Sum up exception if multiple categories of required characters are missing.

src/Resources/contao/languages/de/exception.xlf

@@ -1,6 +1,7 @@
 <?xml version="1.0" ?>
 <xliff version="1.1">
-    <file datatype="php" original="src/Resources/contao/languages/de/exception.php" source-language="en" target-language="de">
+    <file datatype="php" original="src/Resources/contao/languages/de/exception.php" source-language="en"
+          target-language="de">
         <body>
             <trans-unit id="XPT.passwordValidation.maxLength">
                 <source>Please use a maximum of %s characters.</source>
@@ -30,6 +31,10 @@
                 <source>Please use at least %u characters out of the following: %s</source>
                 <target>Bitte verwenden Sie aus den folgenden Sonderzeichen mindestens %u Zeichen: %s</target>
             </trans-unit>
+            <trans-unit id="XPT.passwordValidation.required.summary">
+                <source>Please use at least %u uppercase letters, %u lowercase letters, %u numbers and %u special characters: %s</source>
+                <target>Bitte verwenden Sie mindestens %u Großbuchstaben, %u Kleinbuchstaben, %u Ziffern und %u Sonderzeichen: %s</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Resources/contao/languages/en/exception.xlf

@@ -23,6 +23,9 @@
             <trans-unit id="XPT.passwordValidation.required.other">
                 <source>Please use at least %u characters out of the following: %s</source>
             </trans-unit>
+            <trans-unit id="XPT.passwordValidation.required.summary">
+                <source>Please use at least %u uppercase letters, %u lowercase letters, %u numbers and %u special characters: %s</source>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Validation/Validator/RequiredCharacters.php

@@ -43,6 +43,7 @@ final class RequiredCharacters implements PasswordValidatorInterface
 
         $password = $context->getPassword()->getString();
 
+        $errors = [];
         foreach ($require as $category => $minimum) {
             if (!$minimum) {
                 continue;
@@ -55,15 +56,33 @@ final class RequiredCharacters implements PasswordValidatorInterface
 
             if ($actual < $minimum) {
                 if ('other' === $category) {
-                    throw new ValidatorException(
+                    $errors[] = new ValidatorException(
                         sprintf($this->translate('required.other'), $minimum, $configuration['other_chars'])
                     );
+                    continue;
                 }
 
-                throw new ValidatorException(sprintf($this->translate('required.' . $category), $minimum));
+                $errors[] = new ValidatorException(sprintf($this->translate('required.' . $category), $minimum));
             }
         }
 
+        if (count($errors) > 1) {
+            throw new ValidatorException(
+                sprintf(
+                    $this->translate('required.summary'),
+                    $require['uppercase'],
+                    $require['lowercase'],
+                    $require['numbers'],
+                    $require['other'],
+                    $configuration['other_chars']
+                )
+            );
+        }
+
+        if (count($errors) > 0) {
+            throw array_pop($errors);
+        }
+
         return true;
     }
 
@@ -89,7 +108,7 @@ final class RequiredCharacters implements PasswordValidatorInterface
                     return null;
                 }
 
-                return \strlen(preg_replace('/[^'.$chars.']+/', '', $string));
+                return \strlen(preg_replace('/[^' . $chars . ']+/', '', $string));
 
             default:
                 return null;
@@ -106,7 +125,7 @@ final class RequiredCharacters implements PasswordValidatorInterface
 
         $return = '';
         foreach (array_unique(preg_split('//u', $chars, -1, PREG_SPLIT_NO_EMPTY)) as $char) {
-            $return .= '\\'.$char;
+            $return .= '\\' . $char;
         }
 
         return $return;