Use LegacyEventDispatcherProxy for Symfony 4.3

[XWB]

This should fix the following deprecation message:

User Deprecated: Calling the "Symfony\Component\EventDispatcher\EventDispatcherInterface::dispatch()" method with the event name as first argument is deprecated since Symfony 4.3, pass it second and provide the event object first instead.

[XWB]

It seems Travis fails due to an unrelated error:

Undefined index: trace_level

[dbu]

weird, that was a bug in symfony that i thought i fixed already once: symfony/symfony#32802

[dbu]

do you have time to debug that one locally?

looking at https://github.com/symfony/symfony/blob/v4.3.6/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php#L97 i can't see how this could ever happen with v4.3.6 of symfony/http-kernel so we would have to debug if the kernel somehow does not get instantiated properly or some assumption about the options is wrong.

btw looking at my "fix" again, i notice that trace_level already was initialized in the defaults and my change was pointless, just complicating the code a bit.

[dbu]

dug around the code a bit, i think the problem is with

FOSHttpCache/src/Test/EventDispatchingHttpCacheTestCase.php

Lines 48 to 50 in 01d87fa

	->getMockBuilder($this->getCacheClass())
	->setMethods($mockedMethods)
	->disableOriginalConstructor()

we create a partial mock. dangerous territory 😱
i guess we should change getHttpCachePartialMock to always mock the addTraces method to avoid the issue.

[XWB]

@dbu Nice find. Disabling the original constructor is a classic pitfall :) I just pushed another commit that fixes the unit tests.

There is still one test failing but seems to be a totally different issue:

Exception occurred:
File "/usr/lib/python2.7/dist-packages/sphinx/locale/init.py", line 191, in _
return translators['sphinx'].ugettext(message)
KeyError: 'sphinx'

[dbu]

thank you!

yeah the sphinx build would be to check the documentation. i try to fix it in #450 but did not find why it was not working, and then did not find more time to continue...