Fixes #917: Allow Robo to be used with Symfony 5.

[greg-1-anderson]

Overview

This pull request:

• Fixes a bug
• Adds a feature
• Breaks backwards compatibility
• Has tests that cover changes
• Adds or fixes documentation

Summary

Allow Symfony 5.

[greg-1-anderson]

There's a test failure here from EventDispatcher::dispatch() that needs an API update.

We also have a problem with Symfony/Process requiring a factory method instead of a constructor to use a string parameter to exec. We might need to test which version of Symfony/Process we have, as the new factory method is not available in older versions of Symfony/Process (and we'd need to do a major version bump to drop old Symfony/Process versions).

[alsar]

The event dispatcher in v5 changed the parameter signature from string to object. So there needs to be a check (via reflection) which type the function accepts.

For the Process component a simple method_exists check should suffice

[alsar]

The method fromShellCommandline is already available since version 4.2 so there should be no problem to change new Process($this->getCommand(), getcwd()) to Process::fromShellCommandline($this->getCommand(), getcwd()) because Robo requires symfony/process ^4.4.3|^5.

[greg-1-anderson]

I forgot that I already dropped support for older versions of Symfony/Process in Robo 2. That turns out to have been foresightful; makes things easier here.

[c33s]

i won't drop support for a symfony version which is still supported. https://symfony.com/releases/3.4 End of bug fixes: November 2020 End of security fixes: November 2021

a task runner should be compatible with legacy php and symfony versions as long as possible. bc layers would be awesome.

just my opinion

[greg-1-anderson]

Yeah, with more maintainers maybe it wouldn't be a big deal to include more Symfony versions. There's still the Robo 1.x branch for Symfony 3. If you need Symfony 3 AND Symfony 5, you could consider back-porting this PR to the 1.x branch.

Pretty soon we have to think about Composer 2 as well, though; limiting supported versions greatly reduces the testing permutations.

[greg-1-anderson]

For those who wish to support a wide variety of Symfony versions, "consolidation/robo": "^1 | ^2" should work well in many instances. The Robo 1.x and 2.x APIs are pretty similar.

[greg-1-anderson]

This fixed many incompatibilities between Robo and Symfony 5, but not all.