Use associative array instead of numeric for exporters and erasers

[desrosj]

In https://core.trac.wordpress.org/ticket/43438#comment:34, it was suggested to use associative keys for the personal data exporters.

I think this is a good idea and should be done (and something that has to be done before the first iteration of these features is released).

Say a plugin adds their exporter, but they add it at the beginning of the list using array_unshift(). Or, a plugin just reorders the exporters. If a plugin hardcodes a change to the exporter at index 2, that is now inconsistent.

Using associative keys also allows things to be changed without having to iterate over every exporter in the list to find the one you need.

[allendav]

Change exporter and eraser arrays to associative arrays

[allendav]

Although plugins can continue to just push onto the exporter or eraser arrays in the filters, it would be better (for consistency) if they now used a slug, e.g.:

<?php
function register_my_plugin_exporter( $exporters ) {
  $exporters['comment-location-plugin'] = array(
    'exporter_friendly_name' => __( 'Comment Location Plugin' ),
    'callback'               => 'my_plugin_exporter',
  );
  return $exporters;
}

[johnjamesjacoby]

Patch looks like a nice improvement. +1

[ocean90]

The wp_privacy_personal_data_erasure_page filter should probably be changed to include the slug of the erasure instead of an arbitrary index number

Although plugins can continue to just push onto the exporter or eraser arrays in the filters, it would be better (for consistency) if they now used a slug,

Since this is a new API we can and should enforce that. This would simplify some of the odd error messages like "index cannot be less than one." or "index is out of range".

This should be solved before the first beta gets released.

[allendav]

Replying to ocean90:

The wp_privacy_personal_data_erasure_page filter should probably be changed to include the slug of the erasure instead of an arbitrary index number

Although plugins can continue to just push onto the exporter or eraser arrays in the filters, it would be better (for consistency) if they now used a slug,

Since this is a new API we can and should enforce that. This would simplify some of the odd error messages like "index cannot be less than one." or "index is out of range".

This should be solved before the first beta gets released.

Good idea. Working this now.

[allendav]

Filters changed to also include the key(slug) of the eraser/exporter

[desrosj]

43931.3.diff​ adds to 43931.2.diff​ by updating the error messages to use the text key instead of the numeric key.

[allendav]

Fix sprintf arguments (two places)

[iandunn]

In 43154:

Privacy: Store plugin callbacks in associative array for flexibility.

The personal data export and erasure tools allow plugins to register their own callbacks, in order to add additional data to the export and erasure processes. Previously, these were registered without specifying a constant identifier in the array of callbacks. Using mutable integers makes it difficult for plugins to modify the callbacks of other plugins, though.

Using associative array keys instead provides a covenient and reliable way to identify and interact with another plugin's callbacks.

Props desrosj, allendav, ocean90.
Fixes #43931.

[iandunn]

Reopening for backport to 4.9.

[azaozz]

In 43157:

Privacy: Store plugin callbacks in associative array for flexibility.

The personal data export and erasure tools allow plugins to register their own callbacks, in order to add additional data to the export and erasure processes. Previously, these were registered without specifying a constant identifier in the array of callbacks. Using mutable integers makes it difficult for plugins to modify the callbacks of other plugins, though.

Using associative array keys instead provides a covenient and reliable way to identify and interact with another plugin's callbacks.

Props desrosj, allendav, ocean90.
Merges [43154] to the 4.9 branch.
Fixes #43931.

[desrosj]

Moving to the new Privacy component.