Import QTS slugs options and meta data into QTX

[herrvigg]

When slugs is uninstalled all QTS data are erased and will be lost for QTX. The options and meta data from the legacy plugin should be properly imported in QTX to separate entries.

Add new features in the import settings to migrated QTS data:

• QTS postmeta / termmeta slugs are migrated renaming _qts_slug_ prefix to qtranslate_slug_ prefix.
• QTS qts_options slugs are migrated to qtranslate_module_slugs options, after removing the _qts_ prefix for each type entry.

ATTENTION: existing slugs options and meta before migration are erased! A confirmation is required. Without this, a dry-run mode allows to see the effects before change.

Update prefix constants accordingly for QTX:

• rename QTS_META_PREFIX to QTX_SLUGS_META_PREFIX
• delete QTS_PREFIX made obsolete.

Add a new admin notice to suggest import when old QTS options and meta are found. The import can be done manually by the admin at any time.
Remove most of the HTML id attributes from the Slugs settings form, not needed (name attributes matter).

[herrvigg]

@spleen1981 please check this carefully on your side and let me know how it goes before merging it.

Attention: the current options that may have been changed during the last commits in master (stored in qtranslate_module_slugs) will be erased during import. The legacy QTS options are unchanged in any case.

This solves several issues of migration on activation which are hard to maintain and may create problems in the future. The main idea here is that manual import from QTS is required before being able to use slugs in QTX.

[herrvigg]

Good remarks

[herrvigg]

@spleen1981 I'm starting to think this is getting too complicated for what we need... and the problem of QTS cleanup is not solved yet. What about doing a import-migration instead?

1. delete all existing QTX config about slugs
2. import options and meta from QTS by renaming the keys.

No selective import, it's all or nothing. It looks like my first solution but the QTS legacy is not kept anymore, it's a full transfer.

Pros:

• simpler: less code, clearer consequence of the action
• solves the problem of QTS cleanup at the same time as all is moved. No leftovers in QTS.

Cons:

• the migration is irreversible from the admin panel. If old keys wanted to be restored it's possible but it has to be done by hand in SQL. But normally there's literally no reason to continue using QTS after import. The labels will made clearer. Admin should still do a DB backup before.
• current changes done in options (not meta) on master branch would be lost, but that affects very few people (developers like you who are testing slugs). Imo not worth handling this in the regular source base. The changes should be limited as the QTS values still exist at this point.

[spleen1981]

@herrvigg this solution is much better IMO, cons are not an issue as the legacy plugin is dead and is an external module anyways. I liked this approach more from the beginning, the simpler the better.

[herrvigg]

OK - finally! The new version is much simpler, it becomes a migration as described above:

1. delete all existing QTX config about slugs
2. import options and meta from QTS by renaming the keys.

There's a step 0, I added a temporary hack to preserve the options for master dev (solving cons point 2)! There was a nasty side effect of saving new options with new keys leading to empty slugs. The hack restores the previous QTS options as before so the migration falls back to the general case again (I didn't think about meta data at that time). It's really ugly but this will go away before release. Normal QTS users don't need this.

The patch should be ready for review. For security, save the content of option_name = qtranslate_module_slugs before confirming migration. The meta data are easy to recover if you want to repeat the migration In that case just rename the meta keys the other way around:

UPDATE wp_postmeta
SET meta_key = REPLACE(meta_key, 'qtranslate_', '_qts_') 
WHERE meta_key like 'qtranslate_%';

UPDATE wp_termmeta
SET meta_key = REPLACE(meta_key, 'qtranslate_', '_qts_') 
WHERE meta_key like 'qtranslate_%';

Attention: all data are lost if done twice in a row without restoring QTS data!

Let me know how it goes.

[herrvigg]

@spleen1981 let me know how the new version looks and I can merge it with an updated commit message.
After that I think we are finally ready for release 3.12.0.

[spleen1981]

Looks good!