…erator interface (Toflar)

This PR was merged into the 2.8 branch.

Discussion
----------

[Routing] Fixed the interface description of the url generator interface

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

The `UrlGenerator` has always been able to return `null`. Many tests assert this for many years but the interface actually always only allowed a `string` return.

Examples for tests:

- https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php#L206
- https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php#L217
- https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php#L471

So I think I would not consider this change as a BC break but rather a doc fix because it seems like `null` has always been an accepted return value.

Commits
-------

d2e9e0b Fixed the interface description of the url generator interface

… url generator interface (Toflar)"

This reverts commit 487f8ac, reversing
changes made to cf359c2.

* 2.8:
  [appveyor] fix
  Revert "minor #28321 [Routing] Fixed the interface description of the url generator interface (Toflar)"
  remove cache warmers when Twig cache is disabled
  [HttpKernel][FrameworkBundle] Fix escaping of serialized payloads passed to test clients
  chore: rename Appveyor filename
  Fixed the interface description of the url generator interface
  Format file size in validation message according to binaryFormat option

* 3.4:
  [appveyor] fix
  Revert "minor #28321 [Routing] Fixed the interface description of the url generator interface (Toflar)"
  Fixed caching of templates in default path on cache warmup
  remove cache warmers when Twig cache is disabled
  [HttpKernel][FrameworkBundle] Fix escaping of serialized payloads passed to test clients
  chore: rename Appveyor filename
  Fixed the interface description of the url generator interface
  Format file size in validation message according to binaryFormat option

* 4.1:
  [appveyor] fix
  [DI] Fix dumping some complex service graphs
  Revert "minor #28321 [Routing] Fixed the interface description of the url generator interface (Toflar)"
  Fixed caching of templates in default path on cache warmup
  added missing LICENSE file
  remove cache warmers when Twig cache is disabled
  [Workflow] Make sure we do not run the next transition on an updated state
  change baseUrl to basePath to fix wrong profiler url
  [HttpKernel][FrameworkBundle] Fix escaping of serialized payloads passed to test clients
  chore: rename Appveyor filename
  Fixed the interface description of the url generator interface
  Format file size in validation message according to binaryFormat option

Description
-----------

As outlined in symfony/symfony#28321 we cannot rely on the url generator of the router to always return a string. This was an issue in the interface docs of Symfony.

Commits
-------

5aaf547 Fixed unhandled null case in contao framework
ef39a73 Added unit test
10268b1 Rename the test method

Description
-----------

As outlined in symfony/symfony#28321 we cannot rely on the url generator of the router to always return a string. This was an issue in the interface docs of Symfony.

Commits
-------

5aaf5471 Fixed unhandled null case in contao framework
ef39a735 Added unit test
10268b10 Rename the test method

…ce::generate to remove null (shieldo)

This PR was merged into the 3.4 branch.

Discussion
----------

[Routing] revert the return type for UrlGeneratorInterface::generate to remove null

…to remove null

| Q             | A
| ------------- | ---
| Branch?       | 3.4 (only)
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

Bit of a casualty of commit tennis this:

A change to add `null` here as an option for how `UrlGeneratorInterface::generate()` (rather than the concrete `UrlGenerator`) was merged in #28321, but then [reverted](90494c2) for the reason [that this could be seen as a BC break](#28321 (comment)), as the `null` return had not previously been documented (and is still not as part of the interface method docs).

However, in a subsequent change (#33252) with a wider scope, this doc change was added _back_ in order to reflect the underlying implementation as a result of a PHPStorm plugin complaining. There's no indication though of what a `null` return here though would mean, and for the same reason as the first revert (that this should be seen as a BC break), I'd like to submit this to be reverted for the 3.4 branch. (In 4.4 the `null` has already been removed.)

Having the interface indicating that this method can return `null` necessitates introducing a lot of actually redundant null checks in code that is covered by static analysis tools such as PHPStan.

Commits
-------

9f853f3 [Routing] revert the return type for UrlGeneratorInterface::generate to remove null