Add proper Exceptions to class instead of false return on critical problems

src/DB/IO.php

@@ -340,6 +340,7 @@ class IO
 	// 4: convert numeric/floatN to float (CONVERT_NUMERIC)
 	// 8: convert bytea to string data (CONVERT_BYTEA)
 	/** @var int type settings as bit mask, 0 for off, anything >2 will aways set 1 too */
+	/** @phan-suppress-next-line PhanInvalidConstantExpression, PhanUndeclaredClassConstant */
 	private int $convert_type = Convert::off->value;
 	// FOR BELOW: (This should be private and only readable through some method)
 	// cursor array for cached readings
@@ -413,6 +414,7 @@ class IO
 	 * phpcs:ignore
 	 * @param array{db_name:string,db_user:string,db_pass:string,db_host:string,db_port:int,db_schema:string,db_encoding:string,db_type:string,db_ssl:string,db_convert_type?:string[]} $db_config DB configuration array
 	 * @param \CoreLibs\Logging\Logging $log Logging class
+	 * @throws \RuntimeException If no DB connection can be established on launch
 	 */
 	public function __construct(
 		array $db_config,
@@ -491,6 +493,7 @@ class IO
 		if (!$this->__connectToDB()) {
 			$this->__dbError(16);
 			$this->db_connection_closed = true;
+			throw new \RuntimeException('INIT: No DB Handler found / connect or reconnect failed', 16);
 		}
 	}
 
@@ -973,9 +976,9 @@ class IO
 	/**
 	 * write an error
 	 *
-	 * @param integer $error_id            Any Error ID, used in debug message string
+	 * @param integer $error_id           Any Error ID, used in debug message string
 	 * @param \PgSql\Result|false $cursor Optional cursor, passed on to preprocessor
-	 * @param string $msg                  optional message added to debug
+	 * @param string $msg                 optional message added to debug
 	 * @return void
 	 */
 	protected function __dbError(