bug #24633 [Config] Fix cannotBeEmpty() (ro0NL)

This PR was merged into the 3.4 branch.

Discussion
----------

[Config] Fix cannotBeEmpty()

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #24614
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!--highly recommended for new features-->

Open for better deprecation message, but this should clarify.

cc @iltar

Commits
-------

2269f70180 [Config] Fix cannotBeEmpty()

src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php

@@ -424,7 +424,11 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
                 $node->setKeyAttribute($this->key, $this->removeKeyItem);
             }
 
-            if (true === $this->atLeastOne || false === $this->allowEmptyValue) {
+            if (false === $this->allowEmptyValue) {
+                @trigger_error(sprintf('Using %s::cannotBeEmpty() at path "%s" has no effect, consider requiresAtLeastOneElement() instead. In 4.0 both methods will behave the same.', __CLASS__, $node->getPath()), E_USER_DEPRECATED);
+            }
+
+            if (true === $this->atLeastOne) {
                 $node->setMinNumberOfElements(1);
             }
 
@@ -486,9 +490,7 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
         }
 
         if (false === $this->allowEmptyValue) {
-            throw new InvalidDefinitionException(
-                sprintf('->cannotBeEmpty() is not applicable to concrete nodes at path "%s"', $path)
-            );
+            @trigger_error(sprintf('->cannotBeEmpty() is not applicable to concrete nodes at path "%s". In 4.0 it will throw an exception.', $path), E_USER_DEPRECATED);
         }
 
         if (true === $this->atLeastOne) {

src/Symfony/Component/Config/Tests/Definition/Builder/ArrayNodeDefinitionTest.php

@@ -54,7 +54,6 @@ class ArrayNodeDefinitionTest extends TestCase
             array('defaultValue', array(array())),
             array('addDefaultChildrenIfNoneSet', array()),
             array('requiresAtLeastOneElement', array()),
-            array('cannotBeEmpty', array()),
             array('useAttributeAsKey', array('foo')),
         );
     }
@@ -298,6 +297,20 @@ class ArrayNodeDefinitionTest extends TestCase
         $this->addToAssertionCount(1);
     }
 
+    /**
+     * @group legacy
+     * @expectedDeprecation Using Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition::cannotBeEmpty() at path "root" has no effect, consider requiresAtLeastOneElement() instead. In 4.0 both methods will behave the same.
+     */
+    public function testCannotBeEmpty()
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->cannotBeEmpty()
+            ->integerPrototype();
+
+        $node->getNode()->finalize(array());
+    }
+
     public function testSetDeprecated()
     {
         $node = new ArrayNodeDefinition('root');
@@ -313,15 +326,13 @@ class ArrayNodeDefinitionTest extends TestCase
     }
 
     /**
-     * @expectedException \Symfony\Component\Config\Definition\Exception\InvalidConfigurationException
-     * @expectedExceptionMessage The path "root" should have at least 1 element(s) defined.
+     * @group legacy
+     * @expectedDeprecation ->cannotBeEmpty() is not applicable to concrete nodes at path "root". In 4.0 it will throw an exception.
      */
-    public function testCannotBeEmpty()
+    public function testCannotBeEmptyOnConcreteNode()
     {
         $node = new ArrayNodeDefinition('root');
-        $node
-            ->cannotBeEmpty()
-            ->integerPrototype();
+        $node->cannotBeEmpty();
 
         $node->getNode()->finalize(array());
     }