allow negative duration via internal API (#3573)

src/Validator/Constraints/Duration.php

@@ -21,11 +21,12 @@ class Duration extends Regex
     {
         $patterns = [
             // decimal times (can be separated by comma or dot, depending on the locale)
-            '[0-9]{1,}',
-            '[0-9]{1,}[,.]{1}[0-9]{1,}',
+            // negative times -? are allowed, because plugins could allow negative times
+            '-?[0-9]{1,}',
+            '-?[0-9]{1,}[,.]{1}[0-9]{1,}',
             // ASP.NET style time spans - https://momentjs.com/docs/#/durations/
-            '[0-9]{1,}:[0-9]{1,}:[0-9]{1,}',
-            '[0-9]{1,}:[0-9]{1,}',
+            '-?[0-9]{1,}:[0-9]{1,}:[0-9]{1,}',
+            '-?[0-9]{1,}:[0-9]{1,}',
             // https://en.wikipedia.org/wiki/ISO_8601#Time_intervals
             '[0-9]{1,}[hHmMsS]{1}',
             '[0-9]{1,}[hH]{1}[0-9]{1,}[mM]{1}',

src/Validator/Constraints/TimesheetBasicValidator.php

@@ -132,9 +132,6 @@ final class TimesheetBasicValidator extends ConstraintValidator
                 ->addViolation();
         }
 
-        $pathStart = 'begin';
-        $pathEnd = 'end';
-
         $projectBegin = $project->getStart();
         $projectEnd = $project->getEnd();
 
@@ -142,10 +139,13 @@ final class TimesheetBasicValidator extends ConstraintValidator
             return;
         }
 
+        $pathStart = 'begin';
+        $pathEnd = 'end';
+
         $timesheetStart = $timesheet->getBegin();
         $timesheetEnd = $timesheet->getEnd();
 
-        if (null !== $timesheetStart && $pathStart !== null) {
+        if (null !== $timesheetStart) {
             if (null !== $projectBegin && $timesheetStart->getTimestamp() < $projectBegin->getTimestamp()) {
                 $context->buildViolation('The project has not started at that time.')
                     ->atPath($pathStart)
@@ -161,7 +161,7 @@ final class TimesheetBasicValidator extends ConstraintValidator
             }
         }
 
-        if (null !== $timesheetEnd && $pathEnd !== null) {
+        if (null !== $timesheetEnd) {
             if (null !== $projectEnd && $timesheetEnd->getTimestamp() > $projectEnd->getTimestamp()) {
                 $context->buildViolation('The project is finished at that time.')
                     ->atPath($pathEnd)