Remove zend json from theme

[dmanners]

Description

Since Zend Framework1 is EOL we should replace the usages. In this PR I replace the usage of Zend_Json in Magento Theme with the new serializer class. Part of the #9236 task.

Fixed Issues (if relevant)

1. Upgrade ZF components. Zend_Json #9236
2. ...

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[adragus-inviqa]

All this looks ok, but I was just wondering: seeing how the M2 JSON serializer is only a dumb wrapper over json decode/encode, how would we handle encoding/decoding errors? We'd have to use json_last_error() now? At least Zend_Json had exceptions...

I'm saying this, because this PR removes a try/catch block that would've been otherwise useful. And said try/catch block was around a cookie read no less. Aka user input. You should never trust that. Imagine json_decode($_GET['param']) and not checking for errors. Not cool.

[dmanners]

Yup @adragus-inviqa I was thinking about something similar to Zend https://github.com/zendframework/zend-json/blob/3426c66e689120a384a370df2cf35745f1b15b2c/src/Json.php#L230 or symfony https://github.com/symfony/serializer/blob/80e172d62cdac03df4a0fd8bcef8513bf9d2aa83/Encoder/JsonDecode.php#L80 and then process the exceptions.

[adragus-inviqa]

Well, yes, that's what I mean. But that also means that the behaviour of the serializer must change, breaking compatibility, because it doesn't throw at the moment.

And since it's a BC break, they won't allow it. Your best option is a new SerializeWithThrow decorator or something, wrapping the original one. That should also be a new PR, btw.

---

Or maybe we can add a new method to the existing Serializer called getErrors() or something? This way, we won't be breaking BC. I'm not sure about this way of doing things, as people might forget to check the errors, but it's an alternative.

[dmanners]

Yeah, I think having another class specifically to deal with json throwing an exception is a bit of overkill. I will put together a PR for the serializer with the exception handling and see what the core Magento team say.

[okorshenko]

@dmanners @adragus-inviqa thank you for raising the issue with Exceptions. This is known issue for us and Magento Core Team is looking for proper solution right now.

[magento-team]

@dmanners Thank you for the contribution