The stream context inside `mysqlnd_vio::enable_ssl()` is leaking.
In particular: when `php_stream_context_set()` get called the refcount
of `context` is increased by 1, which means that `context` will now
have a refcount of 2. Later on we remove the context from the stream
by calling `php_stream_context_set(stream, NULL)` but that leaves our
`context` with a refcount of 1, and therefore it's never destroyed.
In my test case this yielded a leak of 1456 bytes per connection
(but could be more depending on your settings ofc).
Annoyingly, Valgrind doesn't find it because the context is still
in the `EG(regular_list)` and will thus be destroyed at the end of
the request. However, I still think this bug needs to be fixed because
as the users in the issue report already mentioned:
there can be long-running PHP scripts.
Fix it by decreasing the refcount to transfer the ownership.
Closes GH-10909.
Niels Dossche
8930bf8c33