[RFC] Always available JSON extension

Hi internals,

I've created https://wiki.php.net/rfc/always_enable_json with an implementation at https://github.com/php/php-src/pull/5495

The proposal is to make it impossible to disable the JSON extension through configuration or build options,
and require that JSON be built statically instead of as a shared library
(to avoid linker errors or extension=json being commented out).

Currently, it's possible to disable the json extension with ./configure –disable-json.
However, JSON is extremely useful to have because it's widely used for many use cases
(web sites, logging output, and as a data format that can be used to share data with
many applications and programming languages),
so it would be useful for PHP maintainers and users to guarantee that json is always enabled.

Responses to earlier questions in my earlier thread "Moving json extension to core?" in https://externals.io/message/109783

In terms of getting it passed, I'd focus on just the first part, making
JSON a "core" builtin. Let the printf modifier be a separate RFC, or at
least a separate question.

Agreed - limiting this to making JSON a "core" builtin (similar to "hash" in 7.4) was my intent.
The printf comment was to measure interest in a potential followup RFC that would depend on this
(and give an example of internal functionality this would allow.).

At the risk of derailing... You can have your class implement the
interface unconditionally, then have a polyfill definition in your autoload
for cases where it doesn't exist. Obviously, it won't have an impact on
calls to json_encode(), but if the interface doesn't exist it's because
json_encode() doesn't either, so that should be harmless. :D

That would work for userland, but might cause problems if multiple PECL modules were to take that approach,
because they'd define duplicate classes.

Thanks,

• Tyson