Always display message for AbstractRelated rule

`NestedValidationException` should include all `AbstractRelated` rule
exceptions.

`AbstractRelated` rule failures always indicate an interesting nested
context, which should not be omitted from the final result.

`NonOmissibleExceptionInterface` is a marker interface for
exceptions thrown by instances of `AbstractRelated`, which
facilitates identification of those rules' exceptions with
`instanceof`.

library/Exceptions/AttributeException.php

@@ -11,7 +11,7 @@
 
 namespace Respect\Validation\Exceptions;
 
-class AttributeException extends NestedValidationException
+class AttributeException extends NestedValidationException implements NonOmissibleExceptionInterface
 {
     const NOT_PRESENT = 0;
     const INVALID = 1;

library/Exceptions/CallException.php

@@ -11,6 +11,6 @@
 
 namespace Respect\Validation\Exceptions;
 
-class CallException extends GroupedValidationException
+class CallException extends GroupedValidationException implements NonOmissibleExceptionInterface
 {
 }

library/Exceptions/KeyException.php

@@ -11,7 +11,7 @@
 
 namespace Respect\Validation\Exceptions;
 
-class KeyException extends AttributeException
+class KeyException extends AttributeException implements NonOmissibleExceptionInterface
 {
     public static $defaultTemplates = [
         self::MODE_DEFAULT => [

library/Exceptions/KeyNestedException.php

@@ -11,7 +11,7 @@
 
 namespace Respect\Validation\Exceptions;
 
-class KeyNestedException extends AttributeException
+class KeyNestedException extends AttributeException implements NonOmissibleExceptionInterface
 {
     public static $defaultTemplates = [
         self::MODE_DEFAULT => [

library/Exceptions/KeySetException.php

@@ -11,7 +11,7 @@
 
 namespace Respect\Validation\Exceptions;
 
-class KeySetException extends GroupedValidationException
+class KeySetException extends GroupedValidationException implements NonOmissibleExceptionInterface
 {
     const STRUCTURE = 2;
 

library/Exceptions/NestedValidationException.php

@@ -122,6 +122,26 @@ class NestedValidationException extends ValidationException implements IteratorA
         return $recursiveIteratorIterator;
     }
 
+    /**
+     * Returns weather an exception should be omitted or not.
+     *
+     * @param ExceptionInterface $exception
+     *
+     * @return bool
+     */
+    private function isOmissible(ExceptionInterface $exception)
+    {
+        if (!$exception instanceof self) {
+            return false;
+        }
+
+        $relatedExceptions = $exception->getRelated();
+        $relatedExceptions->rewind();
+        $childException = $relatedExceptions->current();
+
+        return $relatedExceptions->count() === 1 && !$childException instanceof NonOmissibleExceptionInterface;
+    }
+
     /**
      * @return SplObjectStorage
      */
@@ -136,9 +156,7 @@ class NestedValidationException extends ValidationException implements IteratorA
         $lastDepthOriginal = 0;
         $knownDepths = [];
         foreach ($recursiveIteratorIterator as $childException) {
-            if ($childException instanceof self
-                && $childException->getRelated()->count() > 0
-                && $childException->getRelated()->count() < 2) {
+            if ($this->isOmissible($childException)) {
                 continue;
             }
 

library/Exceptions/NonOmissibleExceptionInterface.php

@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Exceptions;
+
+interface NonOmissibleExceptionInterface extends ExceptionInterface
+{
+}

tests/integration/assert-with-attributes.phpt

@@ -0,0 +1,53 @@
+--FILE--
+<?php
+require 'vendor/autoload.php';
+use Respect\Validation\Exceptions\NestedValidationException;
+use Respect\Validation\Validator as v;
+
+try {
+    $array = [
+        'mysql' => [
+            'host' => 42,
+            'user' => 'user',
+            'password' => 'password',
+            'schema' => 'schema',
+        ],
+        'postgresql' => [
+            'host' => 'host',
+            'user' => 42,
+            'password' => 'password',
+            'schema' => 'schema',
+        ],
+    ];
+    $object = json_decode(json_encode($array));
+    v::create()
+        ->attribute(
+            'mysql',
+            v::create()
+                ->attribute('host', v::stringType(), true)
+                ->attribute('user', v::stringType(), true)
+                ->attribute('password', v::stringType(), true)
+                ->attribute('schema', v::stringType(), true),
+            true
+        )
+        ->attribute(
+            'postgresql',
+            v::create()
+                ->attribute('host', v::stringType(), true)
+                ->attribute('user', v::stringType(), true)
+                ->attribute('password', v::stringType(), true)
+                ->attribute('schema', v::stringType(), true),
+            true
+        )
+        ->setName('the given data')
+        ->assert($object);
+} catch (NestedValidationException $exception) {
+    echo $exception->getFullMessage().PHP_EOL;
+}
+?>
+--EXPECTF--
+- All of the required rules must pass for the given data
+  - These rules must pass for mysql
+    - host must be a string
+  - These rules must pass for postgresql
+    - user must be a string

tests/integration/issue-796.phpt

@@ -0,0 +1,51 @@
+--FILE--
+<?php
+require 'vendor/autoload.php';
+use Respect\Validation\Exceptions\NestedValidationException;
+use Respect\Validation\Validator as v;
+
+try {
+    v::create()
+        ->key(
+            'mysql',
+            v::create()
+                ->key('host', v::stringType(), true)
+                ->key('user', v::stringType(), true)
+                ->key('password', v::stringType(), true)
+                ->key('schema', v::stringType(), true),
+            true
+        )
+        ->key(
+            'postgresql',
+            v::create()
+                ->key('host', v::stringType(), true)
+                ->key('user', v::stringType(), true)
+                ->key('password', v::stringType(), true)
+                ->key('schema', v::stringType(), true),
+            true
+        )
+        ->setName('the given data')
+        ->assert([
+            'mysql' => [
+                'host' => 42,
+                'user' => 'user',
+                'password' => 'password',
+                'schema' => 'schema',
+            ],
+            'postgresql' => [
+                'host' => 'host',
+                'user' => 42,
+                'password' => 'password',
+                'schema' => 'schema',
+            ],
+        ]);
+} catch (NestedValidationException $exception) {
+    echo $exception->getFullMessage().PHP_EOL;
+}
+?>
+--EXPECTF--
+- All of the required rules must pass for the given data
+  - These rules must pass for mysql
+    - host must be a string
+  - These rules must pass for postgresql
+    - user must be a string