Status: Needs Review

Thank you@gharlan.

This makes compatibility for older versions much harder as you still need to callroot() in those cases, while passing the name to the constructor was was already possible.

$treeBuilder =newTreeBuilder('rollerworks_password_strength');$rootNode =$treeBuilder->root('rollerworks_password_strength');// BC for Symfony < 4.2

What about checking if a name was already set in the constructor, and it equals the passed name.
In this case, return$this->root and do nothing, otherwise throw an deprecation instead.

To ensure forward compatibility you still need to check if theroot() method exists. But least you don't get any deprecation warnings.

$treeBuilder =newTreeBuilder('rollerworks_password_strength');if (method_exists($treeBuilder,'root')) {$rootNode =$treeBuilder->root('rollerworks_password_strength');// BC for Symfony < 4.2}else {$rootNode =$treeBuilder->getRootNode();}

As far as I know many libs already usemethod_exists.

Ah I completely missed#27476 😛

#27476 (comment) gives a good suggestion

$treeBuilder =newTreeBuilder("my_node");$rootNode =method_exists($treeBuilder,"getRootNode")    ?$treeBuilder->getRootNode()    :$treeBuilder->root("my_node");

👍