Cannot register extension from Kernel::build #25660
Description
| Q | A |
|---|---|
| Bug report? | yes |
| Feature request? | no |
| BC Break report? | no |
| RFC? | no |
| Symfony version | 4.0.2 |
ContainerBuilder::registerExtension calls are ignored if called from Kernel build method, thus the extensions are not merged into the final container.