MDEV-34713 Create mariadb_upgrade_info during mariadb-backup --copy-back

extra/mariabackup/backup_copy.cc

@@ -1926,6 +1926,30 @@ copy_back()
 
 	rocksdb_copy_back(ds_tmp);
 
+	/* MDEV-34713 Create mariadb_upgrade_info file to avoid unnecessary upgrade
+	prompts after restore */
+	if (ret) {
+		char upgrade_info_path[FN_REFLEN];
+		FILE *upgrade_info_file;
+
+		snprintf(upgrade_info_path, sizeof upgrade_info_path,
+			 "%s/mariadb_upgrade_info", mysql_data_home);
+
+		upgrade_info_file = fopen(upgrade_info_path, "w");
+		if (upgrade_info_file) {
+			if (fprintf(upgrade_info_file, "%s", MYSQL_SERVER_VERSION) < 0 ||
+			    fflush(upgrade_info_file) != 0) {
+				msg("Warning: Failed to write mariadb_upgrade_info");
+			} else {
+				msg("Created mariadb_upgrade_info with version %s",
+				    MYSQL_SERVER_VERSION);
+			}
+			fclose(upgrade_info_file);
+		} else {
+			msg("Warning: Failed to create mariadb_upgrade_info");
+		}
+	}
+
 cleanup:
 	if (it != NULL) {
 		datadir_iter_free(it);

mysql-test/suite/mariabackup/full_backup.result

@@ -16,6 +16,10 @@ INSERT INTO t VALUES(2);
 SELECT * FROM t;
 i
 1
+#
+# MDEV-34713 Check that mariadb_upgrade_info is created during copy-back
+#
+FOUND 1 /MariaDB/ in mariadb_upgrade_info
 DROP TABLE t;
 #
 #  MDEV-27121 mariabackup incompatible with disabled dedicated

mysql-test/suite/mariabackup/full_backup.test

@@ -31,6 +31,16 @@ exec $XTRABACKUP  --prepare --target-dir=$targetdir;
 --enable_result_log
 
 SELECT * FROM t;
+
+--echo #
+--echo # MDEV-34713 Check that mariadb_upgrade_info is created during copy-back
+--echo #
+let $_datadir= `SELECT @@datadir`;
+--file_exists $_datadir/mariadb_upgrade_info
+--let SEARCH_FILE=$_datadir/mariadb_upgrade_info
+--let SEARCH_PATTERN=MariaDB
+--source include/search_pattern_in_file.inc
+
 DROP TABLE t;
 rmdir $targetdir;