fix: only clear logs when logs are turned on

src/class-tiny-logger.php

@@ -108,12 +108,19 @@ public function get_log_file_path() {
 	/**
 	 * Triggered when log_enabled is saved
 	 * - set the setting on the instance
-	 * - if turn on, clear the old logs
+	 * - will clear logs when turned on
+	 * 
+	 * Hooked to `pre_update_option_tinypng_logging_enabled` filter
+	 * 
+	 * @return bool true if enabled
 	 */
 	public static function on_save_log_enabled( $log_enabled, $old, $option ) {
 		$instance              = self::get_instance();
-		$instance->log_enabled = 'on' === $log_enabled;
-		if ( $instance->get_log_enabled() ) {
+		$was_enabled           = 'on' === $old;
+		$is_now_enabled        = 'on' === $log_enabled;
+		$instance->log_enabled = $is_now_enabled;
+
+		if ( ! $was_enabled && $is_now_enabled ) {
 			self::clear_logs();
 		}
 

test/unit/TinyLoggerTest.php

@@ -113,4 +113,42 @@ public function test_removes_full_log_and_creates_new()
 
 		assertTrue(filesize($logger->get_log_file_path()) < 1048576, 'log file rotated and less than 1MB');
 	}
+
+	public function test_clears_logs_when_turned_on() {		
+		$log_dir_path = 'wp-content/uploads/tiny-compress-logs';
+		vfsStream::newDirectory($log_dir_path)->at($this->vfs);
+		$log_dir = $this->vfs->getChild($log_dir_path);
+		vfsStream::newFile('tiny-compress.log')
+			->withContent('Some existing log content')
+			->at($log_dir);
+
+		$logger = Tiny_Logger::get_instance();
+		$log_path = $logger->get_log_file_path();
+
+		assertTrue(file_exists($log_path), 'log file should exist');
+
+		Tiny_Logger::on_save_log_enabled( 'on', 'off', null );
+
+		assertFalse( file_exists($log_path), 'log file should be deleted after turning on logging' );
+	}
+
+	public function test_keeps_logs_when_unchanged() {		
+		$log_dir_path = 'wp-content/uploads/tiny-compress-logs';
+		vfsStream::newDirectory($log_dir_path)->at($this->vfs);
+		$log_dir = $this->vfs->getChild($log_dir_path);
+		vfsStream::newFile('tiny-compress.log')
+			->withContent('Some existing log content')
+			->at($log_dir);
+
+		$logger = Tiny_Logger::get_instance();
+		$log_path = $logger->get_log_file_path();
+
+		assertTrue(file_exists($log_path), 'log file should exist');
+
+		Tiny_Logger::on_save_log_enabled( 'on', 'on', null );
+
+		assertTrue( file_exists($log_path), 'log file should still exist when settings remain unchanged' );
+
+		unlink($log_path);
+	}
 }