Use connection() instead of $connection

adminer/call.inc.php

@@ -26,7 +26,7 @@ if (!$error && $_POST) {
 				$val = "''";
 			}
 			if (isset($out[$key])) {
-				$connection->query("SET @" . idf_escape($field["field"]) . " = $val");
+				connection()->query("SET @" . idf_escape($field["field"]) . " = $val");
 			}
 		}
 		$call[] = (isset($out[$key]) ? "@" . idf_escape($field["field"]) : $val);
@@ -34,8 +34,8 @@ if (!$error && $_POST) {
 
 	$query = (isset($_GET["callf"]) ? "SELECT" : "CALL") . " " . table($PROCEDURE) . "(" . implode(", ", $call) . ")";
 	$start = microtime(true);
-	$result = $connection->multi_query($query);
-	$affected = $connection->affected_rows; // getting warnings overwrites this
+	$result = connection()->multi_query($query);
+	$affected = connection()->affected_rows; // getting warnings overwrites this
 	echo adminer()->selectQuery($query, $start, !$result);
 
 	if (!$result) {
@@ -47,7 +47,7 @@ if (!$error && $_POST) {
 		}
 
 		do {
-			$result = $connection->store_result();
+			$result = connection()->store_result();
 			if (is_object($result)) {
 				print_select_result($result, $connection2);
 			} else {
@@ -55,10 +55,10 @@ if (!$error && $_POST) {
 					. " <span class='time'>" . @date("H:i:s") . "</span>\n" // @ - time zone may be not set
 				;
 			}
-		} while ($connection->next_result());
+		} while (connection()->next_result());
 
 		if ($out) {
-			print_select_result($connection->query("SELECT " . implode(", ", $out)));
+			print_select_result(connection()->query("SELECT " . implode(", ", $out)));
 		}
 	}
 }

adminer/drivers/mssql.inc.php

@@ -170,8 +170,7 @@ if (isset($_GET["mssql"])) {
 		}
 
 		function last_id($result) {
-			global $connection;
-			return $connection->lastInsertId();
+			return connection()->lastInsertId();
 		}
 
 		function explain($connection, $query) {
@@ -323,10 +322,9 @@ if (isset($_GET["mssql"])) {
 	}
 
 	function count_tables($databases) {
-		global $connection;
 		$return = array();
 		foreach ($databases as $db) {
-			$connection->select_db($db);
+			connection()->select_db($db);
 			$return[$db] = get_val("SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES");
 		}
 		return $return;
@@ -428,8 +426,7 @@ WHERE OBJECT_NAME(i.object_id) = " . q($table), $connection2) as $row
 	}
 
 	function error() {
-		global $connection;
-		return nl_br(h(preg_replace('~^(\[[^]]*])+~m', '', $connection->error)));
+		return nl_br(h(preg_replace('~^(\[[^]]*])+~m', '', connection()->error)));
 	}
 
 	function create_database($db, $collation) {

adminer/drivers/mysql.inc.php

@@ -8,6 +8,7 @@ if (!defined('Adminer\DRIVER')) {
 	// MySQLi supports everything, MySQL doesn't support multiple result sets, PDO_MySQL doesn't support orgtable
 	if (extension_loaded("mysqli") && $_GET["ext"] != "pdo") {
 		class Db extends \MySQLi {
+			/** @var Db|string */ static $instance = '';
 			public string $extension = "MySQLi", $flavor = '';
 
 			function __construct() {
@@ -487,8 +488,7 @@ if (!defined('Adminer\DRIVER')) {
 	* @return Field[]
 	*/
 	function fields(string $table): array {
-		global $connection;
-		$maria = ($connection->flavor == 'maria');
+		$maria = (connection()->flavor == 'maria');
 		$return = array();
 		foreach (get_rows("SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = " . q($table) . " ORDER BY ORDINAL_POSITION") as $row) {
 			$field = $row["COLUMN_NAME"];
@@ -616,8 +616,7 @@ if (!defined('Adminer\DRIVER')) {
 
 	/** Get escaped error message */
 	function error(): string {
-		global $connection;
-		return h(preg_replace('~^You have an error.*syntax to use~U', "Syntax error", $connection->error));
+		return h(preg_replace('~^You have an error.*syntax to use~U', "Syntax error", connection()->error));
 	}
 
 	/** Create database
@@ -685,14 +684,13 @@ if (!defined('Adminer\DRIVER')) {
 	* @return Result|bool
 	*/
 	function alter_table(string $table, string $name, array $fields, array $foreign, ?string $comment, string $engine, string $collation, string $auto_increment, string $partitioning) {
-		global $connection;
 		$alter = array();
 		foreach ($fields as $field) {
 			if ($field[1]) {
 				$default = $field[1][3];
 				if (preg_match('~ GENERATED~', $default)) {
 					// swap default and null
-					$field[1][3] = ($connection->flavor == 'maria' ? "" : $field[1][2]); // MariaDB doesn't support NULL on virtual columns
+					$field[1][3] = (connection()->flavor == 'maria' ? "" : $field[1][2]); // MariaDB doesn't support NULL on virtual columns
 					$field[1][2] = $default;
 				}
 				$alter[] = ($table != "" ? ($field[0] != "" ? "CHANGE " . idf_escape($field[0]) : "ADD") : " ") . " " . implode($field[1]) . ($table != "" ? $field[2] : "");
@@ -762,7 +760,6 @@ if (!defined('Adminer\DRIVER')) {
 	* @param list<string> $views
 	*/
 	function move_tables(array $tables, array $views, string $target): bool {
-		global $connection;
 		$rename = array();
 		foreach ($tables as $table) {
 			$rename[] = table($table) . " TO " . idf_escape($target) . "." . table($table);
@@ -772,7 +769,7 @@ if (!defined('Adminer\DRIVER')) {
 			foreach ($views as $table) {
 				$definitions[table($table)] = view($table);
 			}
-			$connection->select_db($target);
+			connection()->select_db($target);
 			$db = idf_escape(DB);
 			foreach ($definitions as $name => $view) {
 				if (!queries("CREATE VIEW $name AS " . str_replace(" $db.", " ", $view["select"])) || !queries("DROP VIEW $db.$name")) {

adminer/drivers/oracle.inc.php

@@ -154,7 +154,6 @@ if (isset($_GET["oracle"])) {
 		}
 
 		function insertUpdate(string $table, array $rows, array $primary) {
-			global $connection;
 			foreach ($rows as $set) {
 				$update = array();
 				$where = array();
@@ -165,7 +164,7 @@ if (isset($_GET["oracle"])) {
 					}
 				}
 				if (
-					!(($where && queries("UPDATE " . table($table) . " SET " . implode(", ", $update) . " WHERE " . implode(" AND ", $where)) && $connection->affected_rows)
+					!(($where && queries("UPDATE " . table($table) . " SET " . implode(", ", $update) . " WHERE " . implode(" AND ", $where)) && connection()->affected_rows)
 					|| queries("INSERT INTO " . table($table) . " (" . implode(", ", array_keys($set)) . ") VALUES (" . implode(", ", $set) . ")"))
 				) {
 					return false;
@@ -224,9 +223,8 @@ ORDER BY 1"
 	}
 
 	function get_current_db() {
-		global $connection;
-		$db = $connection->_current_db ?: DB;
-		unset($connection->_current_db);
+		$db = connection()->_current_db ?: DB;
+		unset(connection()->_current_db);
 		return $db;
 	}
 
@@ -347,8 +345,7 @@ ORDER BY ac.constraint_type, aic.column_position", $connection2) as $row
 	}
 
 	function error() {
-		global $connection;
-		return h($connection->error); //! highlight sqltext from offset
+		return h(connection()->error); //! highlight sqltext from offset
 	}
 
 	function explain($connection, $query) {
@@ -474,9 +471,8 @@ AND c_src.TABLE_NAME = " . q($table);
 	}
 
 	function set_schema($scheme, $connection2 = null) {
-		global $connection;
 		if (!$connection2) {
-			$connection2 = $connection;
+			$connection2 = connection();
 		}
 		return $connection2->query("ALTER SESSION SET CURRENT_SCHEMA = " . idf_escape($scheme));
 	}

adminer/drivers/pgsql.inc.php

@@ -218,7 +218,6 @@ if (isset($_GET["pgsql"])) {
 		}
 
 		function insertUpdate(string $table, array $rows, array $primary) {
-			global $connection;
 			foreach ($rows as $set) {
 				$update = array();
 				$where = array();
@@ -229,7 +228,7 @@ if (isset($_GET["pgsql"])) {
 					}
 				}
 				if (
-					!(($where && queries("UPDATE " . table($table) . " SET " . implode(", ", $update) . " WHERE " . implode(" AND ", $where)) && $connection->affected_rows)
+					!(($where && queries("UPDATE " . table($table) . " SET " . implode(", ", $update) . " WHERE " . implode(" AND ", $where)) && connection()->affected_rows)
 					|| queries("INSERT INTO " . table($table) . " (" . implode(", ", array_keys($set)) . ") VALUES (" . implode(", ", $set) . ")"))
 				) {
 					return false;
@@ -354,10 +353,9 @@ ORDER BY 1";
 	}
 
 	function count_tables($databases) {
-		global $connection;
 		$return = array();
 		foreach ($databases as $db) {
-			if ($connection->select_db($db)) {
+			if (connection()->select_db($db)) {
 				$return[$db] = count(tables_list());
 			}
 		}
@@ -453,9 +451,8 @@ ORDER BY a.attnum") as $row
 	}
 
 	function indexes($table, $connection2 = null) {
-		global $connection;
 		if (!is_object($connection2)) {
-			$connection2 = $connection;
+			$connection2 = connection();
 		}
 		$return = array();
 		$table_oid = get_val("SELECT oid FROM pg_class WHERE relnamespace = (SELECT oid FROM pg_namespace WHERE nspname = current_schema()) AND relname = " . q($table), 0, $connection2);
@@ -521,8 +518,7 @@ ORDER BY conkey, conname") as $row
 	}
 
 	function error() {
-		global $connection;
-		$return = h($connection->error);
+		$return = h(connection()->error);
 		if (preg_match('~^(.*\n)?([^\n]*)\n( *)\^(\n.*)?$~s', $return, $match)) {
 			$return = $match[1] . preg_replace('~((?:[^&]|&[^;]*;){' . strlen($match[3]) . '})(.*)~', '\1<b>\2</b>', $match[2]) . $match[4];
 		}
@@ -534,14 +530,12 @@ ORDER BY conkey, conname") as $row
 	}
 
 	function drop_databases($databases) {
-		global $connection;
-		$connection->close();
+		connection()->close();
 		return apply_queries("DROP DATABASE", $databases, 'Adminer\idf_escape');
 	}
 
 	function rename_database($name, $collation) {
-		global $connection;
-		$connection->close();
+		connection()->close();
 		return queries("ALTER DATABASE " . idf_escape(DB) . " RENAME TO " . idf_escape($name));
 	}
 
@@ -792,9 +786,8 @@ AND typelem = 0"
 	}
 
 	function set_schema($schema, $connection2 = null) {
-		global $connection;
 		if (!$connection2) {
-			$connection2 = $connection;
+			$connection2 = connection();
 		}
 		$return = $connection2->query("SET search_path TO " . idf_escape($schema));
 		driver()->setUserTypes(types()); //! get types from current_schemas('t')
@@ -929,9 +922,8 @@ AND typelem = 0"
 	}
 
 	function support($feature) {
-		global $connection;
 		return preg_match('~^(check|database|table|columns|sql|indexes|descidx|comment|view|' . (min_version(9.3) ? 'materializedview|' : '') . 'scheme|' . (min_version(11) ? 'procedure|' : '') . 'routine|sequence|trigger|type|variables|drop_col'
-			. ($connection->flavor == 'cockroach' ? '' : '|processlist') // https://github.com/cockroachdb/cockroach/issues/24745
+			. (connection()->flavor == 'cockroach' ? '' : '|processlist') // https://github.com/cockroachdb/cockroach/issues/24745
 			. '|kill|dump)$~', $feature)
 		;
 	}

adminer/drivers/sqlite.inc.php

@@ -270,9 +270,8 @@ if (isset($_GET["sqlite"])) {
 	}
 
 	function indexes($table, $connection2 = null) {
-		global $connection;
 		if (!is_object($connection2)) {
-			$connection2 = $connection;
+			$connection2 = connection();
 		}
 		$return = array();
 		$sql = get_val("SELECT sql FROM sqlite_master WHERE type = 'table' AND name = " . q($table), 0, $connection2);
@@ -342,25 +341,22 @@ if (isset($_GET["sqlite"])) {
 	}
 
 	function error() {
-		global $connection;
-		return h($connection->error);
+		return h(connection()->error);
 	}
 
 	function check_sqlite_name($name) {
 		// avoid creating PHP files on unsecured servers
-		global $connection;
 		$extensions = "db|sdb|sqlite";
 		if (!preg_match("~^[^\\0]*\\.($extensions)\$~", $name)) {
-			$connection->error = lang('Please use one of the extensions %s.', str_replace("|", ", ", $extensions));
+			connection()->error = lang('Please use one of the extensions %s.', str_replace("|", ", ", $extensions));
 			return false;
 		}
 		return true;
 	}
 
 	function create_database($db, $collation) {
-		global $connection;
 		if (file_exists($db)) {
-			$connection->error = lang('File exists.');
+			connection()->error = lang('File exists.');
 			return false;
 		}
 		if (!check_sqlite_name($db)) {
@@ -370,7 +366,7 @@ if (isset($_GET["sqlite"])) {
 			$link = new Db();
 			$link->attach($db, '', '');
 		} catch (\Exception $ex) {
-			$connection->error = $ex->getMessage();
+			connection()->error = $ex->getMessage();
 			return false;
 		}
 		$link->query('PRAGMA encoding = "UTF-8"');
@@ -380,11 +376,10 @@ if (isset($_GET["sqlite"])) {
 	}
 
 	function drop_databases($databases) {
-		global $connection;
-		$connection->attach(":memory:", '', ''); // to unlock file, doesn't work in PDO on Windows
+		connection()->attach(":memory:", '', ''); // to unlock file, doesn't work in PDO on Windows
 		foreach ($databases as $db) {
 			if (!@unlink($db)) {
-				$connection->error = lang('File exists.');
+				connection()->error = lang('File exists.');
 				return false;
 			}
 		}
@@ -392,12 +387,11 @@ if (isset($_GET["sqlite"])) {
 	}
 
 	function rename_database($name, $collation) {
-		global $connection;
 		if (!check_sqlite_name($name)) {
 			return false;
 		}
-		$connection->attach(":memory:", '', '');
-		$connection->error = lang('File exists.');
+		connection()->attach(":memory:", '', '');
+		connection()->error = lang('File exists.');
 		return @rename(DB, $name);
 	}
 
@@ -406,7 +400,6 @@ if (isset($_GET["sqlite"])) {
 	}
 
 	function alter_table($table, $name, $fields, $foreign, $comment, $engine, $collation, $auto_increment, $partitioning) {
-		global $connection;
 		$use_all_fields = ($table == "" || $foreign);
 		foreach ($fields as $field) {
 			if ($field[0] != "" || !$field[1] || $field[2]) {
@@ -439,7 +432,7 @@ if (isset($_GET["sqlite"])) {
 		if ($auto_increment) {
 			queries("BEGIN");
 			queries("UPDATE sqlite_sequence SET seq = $auto_increment WHERE name = " . q($name)); // ignores error
-			if (!$connection->affected_rows) {
+			if (!connection()->affected_rows) {
 				queries("INSERT INTO sqlite_sequence (name, seq) VALUES (" . q($name) . ", $auto_increment)");
 			}
 			queries("COMMIT");
@@ -533,7 +526,7 @@ if (isset($_GET["sqlite"])) {
 		}
 		$temp_name = ($table == $name ? "adminer_$name" : $name);
 		if (!queries("CREATE TABLE " . table($temp_name) . " (\n" . implode(",\n", $changes) . "\n)")) {
-			// implicit ROLLBACK to not overwrite $connection->error
+			// implicit ROLLBACK to not overwrite connection()->error
 			return false;
 		}
 		if ($table != "") {

adminer/dump.inc.php

@@ -16,7 +16,7 @@ if ($_POST && !$error) {
 	$is_sql = preg_match('~sql~', $_POST["format"]);
 
 	if ($is_sql) {
-		echo "-- Adminer " . VERSION . " " . get_driver(DRIVER) . " " . str_replace("\n", " ", $connection->server_info) . " dump\n\n";
+		echo "-- Adminer " . VERSION . " " . get_driver(DRIVER) . " " . str_replace("\n", " ", connection()->server_info) . " dump\n\n";
 		if (JUSH == "sql") {
 			echo "SET NAMES utf8;
 SET time_zone = '+00:00';
@@ -24,8 +24,8 @@ SET foreign_key_checks = 0;
 " . ($_POST["data_style"] ? "SET sql_mode = 'NO_AUTO_VALUE_ON_ZERO';
 " : "") . "
 ";
-			$connection->query("SET time_zone = '+00:00'");
-			$connection->query("SET sql_mode = ''");
+			connection()->query("SET time_zone = '+00:00'");
+			connection()->query("SET sql_mode = ''");
 		}
 	}
 
@@ -40,7 +40,7 @@ SET foreign_key_checks = 0;
 
 	foreach ((array) $databases as $db) {
 		adminer()->dumpDatabase($db);
-		if ($connection->select_db($db)) {
+		if (connection()->select_db($db)) {
 			if ($is_sql && preg_match('~CREATE~', $style) && ($create = get_val("SHOW CREATE DATABASE " . idf_escape($db), 1))) {
 				set_utf8mb4($create);
 				if ($style == "DROP+CREATE") {

adminer/foreign.inc.php

@@ -58,7 +58,7 @@ if ($_POST) {
 <?php
 $source = array_keys(fields($TABLE)); //! no text and blob
 if ($row["db"] != "") {
-	$connection->select_db($row["db"]);
+	connection()->select_db($row["db"]);
 }
 if ($row["ns"] != "") {
 	$orig_schema = get_schema();

adminer/include/adminer.inc.php

@@ -521,7 +521,6 @@ class Adminer {
 	* @return list<string> expressions to join by AND
 	*/
 	function selectSearchProcess(array $fields, array $indexes): array {
-		global $connection;
 		$return = array();
 		foreach ($indexes as $i => $index) {
 			if ($index["type"] == "FULLTEXT" && $_GET["fulltext"][$i] != "") {
@@ -793,7 +792,6 @@ class Adminer {
 	* @return void prints data
 	*/
 	function dumpData(string $table, string $style, string $query): void {
-		global $connection;
 		if ($style) {
 			$max_packet = (JUSH == "sqlite" ? 0 : 1048576); // default, minimum is 1024
 			$fields = array();
@@ -813,7 +811,7 @@ class Adminer {
 					}
 				}
 			}
-			$result = $connection->query($query, 1); // 1 - MYSQLI_USE_RESULT //! enum and set as numbers
+			$result = connection()->query($query, 1); // 1 - MYSQLI_USE_RESULT //! enum and set as numbers
 			if ($result) {
 				$insert = "";
 				$buffer = "";
@@ -872,7 +870,7 @@ class Adminer {
 					echo $buffer . $suffix;
 				}
 			} elseif ($_POST["format"] == "sql") {
-				echo "-- " . str_replace("\n", " ", $connection->error) . "\n";
+				echo "-- " . str_replace("\n", " ", connection()->error) . "\n";
 			}
 			if ($identity_insert) {
 				echo "SET IDENTITY_INSERT " . table($table) . " OFF;\n";
@@ -938,7 +936,6 @@ class Adminer {
 	* @param string $missing can be "auth" if there is no database connection, "db" if there is no database selected, "ns" with invalid schema
 	*/
 	function navigation(string $missing): void {
-		global $connection;
 		echo "<h1>" . adminer()->name() . " <span class='version'>" . VERSION;
 		$new_version = $_COOKIE["adminer_version"];
 		echo " <a href='https://www.adminer.org/#download'" . target_blank() . " id='version'>" . (version_compare(VERSION, $new_version) < 0 ? h($new_version) : "") . "</a>";
@@ -966,7 +963,7 @@ class Adminer {
 		} else {
 			$tables = array();
 			if ($_GET["ns"] !== "" && !$missing && DB != "") {
-				$connection->select_db(DB);
+				connection()->select_db(DB);
 				$tables = table_status('', true);
 			}
 			adminer()->syntaxHighlighting($tables);
@@ -998,7 +995,6 @@ class Adminer {
 	* @param TableStatus[] $tables
 	*/
 	function syntaxHighlighting(array $tables): void {
-		global $connection;
 		// this is matched by compile.php
 		echo script_src("../externals/jush/modules/jush.js");
 		echo script_src("../externals/jush/modules/jush-textarea.js");
@@ -1019,14 +1015,13 @@ class Adminer {
 			}
 			echo "</script>\n";
 		}
-		echo script("syntaxHighlighting('" . (is_object($connection) ? preg_replace('~^(\d\.?\d).*~s', '\1', $connection->server_info) : "") . "'"
-			. ($connection->flavor == 'maria' ? ", 'maria'" : ($connection->flavor == 'cockroach' ? ", 'cockroach'" : "")) . ");"
+		echo script("syntaxHighlighting('" . (is_object(connection()) ? preg_replace('~^(\d\.?\d).*~s', '\1', connection()->server_info) : "") . "'"
+			. (connection()->flavor == 'maria' ? ", 'maria'" : (connection()->flavor == 'cockroach' ? ", 'cockroach'" : "")) . ");"
 		);
 	}
 
 	/** Print databases list in menu */
 	function databasesPrint(string $missing): void {
-		global $connection;
 		$databases = adminer()->databases();
 		if (DB && $databases && !in_array(DB, $databases)) {
 			array_unshift($databases, DB);
@@ -1040,7 +1035,7 @@ class Adminer {
 		);
 		echo "<input type='submit' value='" . lang('Use') . "'" . ($databases ? " class='hidden'" : "") . ">\n";
 		if (support("scheme")) {
-			if ($missing != "db" && DB != "" && $connection->select_db(DB)) {
+			if ($missing != "db" && DB != "" && connection()->select_db(DB)) {
 				echo "<br><span>" . lang('Schema') . ":</span> " . html_select("ns", array("" => "") + adminer()->schemas(), $_GET["ns"]) . $db_events;
 				if ($_GET["ns"] != "") {
 					set_schema($_GET["ns"]);

adminer/include/auth.inc.php

@@ -1,8 +1,6 @@
 <?php
 namespace Adminer;
 
-$connection = '';
-
 $permanent = array();
 if ($_COOKIE["adminer_permanent"]) {
 	foreach (explode(" ", $_COOKIE["adminer_permanent"]) as $val) {
@@ -175,18 +173,18 @@ if (isset($_GET["username"]) && is_string(get_password())) {
 		auth_error(lang('Connecting to privileged ports is not allowed.'), $permanent);
 	}
 	check_invalid_login($permanent);
-	$connection = connect(adminer()->credentials());
-	if (is_object($connection)) {
-		Driver::$instance = new Driver($connection);
-		if ($connection->flavor) {
+	Db::$instance = connect(adminer()->credentials());
+	if (is_object(Db::$instance)) {
+		Driver::$instance = new Driver(Db::$instance);
+		if (Db::$instance->flavor) {
 			save_settings(array("vendor-" . DRIVER . "-" . SERVER => get_driver(DRIVER)));
 		}
 	}
 }
 
 $login = null;
-if (!is_object($connection) || ($login = adminer()->login($_GET["username"], get_password())) !== true) {
-	$error = (is_string($connection) ? nl_br(h($connection)) : (is_string($login) ? $login : lang('Invalid credentials.')));
+if (!is_object(connection()) || ($login = adminer()->login($_GET["username"], get_password())) !== true) {
+	$error = (is_string(connection()) ? nl_br(h(connection())) : (is_string($login) ? $login : lang('Invalid credentials.')));
 	auth_error(
 		$error . (preg_match('~^ | $~', get_password()) ? '<br>' . lang('There is a space in the input password which might be the cause.') : ''),
 		$permanent

adminer/include/bootstrap.inc.php

@@ -39,7 +39,7 @@ if ($_GET["script"] == "version") {
 	exit;
 }
 
-global $connection, $translations; // allows including Adminer inside a function
+global $translations; // allows including Adminer inside a function
 
 if (!$_SERVER["REQUEST_URI"]) { // IIS 5 compatibility
 	$_SERVER["REQUEST_URI"] = $_SERVER["ORIG_PATH_INFO"];

adminer/include/connect.inc.php

@@ -10,7 +10,7 @@ if (isset($_GET["import"])) {
 
 if (
 	!(DB != ""
-		? $connection->select_db(DB)
+		? connection()->select_db(DB)
 		: isset($_GET["sql"]) || isset($_GET["dump"]) || isset($_GET["database"]) || isset($_GET["processlist"]) || isset($_GET["privileges"]) || isset($_GET["user"]) || isset($_GET["variables"])
 			|| $_GET["script"] == "connect" || $_GET["script"] == "kill"
 	)
@@ -42,7 +42,7 @@ if (
 				echo "<a href='" . h(ME) . "$key='>$val</a>\n";
 			}
 		}
-		echo "<p>" . lang('%s version: %s through PHP extension %s', get_driver(DRIVER), "<b>" . h($connection->server_info) . "</b>", "<b>$connection->extension</b>") . "\n";
+		echo "<p>" . lang('%s version: %s through PHP extension %s', get_driver(DRIVER), "<b>" . h(connection()->server_info) . "</b>", "<b>" . connection()->extension . "</b>") . "\n";
 		echo "<p>" . lang('Logged as: %s', "<b>" . h(logged_user()) . "</b>") . "\n";
 		if (isset(adminer()->plugins) && is_array(adminer()->plugins)) {
 			echo "<p>" . lang('Loaded plugins') . ":\n<ul>\n";

adminer/include/db.inc.php

@@ -4,6 +4,8 @@ namespace Adminer;
 // this could be interface when "Db extends \mysqli" can have compatible type declarations (PHP 7)
 // interfaces can include properties only since PHP 8.4
 abstract class SqlDb {
+	/** @var Db|string */ static $instance = ''; // string means error
+
 	public string $extension; // extension name
 	public string $flavor = ''; // different vendor with the same API, e.g. MariaDB; usually stays empty
 	public string $server_info; // server version

adminer/include/editing.inc.php

@@ -206,9 +206,8 @@ function edit_type(string $key, array $field, array $collations, array $foreign_
 * @return array{partition_by:string, partition:string, partitions:string, partition_names:list<string>, partition_values:list<string>}
 */
 function get_partitions_info(string $table): array {
-	global $connection;
 	$from = "FROM information_schema.PARTITIONS WHERE TABLE_SCHEMA = " . q(DB) . " AND TABLE_NAME = " . q($table);
-	$result = $connection->query("SELECT PARTITION_METHOD, PARTITION_EXPRESSION, PARTITION_ORDINAL_POSITION $from ORDER BY PARTITION_ORDINAL_POSITION DESC LIMIT 1");
+	$result = connection()->query("SELECT PARTITION_METHOD, PARTITION_EXPRESSION, PARTITION_ORDINAL_POSITION $from ORDER BY PARTITION_ORDINAL_POSITION DESC LIMIT 1");
 	$return = array();
 	list($return["partition_by"], $return["partition"], $return["partitions"]) = $result->fetch_row();
 	$partitions = get_key_vals("SELECT PARTITION_NAME, PARTITION_DESCRIPTION $from AND PARTITION_NAME != '' ORDER BY PARTITION_ORDINAL_POSITION");
@@ -543,17 +542,16 @@ function ini_bytes(string $ini): int {
 * @return string HTML code
 */
 function doc_link(array $paths, string $text = "<sup>?</sup>"): string {
-	global $connection;
-	$server_info = $connection->server_info;
+	$server_info = connection()->server_info;
 	$version = preg_replace('~^(\d\.?\d).*~s', '\1', $server_info); // two most significant digits
 	$urls = array(
 		'sql' => "https://dev.mysql.com/doc/refman/$version/en/",
 		'sqlite' => "https://www.sqlite.org/",
-		'pgsql' => "https://www.postgresql.org/docs/" . ($connection->flavor == 'cockroach' ? "current" : $version) . "/",
+		'pgsql' => "https://www.postgresql.org/docs/" . (connection()->flavor == 'cockroach' ? "current" : $version) . "/",
 		'mssql' => "https://learn.microsoft.com/en-us/sql/",
 		'oracle' => "https://www.oracle.com/pls/topic/lookup?ctx=db" . preg_replace('~^.* (\d+)\.(\d+)\.\d+\.\d+\.\d+.*~s', '\1\2', $server_info) . "&id=",
 	);
-	if ($connection->flavor == 'maria') {
+	if (connection()->flavor == 'maria') {
 		$urls['sql'] = "https://mariadb.com/kb/en/";
 		$paths['sql'] = (isset($paths['mariadb']) ? $paths['mariadb'] : str_replace(".html", "/", $paths['sql']));
 	}
@@ -564,8 +562,7 @@ function doc_link(array $paths, string $text = "<sup>?</sup>"): string {
 * @return string formatted
 */
 function db_size(string $db): string {
-	global $connection;
-	if (!$connection->select_db($db)) {
+	if (!connection()->select_db($db)) {
 		return "?";
 	}
 	$return = 0;
@@ -577,10 +574,9 @@ function db_size(string $db): string {
 
 /** Print SET NAMES if utf8mb4 might be needed */
 function set_utf8mb4(string $create): void {
-	global $connection;
 	static $set = false;
 	if (!$set && preg_match('~\butf8mb4~i', $create)) { // possible false positive
 		$set = true;
-		echo "SET NAMES " . charset($connection) . ";\n\n";
+		echo "SET NAMES " . charset(connection()) . ";\n\n";
 	}
 }

adminer/include/functions.inc.php

@@ -3,11 +3,12 @@ namespace Adminer;
 
 // This file is used both in Adminer and Adminer Editor.
 
-/** Get database connection */
-function connection(): Db {
-	// can be used in customization, $connection is minified
-	global $connection;
-	return $connection;
+/** Get database connection
+* @return Db|string string means error
+*/
+function connection() {
+	// can be used in customization, Db::$instance is minified
+	return Db::$instance;
 }
 
 /** Get Adminer object
@@ -33,10 +34,9 @@ function idf_unescape(string $idf): string {
 	return str_replace($last . $last, $last, substr($idf, 1, -1));
 }
 
-/** Shortcut for $connection->quote($string) */
+/** Shortcut for connection()->quote($string) */
 function q(string $string): string {
-	global $connection;
-	return $connection->quote($string);
+	return connection()->quote($string);
 }
 
 /** Escape string to use inside '' */
@@ -96,12 +96,11 @@ function bracket_escape(string $idf, bool $back = false): string {
 /** Check if connection has at least the given version
 * @param string|float $version required version
 * @param string|float $maria_db required MariaDB version
-* @param Db $connection2 defaults to $connection
+* @param Db $connection2 defaults to connection()
 */
 function min_version($version, $maria_db = "", Db $connection2 = null): bool {
-	global $connection;
 	if (!$connection2) {
-		$connection2 = $connection;
+		$connection2 = connection();
 	}
 	$server_info = $connection2->server_info;
 	if ($maria_db && preg_match('~([\d.]+)-MariaDB~', $server_info, $match)) {
@@ -157,8 +156,7 @@ function get_password() {
 * @return string|false false if error
 */
 function get_val(string $query, int $field = 0, ?Db $conn = null) {
-	global $connection;
-	$conn = (is_object($conn) ? $conn : $connection);
+	$conn = (is_object($conn) ? $conn : connection());
 	$result = $conn->query($query);
 	if (!is_object($result)) {
 		return false;
@@ -172,9 +170,8 @@ function get_val(string $query, int $field = 0, ?Db $conn = null) {
 * @return list<string>
 */
 function get_vals(string $query, $column = 0): array {
-	global $connection;
 	$return = array();
-	$result = $connection->query($query);
+	$result = connection()->query($query);
 	if (is_object($result)) {
 		while ($row = $result->fetch_row()) {
 			$return[] = $row[$column];
@@ -187,9 +184,8 @@ function get_vals(string $query, $column = 0): array {
 * @return string[]
 */
 function get_key_vals(string $query, Db $connection2 = null, bool $set_keys = true): array {
-	global $connection;
 	if (!is_object($connection2)) {
-		$connection2 = $connection;
+		$connection2 = connection();
 	}
 	$return = array();
 	$result = $connection2->query($query);
@@ -209,8 +205,7 @@ function get_key_vals(string $query, Db $connection2 = null, bool $set_keys = tr
 * @return list<string[]> of associative arrays
 */
 function get_rows(string $query, Db $connection2 = null, string $error = "<p class='error'>"): array {
-	global $connection;
-	$conn = (is_object($connection2) ? $connection2 : $connection);
+	$conn = (is_object($connection2) ? $connection2 : connection());
 	$return = array();
 	$result = $conn->query($query);
 	if (is_object($result)) { // can return true
@@ -256,7 +251,6 @@ function escape_key(string $key): string {
 * @param Field[] $fields
 */
 function where(array $where, array $fields = array()): string {
-	global $connection;
 	$return = array();
 	foreach ((array) $where["where"] as $key => $val) {
 		$key = bracket_escape($key, true); // true - back
@@ -270,7 +264,7 @@ function where(array $where, array $fields = array()): string {
 				: " = " . unconvert_field($field, q($val)))))
 		; //! enum and set
 		if (JUSH == "sql" && preg_match('~char|text~', $field_type) && preg_match("~[^ -@]~", $val)) { // not just [a-z] to catch non-ASCII characters
-			$return[] = "$column = " . q($val) . " COLLATE " . charset($connection) . "_bin";
+			$return[] = "$column = " . q($val) . " COLLATE " . charset(connection()) . "_bin";
 		}
 	}
 	foreach ((array) $where["null"] as $key) {
@@ -430,10 +424,9 @@ function redirect(?string $location, string $message = null): void {
 * @param bool $redirect
 */
 function query_redirect(string $query, ?string $location, string $message, $redirect = true, bool $execute = true, bool $failed = false, string $time = ""): bool {
-	global $connection;
 	if ($execute) {
 		$start = microtime(true);
-		$failed = !$connection->query($query);
+		$failed = !connection()->query($query);
 		$time = format_time($start);
 	}
 	$sql = ($query ? adminer()->messageQuery($query, $time, $failed) : "");
@@ -457,12 +450,11 @@ class Queries {
 * @return Result|bool
 */
 function queries(string $query) {
-	global $connection;
 	if (!Queries::$start) {
 		Queries::$start = microtime(true);
 	}
 	Queries::$queries[] = (preg_match('~;$~', $query) ? "DELIMITER ;;\n$query;\nDELIMITER " : $query) . ";";
-	return $connection->query($query);
+	return connection()->query($query);
 }
 
 /** Apply command to all array items

adminer/include/html.inc.php

@@ -331,13 +331,12 @@ function process_input(array $field) {
 * @uses $_POST["tables"]
 */
 function search_tables(): void {
-	global $connection;
 	$_GET["where"][0]["val"] = $_POST["query"];
 	$sep = "<ul>\n";
 	foreach (table_status('', true) as $table => $table_status) {
 		$name = adminer()->tableName($table_status);
 		if (isset($table_status["Engine"]) && $name != "" && (!$_POST["tables"] || in_array($table, $_POST["tables"]))) {
-			$result = $connection->query("SELECT" . limit("1 FROM " . table($table), " WHERE " . implode(" AND ", adminer()->selectSearchProcess(fields($table), array())), 1));
+			$result = connection()->query("SELECT" . limit("1 FROM " . table($table), " WHERE " . implode(" AND ", adminer()->selectSearchProcess(fields($table), array())), 1));
 			if (!$result || $result->fetch_row()) {
 				$print = "<a href='" . h(ME . "select=" . urlencode($table) . "&where[0][op]=" . urlencode($_GET["where"][0]["op"]) . "&where[0][val]=" . urlencode($_GET["where"][0]["val"])) . "'>$name</a>";
 				echo "$sep<li>" . ($result ? $print : "<p class='error'>$print: " . error()) . "\n";

adminer/privileges.inc.php

@@ -5,11 +5,11 @@ page_header(lang('Privileges'));
 
 echo '<p class="links"><a href="' . h(ME) . 'user=">' . lang('Create user') . "</a>";
 
-$result = $connection->query("SELECT User, Host FROM mysql." . (DB == "" ? "user" : "db WHERE " . q(DB) . " LIKE Db") . " ORDER BY Host, User");
+$result = connection()->query("SELECT User, Host FROM mysql." . (DB == "" ? "user" : "db WHERE " . q(DB) . " LIKE Db") . " ORDER BY Host, User");
 $grant = $result;
 if (!$result) {
 	// list logged user, information_schema.USER_PRIVILEGES lists just the current user too
-	$result = $connection->query("SELECT SUBSTRING_INDEX(CURRENT_USER, '@', 1) AS User, SUBSTRING_INDEX(CURRENT_USER, '@', -1) AS Host");
+	$result = connection()->query("SELECT SUBSTRING_INDEX(CURRENT_USER, '@', 1) AS User, SUBSTRING_INDEX(CURRENT_USER, '@', -1) AS Host");
 }
 
 echo "<form action=''><p>\n";

adminer/script.inc.php

@@ -36,7 +36,7 @@ if ($_GET["script"] == "db") {
 	json_row("");
 
 } elseif ($_GET["script"] == "kill") {
-	$connection->query("KILL " . number($_POST["kill"]));
+	connection()->query("KILL " . number($_POST["kill"]));
 
 } else { // connect
 	foreach (count_tables(adminer()->databases()) as $db => $val) {

adminer/select.inc.php

@@ -127,7 +127,7 @@ if ($_POST && !$error) {
 							: driver()->update($TABLE, $set, $where_check)
 						)
 					);
-					$affected = $connection->affected_rows;
+					$affected = connection()->affected_rows;
 					if (is_object($result)) { // PostgreSQL with RETURNING fills num_rows
 						$affected += $result->num_rows;
 					}
@@ -145,7 +145,7 @@ if ($_POST && !$error) {
 						if (!$result) {
 							break;
 						}
-						$affected += $connection->affected_rows;
+						$affected += connection()->affected_rows;
 					}
 				}
 			}
@@ -186,7 +186,7 @@ if ($_POST && !$error) {
 					if (!$result) {
 						break;
 					}
-					$affected += $connection->affected_rows;
+					$affected += connection()->affected_rows;
 				}
 				queries_redirect(remove_from_uri(), lang('%d item(s) have been affected.', $affected), $result);
 			}

adminer/sql.inc.php

@@ -126,16 +126,16 @@ if (!$error && $_POST) {
 							}
 							$start = microtime(true);
 							//! don't allow changing of character_set_results, convert encoding of displayed query
-							if ($connection->multi_query($q) && is_object($connection2) && preg_match("~^$space*+USE\\b~i", $q)) {
+							if (connection()->multi_query($q) && is_object($connection2) && preg_match("~^$space*+USE\\b~i", $q)) {
 								$connection2->query($q);
 							}
 
 							do {
-								$result = $connection->store_result();
+								$result = connection()->store_result();
 
-								if ($connection->error) {
+								if (connection()->error) {
 									echo ($_POST["only_errors"] ? $print : "");
-									echo "<p class='error'>" . lang('Error in query') . ($connection->errno ? " ($connection->errno)" : "") . ": " . error() . "\n";
+									echo "<p class='error'>" . lang('Error in query') . (connection()->errno ? " (" . connection()->errno . ")" : "") . ": " . error() . "\n";
 									$errors[] = " <a href='#sql-$commands'>$commands</a>";
 									if ($_POST["error_stops"]) {
 										break 2;
@@ -145,7 +145,7 @@ if (!$error && $_POST) {
 									$time = " <span class='time'>(" . format_time($start) . ")</span>"
 										. (strlen($q) < 1000 ? " <a href='" . h(ME) . "sql=" . urlencode(trim($q)) . "'>" . lang('Edit') . "</a>" : "") // 1000 - maximum length of encoded URL in IE is 2083 characters
 									;
-									$affected = $connection->affected_rows; // getting warnings overwrites this
+									$affected = connection()->affected_rows; // getting warnings overwrites this
 									$warnings = ($_POST["only_errors"] ? "" : driver()->warnings());
 									$warnings_id = "warnings-$commands";
 									if ($warnings) {
@@ -182,7 +182,7 @@ if (!$error && $_POST) {
 											stop_session();
 										}
 										if (!$_POST["only_errors"]) {
-											echo "<p class='message' title='" . h($connection->info) . "'>" . lang('Query executed OK, %d row(s) affected.', $affected) . "$time\n";
+											echo "<p class='message' title='" . h(connection()->info) . "'>" . lang('Query executed OK, %d row(s) affected.', $affected) . "$time\n";
 										}
 									}
 									echo ($warnings ? "<div id='$warnings_id' class='hidden'>\n$warnings</div>\n" : "");
@@ -194,7 +194,7 @@ if (!$error && $_POST) {
 								}
 
 								$start = microtime(true);
-							} while ($connection->next_result());
+							} while (connection()->next_result());
 						}
 
 						$query = substr($query, $offset);

adminer/user.inc.php

@@ -29,7 +29,7 @@ if ($_POST) {
 $grants = array();
 $old_pass = "";
 
-if (isset($_GET["host"]) && ($result = $connection->query("SHOW GRANTS FOR " . q($USER) . "@" . q($_GET["host"])))) { //! use information_schema for MySQL 5 - column names in column privileges are not escaped
+if (isset($_GET["host"]) && ($result = connection()->query("SHOW GRANTS FOR " . q($USER) . "@" . q($_GET["host"])))) { //! use information_schema for MySQL 5 - column names in column privileges are not escaped
 	while ($row = $result->fetch_row()) {
 		if (preg_match('~GRANT (.*) ON (.*) TO ~', $row[0], $match) && preg_match_all('~ *([^(,]*[^ ,(])( *\([^)]+\))?~', $match[1], $matches, PREG_SET_ORDER)) { //! escape the part between ON and TO
 			foreach ($matches as $val) {
@@ -113,7 +113,7 @@ if ($_POST && !$error) {
 
 		if ($created) {
 			// delete new user in case of an error
-			$connection->query("DROP USER $new_user");
+			connection()->query("DROP USER $new_user");
 		}
 	}
 }