This PR was merged into the 5.0-dev branch.Discussion----------[Validator] Fix tests| Q             | A| ------------- | ---| Branch?       | master <!-- see below -->| Bug fix?      | yes| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets | relates to#32265   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | N/AFixes the following tests currently failing on master, as well as a bug where a null code was printed:```diff1) Symfony\Component\Validator\Tests\ConstraintViolationListTest::testToStringFailed asserting that two strings are equal.--- Expected+++ Actual@@ @@ 'Root:\n-    Error 1\n+    Error 1 (code )\n Root.foo.bar:\n-    Error 2\n+    Error 2 (code )\n Root[baz]:\n-    Error 3\n+    Error 3 (code )\n foo.bar:\n-    Error 4\n+    Error 4 (code )\n [baz]:\n-    Error 5\n+    Error 5 (code )\n2) Symfony\Component\Validator\Tests\ConstraintViolationTest::testToStringHandlesArraysFailed asserting that two strings are identical.--- Expected+++ Actual@@ @@ 'Root.property.path:-    Array'+    Array (code )'3) Symfony\Component\Validator\Tests\ConstraintViolationTest::testToStringHandlesArrayRootsFailed asserting that two strings are identical.--- Expected+++ Actual@@ @@ 'Array.some_value:-    42 cannot be used here'+    42 cannot be used here (code )'4) Symfony\Component\Validator\Tests\ConstraintViolationTest::testToStringOmitsEmptyCodesFailed asserting that two strings are identical.--- Expected+++ Actual@@ @@ 'Array.some_value:-    42 cannot be used here'+    42 cannot be used here (code )'5) Symfony\Component\Validator\Tests\ConstraintViolationTest::testNonStringCodeFailed asserting that '42' is identical to 42.6) Symfony\Component\Validator\Tests\Violation\ConstraintViolationBuilderTest::testNonStringCodeFailed asserting that '42' is identical to 42.```Commits-------22c58f5 [Validator] Fix tests

…o false & make it optional (ogizanagi)This PR was merged into the 5.0-dev branch.Discussion----------[Validator] Change Length::$allowEmptyString default to false & make it optional| Q             | A| ------------- | ---| Branch?       | master <!-- see below -->| Bug fix?      | no| New feature?  | yes <!-- please update src/**/CHANGELOG.md files -->| BC breaks?    | yes     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | should pass after#32372    <!-- please add some, will be required by reviewers -->| Fixed tickets |#31528   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | ~TODO: change default value and mention it's optional~ Done. Thx@javiereguiluzCommits-------26b804e [Validator] Change Length::$allowEmptyString default to false & make it optional