);
 }
 

include/mysql/service_my_snprintf.h

@@ -94,8 +94,10 @@ extern "C" {
 #endif
 
 extern struct my_snprintf_service_st {
-  size_t (*my_snprintf_type)(char*, size_t, const char*, ...);
-  size_t (*my_vsnprintf_type)(char *, size_t, const char*, va_list);
+  size_t (*my_snprintf_type)(char*, size_t, const char*, ...)
+    __attribute__((format(printf, 3, 4)));
+  size_t (*my_vsnprintf_type)(char *, size_t, const char*, va_list)
+    __attribute__((format(printf, 3, 0)));
 } *my_snprintf_service;
 
 #ifdef MYSQL_DYNAMIC_PLUGIN
@@ -105,8 +107,10 @@ extern struct my_snprintf_service_st {
 
 #else
 
-size_t my_snprintf(char* to, size_t n, const char* fmt, ...);
-size_t my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap);
+size_t my_snprintf(char* to, size_t n, const char* fmt, ...)
+  __attribute__((format(printf, 3, 4)));
+size_t my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
+  __attribute__((format(printf, 3, 0)));
 
 #endif
 

plugin/server_audit/server_audit.c

@@ -1415,7 +1415,7 @@ static size_t log_header(char *message, size_t message_len,
   if (output_type == OUTPUT_SYSLOG)
     return my_snprintf(message, message_len,
         "%.*s,%.*s,%.*s,%d,%lld,%s",
-        (unsigned int) serverhost_len, serverhost,
+        (int) serverhost_len, serverhost,
         username_len, username,
         host_len, host,
         connection_id, query_id, operation);
@@ -1425,7 +1425,7 @@ static size_t log_header(char *message, size_t message_len,
       "%04d%02d%02d %02d:%02d:%02d,%.*s,%.*s,%.*s,%d,%lld,%s",
       tm_time.tm_year+1900, tm_time.tm_mon+1, tm_time.tm_mday,
       tm_time.tm_hour, tm_time.tm_min, tm_time.tm_sec,
-      serverhost_len, serverhost,
+      (int) serverhost_len, serverhost,
       username_len, username,
       host_len, host,
       connection_id, query_id, operation);
@@ -1494,7 +1494,7 @@ static int log_connection_event(const struct mysql_event_connection *event,
                     event->ip, event->ip_length,
                     event->thread_id, 0, type);
   csize+= my_snprintf(message+csize, sizeof(message) - 1 - csize,
-    ",%.*s,,%d", event->database.length, event->database.str, event->status);
+    ",%.*s,,%d", (int) event->database.length, event->database.str, event->status);
   message[csize]= '\n';
   return write_log(message, csize + 1, 1);
 }
@@ -1926,9 +1926,9 @@ static int log_table(const struct connection_info *cn,
                     event->host, SAFE_STRLEN_UI(event->host),
                     event->ip, SAFE_STRLEN_UI(event->ip),
                     event->thread_id, cn->query_id, type);
-  csize+= my_snprintf(message+csize, sizeof(message) - 1 - csize,
-            ",%.*s,%.*s,",event->database.length, event->database.str,
-                          event->table.length, event->table.str);
+  csize+= my_snprintf(message+csize, sizeof(message) - 1 - csize, ",%.*s,%.*s,",
+                     (int) event->database.length, event->database.str,
+                     (int) event->table.length, event->table.str);
   message[csize]= '\n';
   return write_log(message, csize + 1, 1);
 }
@@ -1949,10 +1949,11 @@ static int log_rename(const struct connection_info *cn,
                     event->ip, SAFE_STRLEN_UI(event->ip),
                     event->thread_id, cn->query_id, "RENAME");
   csize+= my_snprintf(message+csize, sizeof(message) - 1 - csize,
-            ",%.*s,%.*s|%.*s.%.*s,",event->database.length, event->database.str,
-                         event->table.length, event->table.str,
-                         event->new_database.length, event->new_database.str,
-                         event->new_table.length, event->new_table.str);
+                      ",%.*s,%.*s|%.*s.%.*s,",
+                      (int) event->database.length, event->database.str,
+                      (int) event->table.length, event->table.str,
+                      (int) event->new_database.length, event->new_database.str,
+                      (int) event->new_table.length, event->new_table.str);
   message[csize]= '\n';
   return write_log(message, csize + 1, 1);
 }
@@ -3127,4 +3128,3 @@ void __attribute__ ((constructor)) audit_plugin_so_init(void)
   return;
 #endif
 }
-

sql/item_cmpfunc.cc

@@ -6212,8 +6212,8 @@ bool Regexp_processor_pcre::compile(String *pattern, bool send_error)
       int lmsg= pcre2_get_error_message(pcreErrorNumber,
                                         (PCRE2_UCHAR8 *)buff, sizeof(buff));
       if (lmsg >= 0)
-        my_snprintf(buff+lmsg, sizeof(buff)-lmsg,
-                    " at offset %d", pcreErrorOffset);
+        snprintf(buff+lmsg, sizeof(buff)-lmsg,
+                 " at offset %zu", pcreErrorOffset);
       my_error(ER_REGEXP_ERROR, MYF(0), buff);
     }
     return true;
@@ -8013,4 +8013,3 @@ Item *Item_equal::multiple_equality_transformer(THD *thd, uchar *arg)
     break;
   }
 }
-

sql/log_event_client.cc

@@ -3284,7 +3284,7 @@ static void get_type_name(uint type, unsigned char** meta_ptr,
 {
   switch (type) {
   case MYSQL_TYPE_LONG:
-    my_snprintf(typestr, typestr_length, "%s", "INT");
+    my_snprintf(typestr, typestr_length, "INT");
     break;
   case MYSQL_TYPE_TINY:
     my_snprintf(typestr, typestr_length, "TINYINT");
@@ -3354,20 +3354,21 @@ static void get_type_name(uint type, unsigned char** meta_ptr,
     break;
   case MYSQL_TYPE_BLOB:
     {
-      bool is_text= (cs && cs->number != my_charset_bin.number);
-      const char *names[5][2] = {
-        {"INVALID_BLOB(%d)", "INVALID_TEXT(%d)"},
-        {"TINYBLOB", "TINYTEXT"},
-        {"BLOB", "TEXT"},
-        {"MEDIUMBLOB", "MEDIUMTEXT"},
-        {"LONGBLOB", "LONGTEXT"}
+      const char *type_name=
+        (cs && cs->number != my_charset_bin.number) ? "TEXT" : "BLOB";
+      const char *names[5]= {
+        NullS,
+        "TINY",
+        "",
+        "MEDIUM",
+        "LONG"
       };
       unsigned char size= **meta_ptr;
 
       if (size == 0 || size > 4)
-        my_snprintf(typestr, typestr_length, names[0][is_text], size);
+        my_snprintf(typestr, typestr_length, "INVALID_%s(%d)", type_name, size);
       else
-        my_snprintf(typestr, typestr_length, names[**meta_ptr][is_text]);
+        my_snprintf(typestr, typestr_length, "%s%s", names[size], type_name);
 
       (*meta_ptr)++;
     }
@@ -3404,7 +3405,7 @@ static void get_type_name(uint type, unsigned char** meta_ptr,
         "MULTILINESTRING", "MULTIPOLYGON", "GEOMETRYCOLLECTION"
       };
       if (geometry_type < 8)
-        my_snprintf(typestr, typestr_length, names[geometry_type]);
+        my_snprintf(typestr, typestr_length, "%s", names[geometry_type]);
       else
         my_snprintf(typestr, typestr_length, "INVALID_GEOMETRY_TYPE(%u)",
                     geometry_type);

sql/sql_admin.cc

@@ -711,7 +711,7 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
             protocol->store(&table_name, system_charset_info);
             protocol->store(operator_name, system_charset_info);
             protocol->store(&error_clex_str, system_charset_info);
-            length= my_snprintf(buff, sizeof(buff),
+            length= my_snprintf(buff, sizeof(buff), "%s",
                                 ER_THD(thd, ER_PARTITION_DOES_NOT_EXIST));
             protocol->store(buff, length, system_charset_info);
             if(protocol->write())

sql/sql_db.cc

@@ -1237,7 +1237,7 @@ mysql_rm_db_internal(THD *thd, const Lex_ident_db &db, bool if_exists,
       if (ha_table_exists(thd, &tbl->db, &tbl->table_name))
         continue;
 
-      tbl_name_len= my_snprintf(quoted_name, sizeof(quoted_name), "%`s",
+      tbl_name_len= my_snprintf(quoted_name, sizeof(quoted_name), "%sQ",
                                 tbl->table_name.str);
       tbl_name_len++;                           /* +1 for the comma */
       if (query_pos + tbl_name_len + 1 >= query_end)

sql/sql_type.h

@@ -722,7 +722,7 @@ class Sec6
   size_t to_string(char *to, size_t nbytes) const
   {
     return m_usec ?
-      my_snprintf(to, nbytes, "%s%llu.%06lu",
+      my_snprintf(to, nbytes, "%s%llu.%06u",
                   m_neg ? "-" : "", m_sec, (uint) m_usec) :
       my_snprintf(to, nbytes, "%s%llu", m_neg ? "-" : "", m_sec);
   }

sql/table.cc

@@ -4078,27 +4078,29 @@ static void print_long_unique_table(TABLE *table)
           " fields->offset,field->null_bit, field->null_pos and key_info ... \n"
           "\nPrinting  Table  keyinfo\n");
   str.append(buff, strlen(buff));
-  my_snprintf(buff, sizeof(buff), "\ntable->s->reclength %d\n"
-          "table->s->fields %d\n",
+  my_snprintf(buff, sizeof(buff), "\ntable->s->reclength %lu\n"
+          "table->s->fields %u\n",
           table->s->reclength, table->s->fields);
   str.append(buff, strlen(buff));
   for (uint i= 0; i < table->s->keys; i++)
   {
     key_info_table= table->key_info + i;
     key_info_share= table->s->key_info + i;
-    my_snprintf(buff, sizeof(buff), "\ntable->key_info[%d] user_defined_key_parts = %d\n"
-                                    "table->key_info[%d] algorithm == HA_KEY_ALG_LONG_HASH = %d\n"
-                                    "table->key_info[%d] flags & HA_NOSAME = %d\n",
-                                   i, key_info_table->user_defined_key_parts,
-                                   i, key_info_table->algorithm == HA_KEY_ALG_LONG_HASH,
-                                   i, key_info_table->flags & HA_NOSAME);
+    my_snprintf(buff, sizeof(buff),
+                "\ntable->key_info[%d] user_defined_key_parts = %d\n"
+                "table->key_info[%d] algorithm == HA_KEY_ALG_LONG_HASH = %d\n"
+                "table->key_info[%d] flags & HA_NOSAME = %lu\n",
+                i, key_info_table->user_defined_key_parts,
+                i, key_info_table->algorithm == HA_KEY_ALG_LONG_HASH,
+                i, key_info_table->flags & HA_NOSAME);
     str.append(buff, strlen(buff));
-    my_snprintf(buff, sizeof(buff), "\ntable->s->key_info[%d] user_defined_key_parts = %d\n"
-                                    "table->s->key_info[%d] algorithm == HA_KEY_ALG_LONG_HASH = %d\n"
-                                    "table->s->key_info[%d] flags & HA_NOSAME = %d\n",
-                                   i, key_info_share->user_defined_key_parts,
-                                   i, key_info_share->algorithm == HA_KEY_ALG_LONG_HASH,
-                                   i, key_info_share->flags & HA_NOSAME);
+    my_snprintf(buff, sizeof(buff),
+                "\ntable->s->key_info[%d] user_defined_key_parts = %d\n"
+                "table->s->key_info[%d] algorithm == HA_KEY_ALG_LONG_HASH = %d\n"
+                "table->s->key_info[%d] flags & HA_NOSAME = %lu\n",
+                i, key_info_share->user_defined_key_parts,
+                i, key_info_share->algorithm == HA_KEY_ALG_LONG_HASH,
+                i, key_info_share->flags & HA_NOSAME);
     str.append(buff, strlen(buff));
     key_part = key_info_table->key_part;
     my_snprintf(buff, sizeof(buff), "\nPrinting table->key_info[%d].key_part[0] info\n"
@@ -4131,9 +4133,9 @@ static void print_long_unique_table(TABLE *table)
   {
     field= table->field[i];
     my_snprintf(buff, sizeof(buff), "\ntable->field[%d]->field_name %s\n"
-            "table->field[%d]->offset = %d\n"
+            "table->field[%d]->offset = %ld\n"
             "table->field[%d]->field_length = %d\n"
-            "table->field[%d]->null_pos wrt to record 0 = %d\n"
+            "table->field[%d]->null_pos wrt to record 0 = %ld\n"
             "table->field[%d]->null_bit_pos = %d\n",
             i, field->field_name.str,
             i, field->ptr- table->record[0],

sql/wsrep_var.cc

@@ -966,7 +966,7 @@ bool wsrep_max_ws_size_update(sys_var *self, THD *thd, enum_var_type)
 {
   char max_ws_size_opt[128];
   my_snprintf(max_ws_size_opt, sizeof(max_ws_size_opt),
-              "repl.max_ws_size=%d", wsrep_max_ws_size);
+              "repl.max_ws_size=%lu", wsrep_max_ws_size);
   enum wsrep::provider::status ret= Wsrep_server_state::instance().provider().options(max_ws_size_opt);
   if (ret)
   {
@@ -1120,4 +1120,3 @@ bool wsrep_gtid_domain_id_update(sys_var* self, THD *thd, enum_var_type)
   wsrep_gtid_server.domain_id= wsrep_gtid_domain_id;
   return false;
 }
-

storage/example/ha_example.cc

@@ -1078,7 +1078,7 @@ static int show_func_example(MYSQL_THD thd, struct st_mysql_show_var *var,
   var->value= buf; // it's of SHOW_VAR_FUNC_BUFF_SIZE bytes
   my_snprintf(buf, SHOW_VAR_FUNC_BUFF_SIZE,
               "enum_var is %lu, ulong_var is %lu, int_var is %d, "
-              "double_var is %f, %.6b", // %b is a MariaDB/MySQL extension
+              "double_var is %f, %.6sB", // %sB is a MariaDB extension
               srv_enum_var, srv_ulong_var, THDVAR(thd, int_var),
               srv_double_var, "really");
   return 0;