From 01aee79df01edadab5dd4047ecc3500cb5988cc0 Mon Sep 17 00:00:00 2001
From: Leon Stringer <leon.stringer@ntlworld.com>
Date: Thu, 12 Nov 2020 14:44:11 +0000
Subject: [PATCH] MDL-70181 database: Quote database object names

Table names and database name now enclosed in backticks.
admin/cli/mysql_collation.php failed if $CFG->prefix was blank with
MySQL 8.0 because table 'groups' conflicted with a new reserved word.

Note that this quotes both mysql_collation.php and mysql_compressed_rows.php
but only the former was mal-functioning.

The case of mysql_compressed_rows.php is a little bit special because
not all tables are processed, only those having big rows. And the groups
table is not one of them. In any case, better add the quotes there for
any future case.

Also, when testing this patch https://tracker.moodle.org/browse/MDL-71512
was discovered and will need to be fixed to make core 100% compliant
with MySQL 8.0 and MariaDB 10.6 and up.
---
 admin/cli/mysql_collation.php       | 16 ++++++++--------
 admin/cli/mysql_compressed_rows.php |  4 ++--
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/admin/cli/mysql_collation.php b/admin/cli/mysql_collation.php
index ba8a49ef7cc..591f81e9a5d 100644
--- a/admin/cli/mysql_collation.php
+++ b/admin/cli/mysql_collation.php
@@ -119,7 +119,7 @@ if (!empty($options['collation'])) {
     if ($dbcollation->value !== $collation || $dbcharset->value !== $charset) {
         // Try to convert the DB.
         echo "Converting database to '$collation' for $CFG->wwwroot:\n";
-        $sql = "ALTER DATABASE $CFG->dbname DEFAULT CHARACTER SET $charset DEFAULT COLLATE = $collation";
+        $sql = "ALTER DATABASE `$CFG->dbname` DEFAULT CHARACTER SET $charset DEFAULT COLLATE = $collation";
         try {
             $DB->change_database_structure($sql);
         } catch (exception $e) {
@@ -146,7 +146,7 @@ if (!empty($options['collation'])) {
 
         } else {
             try {
-                $DB->change_database_structure("ALTER TABLE $table->name CONVERT TO CHARACTER SET $charset COLLATE $collation");
+                $DB->change_database_structure("ALTER TABLE `$table->name` CONVERT TO CHARACTER SET $charset COLLATE $collation");
                 echo "CONVERTED\n";
                 $converted++;
             } catch (ddl_exception $e) {
@@ -163,7 +163,7 @@ if (!empty($options['collation'])) {
             }
         }
 
-        $sql = "SHOW FULL COLUMNS FROM $table->name WHERE collation IS NOT NULL";
+        $sql = "SHOW FULL COLUMNS FROM `$table->name` WHERE collation IS NOT NULL";
         $rs2 = $DB->get_recordset_sql($sql);
         foreach ($rs2 as $column) {
             $column = (object)array_change_key_case((array)$column, CASE_LOWER);
@@ -181,7 +181,7 @@ if (!empty($options['collation'])) {
                 $notnull = ($column->null === 'NO') ? 'NOT NULL' : 'NULL';
                 $default = (!is_null($column->default) and $column->default !== '') ? "DEFAULT '$column->default'" : '';
                 // primary, unique and inc are not supported for texts
-                $sql = "ALTER TABLE $table->name
+                $sql = "ALTER TABLE `$table->name`
                         MODIFY COLUMN $column->field $column->type
                         CHARACTER SET $charset
                         COLLATE $collation $notnull $default";
@@ -192,11 +192,11 @@ if (!empty($options['collation'])) {
                 $default = !is_null($column->default) ? "DEFAULT '$column->default'" : '';
 
                 if ($rowformat != '') {
-                    $sql = "ALTER TABLE $table->name $rowformat";
+                    $sql = "ALTER TABLE `$table->name` $rowformat";
                     $DB->change_database_structure($sql);
                 }
 
-                $sql = "ALTER TABLE $table->name
+                $sql = "ALTER TABLE `$table->name`
                         MODIFY COLUMN $column->field $column->type
                         CHARACTER SET $charset
                         COLLATE $collation $notnull $default";
@@ -315,8 +315,8 @@ function mysql_set_row_format($tablename, $charset, $collation, $engine) {
         if ($rs->row_format == 'Compact' || $rs->row_format == 'Redundant') {
             $rowformat = $DB->get_row_format_sql($engine, $collation);
             // Try to convert to compressed format and then try updating the collation again.
-            $DB->change_database_structure("ALTER TABLE $tablename $rowformat");
-            $DB->change_database_structure("ALTER TABLE $tablename CONVERT TO CHARACTER SET $charset COLLATE $collation");
+            $DB->change_database_structure("ALTER TABLE `$tablename` $rowformat");
+            $DB->change_database_structure("ALTER TABLE `$tablename` CONVERT TO CHARACTER SET $charset COLLATE $collation");
         } else {
             // Row format may not be the problem. Can not diagnose problem. Send fail reply.
             return false;
diff --git a/admin/cli/mysql_compressed_rows.php b/admin/cli/mysql_compressed_rows.php
index e90060cdd8d..d9d421105cc 100644
--- a/admin/cli/mysql_compressed_rows.php
+++ b/admin/cli/mysql_compressed_rows.php
@@ -158,7 +158,7 @@ if (!empty($options['info'])) {
     }
 
     foreach ($fixtables as $table) {
-        $DB->change_database_structure("ALTER TABLE {$prefix}$table ROW_FORMAT=Compressed");
+        $DB->change_database_structure("ALTER TABLE `{$prefix}$table` ROW_FORMAT=Compressed");
         echo str_pad($prefix . $table, 32, ' ', STR_PAD_RIGHT) . " ... Compressed\n";
     }
 
@@ -189,7 +189,7 @@ if (!empty($options['info'])) {
     echo "SET GLOBAL innodb_file_per_table=1;\n";
     echo "SET GLOBAL innodb_file_format=Barracuda;\n";
     foreach ($fixtables as $table) {
-        echo "ALTER TABLE {$prefix}$table ROW_FORMAT=Compressed;\n";
+        echo "ALTER TABLE `{$prefix}$table` ROW_FORMAT=Compressed;\n";
     }
     echo "\n";
     exit(0);