====== RFC: Always available hash extension  ======
  * Version: 1.0
  * Date: 2018-09-04
  * Author: Kalle Sommer Nielsen, kalle@php.net
  * Status: Implemented
  * First Published at: http://wiki.php.net/rfc/permanent_hash_ext

===== Introduction =====
This RFC proposes to make the hash extension (`ext/hash`) always available, similar to the `date`, `spl` & `pcre` extensions.

===== Proposal =====
The hash extension provides a very rich utility with many hashing algorithms which is extremely useful in modern day applications, not only in userland code but also very much in internals.

After a recent discussion on Github[1], Johannes proposed that the hash extension should be treated as special extension which cannot be disabled.

===== Backward Incompatible Changes =====

Build configurations that contain `--enable-hash` will have to be updated, as the argument will cease to exists. The `--with-mhash` argument will continue to stay.

===== Proposed PHP Version(s) =====

Target PHP version is the next master, which at the time of writing is most likely 7.4.

===== RFC Impact =====
==== To SAPIs and Existing Extensions ====

The only impact on SAPIs, Extensions and PECL extensions is that they can now always rely on the `hash` extension to be available and utilize its API without having external dependencies for such.

This naturally also means that minimal builds of PHP will slightly grow in size.

===== Unaffected PHP Functionality =====

Any already existing userland code will continue to work as before. Userland may remove calls to `extension_loaded('hash')` as they will now always return true.

The hash extension does not have any external dependencies, so this will not add any more dependencies for a minimal build of PHP.

===== Proposed Voting Choices =====

Since this touches a major component in the php-src source, the voting will require a 2/3 majority to pass.

===== Vote =====

As this is a language change, a 2/3 majority is required.

<doodle title="Make the hash extension always available as described in this RFC?" auth="kalle" voteType="single" closed="true">
   * Yes
   * No
</doodle>

===== Patches and Tests =====

  * Patch: https://gist.github.com/KalleZ/f9e50b36db608478617868057d2b9e77
  * Docs: http://svn.php.net/viewvc?view=revision&revision=346033

===== References =====

  * [1] https://github.com/php/php-src/commit/d6e81f0bfd0cb90586dd83d4fd47a4302605261a#commitcomment-29654178