Fixes #1042 Fix PHP preloading

[annuh]

This PR should fix the following warning when using PHP autoloading with Symfony:

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Nodes\HotThreads, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 11

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Nodes\Info, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 12

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Nodes\ReloadSecureSettings, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 13

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Nodes\Stats, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 14

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Nodes\Usage, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 15

Warning: Cannot declare class \Elasticsearch\Endpoints\Cluster\Settings\Get, because the name is already in use in /var/www/html/vendor/elasticsearch/elasticsearch/src/autoload.php on line 16

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[ezimuel]

@annuh thanks for this PR. I have only one question, why is false the autoloading in class_exists()?

[annuh]

@annuh thanks for this PR. I have only one question, why is false the autoloading in class_exists()?

I though $autoload = false would be a bit faster, but it should work in both ways. See also: https://www.php.net/manual/en/function.class-exists.php#113852

Do you prefer this check without the $autoload = true option?

[ezimuel]

If #1042 issue is related to the preloading feature of PHP I think we can use false since it means the alias has alrean been loaded during preload. I would like to test it before merge. I asked for more information about the preload configuration here #1042 (comment).
@annuh can you test if it works with true and false as second parameter of class_exists()? Thanks.
I'll also try to build a test case for that.

[ezimuel]

@annuh I did some test using the opcache.preload feature with true and false. It seems ok in both cases. We can use false, as you suggested. Thanks for the PR. I'll merge soon.

[ezimuel]

Just released elasticsearch-php 7.9.0 with #1051 included