Start PHP 8.0 support

[Slamdunk]

Close #46

[Ocramius]

In order for this to work, we still need to make sure laminas-code does not crash with:

• union types
• mixed type
• static return type
• throw expression (foo() ?? throw new \Exception();)
• match expression
• null-safe expression (?->)
• non-capturing catch (try {} catch (\Exception) { return; })
• named arguments calls
• attributes
• trailing comma in function arguments
• variadic ReflectionFunction::invoke(), ReflectionClass::newInstance(), ReflectionMethod::invoke()
• ctor property promotion

This is a lot of work that requires much more care for this specific package :S

[Slamdunk]

If you agree, I'll do my best at least to start the support with the current test suite. I've renamed the PR accordingly: is it ok for you?

[Ocramius]

@Slamdunk if you have time/willpower to throw at the problem, I can gladly support you! This has been on my to-do list as well, since ocramius/proxy-manager is highly dependant on laminas/laminas-code, and an upgrade to PHP 8 will be due soon there too :-)

[Ocramius]

@Slamdunk an alternative (which had already be planned, but can't find where) is to drop all the scanner components from laminas/laminas-code: that's less effort, and I don't mind releasing a new major version of this package without that stuff.

That effectively means that everything that has to do with token changes can be removed, and therefore half the work is gone.

[Slamdunk]

Where should I put the backword compatibility definitions for the new constants?

[Ocramius]

Anywhere you want, as long as it's @internal, I suppose?

[Slamdunk]

Analyzing the source, \Laminas\Code\Scanner\TokenArrayScanner::scan seems the right place: https://github.com/laminas/laminas-code/pull/47/files#diff-c08ce1832ae9f8788d45e1cf8fa62d743ede600c44a4e622ec20b4b684383320R383
Had a run with --process-isolation, and everything works fine.

[Slamdunk]

@Ocramius well, I just made tests passing on PHP 8.0, I only need to make the BC, see #47 (comment)

[Slamdunk]

if you have time/willpower to throw at the problem

From what you wrote, you clearly have much wider perspective on the overall future of this library.
Here I'm just trying to make everything run without fatal errors on PHP 8.0 as I'm upgrading my apps to be ready as soon as possible, so my work stops here for laminas-code.

May I ask you if this PR can be tagged after merge so I can continue my work on laminas-form (laminas/laminas-form#75)?

[weierophinney]

🚢