Improve Database connection error messages (joomla#18587)

* Improve Database connection error messages

Before this PR you often get very unhelpful and hard to understand error messages

For example
Error displaying the error page: Application Instantiation Error: Could not connect to MySQL.

After this PR that error message would be
Error: Failed to start application: Could not connect to MySQL server.

You will see in the changes that before this PR we had identical error messages if mysql was not supported in php, mysql server details were wrong, mysql database could not be connected to.

After this PR they each have unique and more informative error messages. NOTE postgres and ms sql already had some of these more informative and accurate messages

* period

* Tweak pgsql message

* Tweak SQL Server message

libraries/joomla/database/driver/mysql.php

@@ -72,13 +72,13 @@ public function connect()
 		// Make sure the MySQL extension for PHP is installed and enabled.
 		if (!self::isSupported())
 		{
-			throw new JDatabaseExceptionUnsupported('Could not connect to MySQL.');
+			throw new JDatabaseExceptionUnsupported('Make sure the MySQL extension for PHP is installed and enabled.');
 		}
 
 		// Attempt to connect to the server.
 		if (!($this->connection = @ mysql_connect($this->options['host'], $this->options['user'], $this->options['password'], true)))
 		{
-			throw new JDatabaseExceptionConnecting('Could not connect to MySQL.');
+			throw new JDatabaseExceptionConnecting('Could not connect to MySQL server.');
 		}
 
 		// Set sql_mode to non_strict mode
@@ -366,7 +366,7 @@ public function select($database)
 
 		if (!mysql_select_db($database, $this->connection))
 		{
-			throw new JDatabaseExceptionConnecting('Could not connect to database');
+			throw new JDatabaseExceptionConnecting('Could not connect to MySQL database.');
 		}
 
 		return true;

libraries/joomla/database/driver/mysqli.php

@@ -160,7 +160,7 @@ public function connect()
 		// Make sure the MySQLi extension for PHP is installed and enabled.
 		if (!self::isSupported())
 		{
-			throw new JDatabaseExceptionUnsupported('The MySQL adapter mysqli is not available');
+			throw new JDatabaseExceptionUnsupported('The MySQLi extension for PHP is not installed or enabled.');
 		}
 
 		$this->connection = @mysqli_connect(
@@ -170,7 +170,7 @@ public function connect()
 		// Attempt to connect to the server.
 		if (!$this->connection)
 		{
-			throw new JDatabaseExceptionConnecting('Could not connect to MySQL.');
+			throw new JDatabaseExceptionConnecting('Could not connect to MySQL server.');
 		}
 
 		// Set sql_mode to non_strict mode
@@ -695,7 +695,7 @@ public function select($database)
 
 		if (!mysqli_select_db($this->connection, $database))
 		{
-			throw new JDatabaseExceptionConnecting('Could not connect to database.');
+			throw new JDatabaseExceptionConnecting('Could not connect to MySQL database.');
 		}
 
 		return true;

libraries/joomla/database/driver/postgresql.php

@@ -108,7 +108,7 @@ public function connect()
 		// Make sure the postgresql extension for PHP is installed and enabled.
 		if (!self::isSupported())
 		{
-			throw new JDatabaseExceptionUnsupported('PHP extension pg_connect is not available.');
+			throw new JDatabaseExceptionUnsupported('The pgsql extension for PHP is not installed or enabled.');
 		}
 
 		// Build the DSN for the connection.

libraries/joomla/database/driver/sqlsrv.php

@@ -118,7 +118,7 @@ public function connect()
 		// Make sure the SQLSRV extension for PHP is installed and enabled.
 		if (!self::isSupported())
 		{
-			throw new JDatabaseExceptionUnsupported('PHP extension sqlsrv_connect is not available.');
+			throw new JDatabaseExceptionUnsupported('The sqlsrv extension for PHP is not installed or enabled..');
 		}
 
 		// Attempt to connect to the server.
@@ -748,7 +748,7 @@ public function select($database)
 
 		if (!sqlsrv_query($this->connection, 'USE ' . $database, null, array('scrollable' => SQLSRV_CURSOR_STATIC)))
 		{
-			throw new JDatabaseExceptionConnecting('Could not connect to database');
+			throw new JDatabaseExceptionConnecting('Could not connect to SQL Server database.');
 		}
 
 		return true;

libraries/src/Exception/ExceptionHandler.php

@@ -146,7 +146,7 @@ public static function render($error)
 			header('HTTP/1.1 500 Internal Server Error');
 		}
 
-		$message = 'Error displaying the error page';
+		$message = 'Error';
 
 		if ($isException)
 		{

libraries/src/Factory.php

@@ -134,7 +134,7 @@ public static function getApplication($id = null, array $config = array(), $pref
 		{
 			if (!$id)
 			{
-				throw new \Exception('Application Instantiation Error', 500);
+				throw new \Exception('Failed to start application', 500);
 			}
 
 			self::$application = CMSApplication::getInstance($id);

tests/unit/suites/libraries/cms/error/JErrorPageTest.php

@@ -136,6 +136,6 @@ public function testEnsureTheRenderMethodCorrectlyHandlesNonExceptionClasses()
 		JErrorPage::render($object);
 		$output = ob_get_clean();
 
-		$this->assertEquals('Error displaying the error page', $output);
+		$this->assertEquals('Error', $output);
 	}
 }