Latest commit 9d9f628 Apr 27, 2017 @nicolas-grekas nicolas-grekas minor #22531 Throwing an exception if the class is not found (weaverr…
…yan)

This PR was squashed before being merged into the 3.3-dev branch (closes #22531).

Discussion
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Throwing an exception if the class is not found

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

We now throw an exception if the user makes a mistake with their PSR-4 prefix and namespace. For example:

```yml
AppBundle\Controller\:
    resource: '../../src/AppBundle/{Controller}'
    public: true
```

I should not have the `\Controller` at the end of the key. Previously, it would silently not import any services from the directory. Now it throws:

> Expected to find class "AppBundle\Controller\Controller\Admin\BlogController" in file "/path/to/project/src/AppBundle/Controller/Admin/BlogController.php" while importing services from resource "../../src/AppBundle/{Controller}", but it was not found! Check the namespace prefix used with the resource.

The only "downside" is that this prevents someone from importing files from a resource that has a file with no class in it (`functions.php`). @nicolas-grekas and I decided today that we can throw an exception now to be safe, and see if anyone has that valid use-case.

Cheers!

Commits
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e85bcc9 Throwing an exception if the class is not found