symfony/symfony — pull request #3403 by vicb (2012-02-20 10:01:34+00:00)
Title: [WIP][Config] Improve prototype nodes usability, error messages, extensibility

### First commit

*Before*

```php
arrayNode('node')
->prototype('array')
// when the node is not set
->defaultValue(array('foo' => 'bar')
->children()
// when the key is not set
->scalarNode('foo')->defaultValue('bar')->end()

$root
->arrayNode('node')
->prototype('array')
// when the node is not set
->defaultValue(array('defaults' => array('foo1' => 'bar1', 'foo2' => 'bar2')
->children()
->arrayNode('bar')
// when the node is not set
->addDefautsIfNotSet()
// when some values are not set (node being set)
->scalarNode('foo1')->defaultValue('bar1')->end()
->scalarNode('foo2')->defaultValue('bar2')->end()
```

*after*

```php
arrayNode('node')
->addDefaultChildrenWhenNoneSet()
->prototype('array')
->children()
->scalarNode('foo')->defaultValue('bar')->end()

$root
->arrayNode('node')
->addDefaultChildrenWhenNoneSet()
->prototype('array')
->children()
->arrayNode('bar')
->scalarNode('foo1')->defaultValue('bar1')->end()
->scalarNode('foo2')->defaultValue('bar2')->end()
```

*more*

```php
arrayNode('node')
// Add a default node named 'defaults'
->addDefaultChildrenWhenNoneSet()
// Add a default node named 'foo'
->addDefaultChildrenWhenNoneSet('foo')
// Add two default nodes named 'foo', 'bar'
->addDefaultChildrenWhenNoneSet(array('foo', 'bar'))
// Add two default nodes
->addDefaultChildrenWhenNoneSet(2)
```

### Second commit

Improves error messages (print the path to the error) & extensibility.

@schmittjoh I would appreciate you feedback on both the commits. Do you think a boolean $throw switch on `getNode` would make sense (i.e. to prevent throwing excs in prod ?).

I still have to add one last commit updating the core bundles to take advantage of the first commit.