Merge branch 'MDL-74886-400' of https://github.com/lameze/moodle into…

… MOODLE_400_STABLE

lib/adminlib.php

@@ -4010,7 +4010,9 @@ public function write_setting($data) {
             return '';
         }
 
-        $seconds = (int)($data['v']*$data['u']);
+        $unit = (int)$data['u'];
+        $value = (int)$data['v'];
+        $seconds = $value * $unit;
 
         // Validate the new setting.
         $error = $this->validate_setting($seconds);

lib/tests/admintree_test.php

@@ -357,6 +357,17 @@ public function test_preventexecpath() {
         $this->assertSame('', get_config('abc_cde', 'execpath'));
     }
 
+    /**
+     * Test setting an empty duration displays the correct validation message.
+     */
+    public function test_emptydurationvalue() {
+        $this->resetAfterTest();
+        $adminsetting = new admin_setting_configduration('abc_cde/duration', 'some desc', '', '');
+
+        // A value that isn't a number is treated as a zero, so we expect to see no error message.
+        $this->assertEmpty($adminsetting->write_setting(['u' => '3600', 'v' => 'abc']));
+    }
+
     /**
      * Test setting for blocked hosts
      *