Warning in TwigDeprecationAnalyzer when the error caught is not in a twig file

Thanks for this, helped a lot,
yes it looks like ctools needs to cut a release 3.15
3.14 doesn't do it, but 3.x-dev fixes the issue.

So we are using https://github.com/twigphp/Twig/blob/3.x/src/Util/DeprecationCollector.php to collect the Twig deprecation errors. All that does is it sets its own error handler and collects all deprecation errors reported while compiling the Twig templates. It does not collect the file name and line number for the error messages though. I think we should subclass that and in case the error message does not come with a twig file name and line number, we should include the file name and line number from set_error_handler() that is currently not saved.

    public function collect(\Traversable $iterator): array
    {
        $deprecations = [];
        set_error_handler(function ($type, $msg) use (&$deprecations) {
            if (\E_USER_DEPRECATED === $type) {
                $deprecations[] = $msg;
            }
        });

        foreach ($iterator as $name => $contents) {
            try {
                $this->twig->parse($this->twig->tokenize(new Source($contents, $name)));
            } catch (SyntaxError $e) {
                // ignore templates containing syntax errors
            }
        }

        restore_error_handler();

        return $deprecations;
    }

This way we can keep reporting Twig level errors when they are twig level (like we do now) and we can also report the runtime errors found while parsing the twig file with their PHP file/line source information that are currently leading to the fails.

Created oldfashoned patch to include because .diff can change without notice.

Fails were due to the newly introduced catching of twig syntax errors.

Was looking into adding a test on 3rd party deprecations triggered from Twig compile but at least the trigger for this issue in #3325685: condition_info_alter deprecation triggers false possitive deprecation notices was resolved by removing the deprecation notice there and it was erroneously triggered widely :D Either way those could still show up with this, and the tests already prove that there is no regression. Also we gained a new feature of syntax errors reported from Twig compilation, which is good IMHO.