PHP7 return types incompatibile with generate code

[mikeymike]

Preconditions

1. PHP 7.0.8 (any compatible PHP 7 release should be sufficient though)

Steps to reproduce

1. Blank install
2. Create a new block and add a method with a return type in PHP7 format e.g : string
3. Use the block in some layout somewhere
4. Hit the frontend to use the block

Expected result

1. The page should load and the block code be executed correctly

Actual result

Instead you get a fatal error from PHP because the generated interceptor class doesn't have a return type at all.

PHP Fatal error:  Declaration of XX\YY\Block\CustomBlock\Interceptor::someMethod() must be compatible with XX\YY\Block\CustomBlock\::someMethod(): bool in .../var/generation/XX/YY/Block/CustomBlock/Interceptor.php on line X

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This of course can be a tricky one to resolve purely based on the fact you wouldn't want to break BC with PHP 5.X.

The only resolutions I can think of at this point is...

1. Check the version at runtime
2. Set the PHP version (like we set the deploy mode)

[AydinHassan]

It seems the version of zendframework/zend-code Magento 2 ships with does not support return type hints in code generation, nor is it easy to update the version of zendframework/zend-code due to conflicting dependencies.

We decided to temporarily patch this and bring in some zendframework/zend-code features to add return type hints. Here is a patch if anyone else wants this feature: https://gist.github.com/AydinHassan/064f4bbd33fc118f9fa655811df6a660.

Note that you will need to put it in your own module and rename the namespaces.

[mwgamble]

As the scanner code in the zend-code library is now set to be deprecated and removed, Magento should look towards replacing this altogether with another library.

zendframework/zend-code#91

[adragus-inviqa]

M2 took "ownership" of ZF code, but I agree that the package should be replaced. But that's even more refactoring.
Maybe use another strategy for PHP 7+ (\Magento\Framework\Code\Generator\CodeGeneratorInterface) and keep the current one for older versions.

[tkacheva]

internal issue MAGETWO-59661

[mcjwsk]

@tkacheva any updates on this issue ?

[orlangur]

Create a new block and add a method with a return type in PHP7 format e.g : string

Interesting case :) Never thought of writing PHP5-incompatible code within Magento 2.

@AydinHassan

nor is it easy to update the version of zendframework/zend-code due to conflicting dependencies

https://github.com/zendframework/zend-code/blob/release-3.1.0/composer.json#L17 which dependencies?

@mwgamble

As the scanner code in the zend-code library is now set to be deprecated and removed, Magento should look towards replacing this altogether with another library

Why another library if it is BC break anyway? Why not simply stick to zend-code 3.x?

At first glance https://github.com/zendframework/zend-code/blob/master/doc/book/migration.md does not seem to be really painful.

If you generate code that should run in PHP 5.x, it is advisable to ...

And this sentence looks exactly like the our case: we can use fancy new PHP7 features while all generated code will remain PHP5-compatible.

[mwgamble]

Why another library if it is BC break anyway? Why not simply stick to zend-code 3.x?

Because zend-code 3.x will never have support for scanning code that uses scalar type declarations.

[orlangur]

@mwgamble aren't they supported since version 3.0.0? https://github.com/zendframework/zend-code/blob/master/CHANGELOG.md#300---2016-01-13

[mwgamble]

@orlangur nope. see here: zendframework/zend-code#56

Also see the responses to my comments here: zendframework/zend-code#87 (comment)
And here: zendframework/zend-code#85

[orlangur]

@mwgamble, thanks for the details, I'll look closer into it. If scanner will not be adopted in 3.x and then deprecated-removed in 4.x-5.x it's a problem :)

So, it's better switch to BetterReflection library for us?