This PR was squashed before being merged into the 2.8 branch (closes#22036).Discussion----------Set Date header in Response constructor already| 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        |Setting the `Date` header in the `Response` constructor has been removed in#14912 and changed to a more lazy approach in `getDate()`.That way, methods like `getAge()`, `getTtl()` or `isFresh()` cause side effects as they eventually call `getDate()` and the Request "starts to age" once you call them.I don't know if this would be a nice test, but current behaviour is```php        $response = new Response();        $response->setSharedMaxAge(10);        sleep(20);        $this->assertTrue($response->isFresh());        sleep(5);        $this->assertTrue($response->isFresh());        sleep(5);        $this->assertFalse($response->isFresh());```A particular weird case is the `isCacheable()` method, because it calls `isFresh()` only under certain conditions, like particular status codes, no `ETag` present etc. This symptom is also described under "Cause of the problem" in#19390, however the problem is worked around there in other ways.So, this PR suggests to effectively revert#14912.Additionally, I'd like to suggest to move this special handling of the `Date` header into the `ResponseHeaderBag`. If the `ResponseHeaderBag` guards that we always have the `Date`, we would not need special logic in `sendHeaders()` and could also take care of#14912 (comment).Commits-------3a7fa7e Set Date header in Response constructor already

…pdonadio)This PR was squashed before being merged into the 3.2 branch (closes#22304).Discussion----------Moved $this->setDate() before the deprecation handling.| Q             | A| ------------- | ---| Branch?       | 3.2 <!-- see comment below -->| Bug fix?      | yes| New feature?  | no <!-- don't forget updating src/**/CHANGELOG.md files -->| BC breaks?    | no?| Deprecations? | no <!-- don't forget updating UPGRADE-*.md files -->| Tests pass?   | yes| Fixed tickets | #... <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | symfony/symfony-docs#... <!--highly recommended for new features--><!--- Bug fixes must be submitted against the lowest branch where they apply  (lowest branches are regularly merged to upper ones so they get the fixes too).- Features and deprecations must be submitted against the master branch.- Please fill in this template according to the PR you're about to submit.- Replace this comment by a description of what your PR is solving.-->#22036 merged the patch into the wrong place; the `$this->setDate()` happens after the deprecation handling, so it does not always get called.See alsohttps://www.drupal.org/node/2712647?page=1#comment-12025349Commits-------b6df4e7 Moved ->setDate() before the deprecation handling.

…pdonadio)This PR was squashed before being merged into the 3.2 branch (closes #22304).Discussion----------Moved $this->setDate() before the deprecation handling.| Q             | A| ------------- | ---| Branch?       | 3.2 <!-- see comment below -->| Bug fix?      | yes| New feature?  | no <!-- don't forget updating src/**/CHANGELOG.md files -->| BC breaks?    | no?| Deprecations? | no <!-- don't forget updating UPGRADE-*.md files -->| Tests pass?   | yes| Fixed tickets | #... <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | symfony/symfony-docs#... <!--highly recommended for new features--><!--- Bug fixes must be submitted against the lowest branch where they apply  (lowest branches are regularly merged to upper ones so they get the fixes too).- Features and deprecations must be submitted against the master branch.- Please fill in this template according to the PR you're about to submit.- Replace this comment by a description of what your PR is solving.-->symfony/symfony#22036 merged the patch into the wrong place; the `$this->setDate()` happens after the deprecation handling, so it does not always get called.See alsohttps://www.drupal.org/node/2712647?page=1#comment-12025349Commits-------b6df4e7 Moved ->setDate() before the deprecation handling.

…seHeaderBag (mpdude)This PR was squashed before being merged into the 3.4 branch (closes#22124).Discussion----------Shift responsibility for keeping Date header to ResponseHeaderBag| Q             | A| ------------- | ---| Branch?       | 3.4| Bug fix?      | no| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets || License       | MIT| Doc PR        |This is an improvement over#22036. It shifts responsibility for preserving a `Date` header to the `ResponseHeaderBag`.We already have similar logic there for the `Cache-Control` header.Commits-------5d83836 Shift responsibility for keeping Date header to ResponseHeaderBag