… an unsupported type (Deuchnord)This PR was merged into the 4.3 branch.Discussion----------[Cache] Log a more readable message when trying to cache an unsupported type| Q             | A| ------------- | ---| Branch?       | master| Bug fix?      | no| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets |#29710   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        |Improved the warning risen when trying to save something that has a non-supported type in the Simple cache.For instance, let's say the following code:```phpclass TestCommand extends Command{    private $cache;    public function __construct(CacheInterface $cache)    {        parent::__construct();        $this->cache = $cache;    }    // ...    protected function execute(InputInterface $input, OutputInterface $output)    {        $n = $this->cache->get('n', function () {            return function () {                return rand(0,10);            };        });        dump($n());    }}```Running this code will give the following:```14:32:03 WARNING   [cache] Could not save key "n" in cache: the Closure type is not supported.0```Commits-------21ba3c0 [Cache] Log a more readable error message when saving into cache fails

This PR was merged into the 4.3 branch.Discussion----------[Cache] improve logged messages| Q             | A| ------------- | ---| Branch?       | 4.3| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets | -| License       | MIT| Doc PR        | -This was improved already in#31395, but the patch was incomplete.This PR fixes this.Commits-------257f3f1 [Cache] improve logged messages

This PR was squashed before being merged into the 4.3 branch (closes#31864).Discussion----------[Cache] Fixed undefined variable in ArrayTrait| Q             | A| ------------- | ---| Branch?       | 4.3| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets || License       | MIT| Doc PR        |So once again (see#29591) my test suite managed to find an error in ArrayTrait in cache. This time it was this PR:#31395 later improved by#31590 that introduced `$id` to logging, which I guess should be `$key`? So this PR changes it to `$key`, ~but my tests **still fail** as there is no `$this->namespace` in `ArrayAdapter` (is this the only class that uses this ArrayTrait?). But I don't know what to do about it. Maybe@nicolas-grekas has some answers?~Commits-------8568923 [Cache] Fixed undefined variable in ArrayTrait