Handle reading empty file in ReversedFileReader

fix #10766

src/Util/ReversedFileReader.php

@@ -95,6 +95,9 @@ class ReversedFileReader implements \Iterator
 			if ($this->pos == 0) {
 				return array_pop($buffer);
 			}
+			if (is_null($buffer)) {
+				return null;
+			}
 			if (count($buffer) > 1) {
 				return array_pop($buffer);
 			}

tests/src/Model/Log/ParsedLogIteratorTest.php

@@ -145,4 +145,16 @@ class ParsedLogIteratorTest extends TestCase
 		$pls = iterator_to_array($this->pli, false);
 		self::assertCount(0, $pls);
 	}
+
+	public function testEmptyLogFile()
+	{
+		$logfile = dirname(__DIR__) . '/../../datasets/log/empty.friendica.log.txt';
+
+		$reader    = new ReversedFileReader();
+		$pli = new ParsedLogIterator($reader);
+		$pli->open($logfile);
+
+		$pls = iterator_to_array($pli, false);
+		self::assertCount(0, $pls);
+	}
 }