[5.0] Remove utf8mb4 conversion

[richard67]

Pull Request for Issue # .

Summary of Changes

This pull request (PR) removes all code related to the utf8mb4 conversion.

Joomla 4.0 and later require a minimum database version for MySQL or MariaDB which supports utf8mb4 and so would not run on databases which do not support it.

But as a result of a sever migration when updating from 3.10 to 4.x, it could still be that the database tables of the core haven't been converted to utf8mb4 yet, so the update to 4.x had to make that conversion.

Given that people have to be on a Joomla 4.x before they can update to 5.0, so updates from 3.10.x to 5.0 will not be possible, it is granted that the database has been converted in past when they had updated from 3.10.x to 4.y.

So for updating to 5.0 all code and SQL scripts related to that conversion are obsolete.

Testing Instructions

The tests make only sense with MySQL or MariaDB databases but not with PostgreSQL.

Update any Joomla 4.x version to the custom update URL or the update package which have been built by drone for this PR and make sure that the update works.

After that, make sure that the database checker ("System -> Maintenance -> Database", i.e. administrator/index.php?option=com_installer&view=database) still works.

Actual result BEFORE applying this Pull Request

Obsolete, unused code and SQL scripts for utf8mb4 conversion of MySQL or MariaDB databases.

Expected result AFTER applying this Pull Request

No obsolete, unused code and SQL scripts for utf8mb4 conversion of MySQL or MariaDB databases.

Updating from any Joomla 4.x version works as well as without this PR.

The database checker works as well as without this PR.

Documentation Changes Required

None.

[brianteeman]

This will mean that any j3 site will have to be updated via j4 - is that the intention?

[richard67]

This will mean that any j3 site will have to be updated via j4 - is that the intention?

@brianteeman That's what I assume, and as far as I know that's the plan.

@HLeithner @nibra please correct me if that is wrong.

[brianteeman]

Just wanted it to be clear. In the absence of any road map its hard to know what the plans are

[HLeithner]

Yes there will me no direct update path between 3 and 5

[richard67]

In the absence of any road map its hard to know what the plans are

@brianteeman As long as we are not on the road to nowhere ... or the highway to hell ... 😄

[HLeithner]

Depending on the progress we will see if a upgrade to 4.4 is needed (like 3.10) or direct update from any 4.x version is possible.

[richard67]

Depending on the progress we will see if a upgrade to 4.4 is needed (like 3.10) or direct update from any 4.x version is possible.

@HLeithner This depends mainly on if we want to keep the old 4.x update SQL scripts - then we can update from any J4 version - or if we throw them away like we threw away the 3.x update SQL scripts in J4 - then we have to come from the latest J4 version.

[richard67]

@HLeithner P.S.: To throw old update SQL scripts away has the advantage to be more flexible with new update SQL scripts regarding the database checker, because that does not understand when you modify the same thing again in the history of update SQL scripts. E.g. you cannot remove an index and later add it back with the same name, or remove a column and later add it back to the same table with the same same, such things, without the database checker showing false errors which cannot be fixed.

[HLeithner]

@HLeithner P.S.: To throw old update SQL scripts away has the advantage to be more flexible with new update SQL scripts regarding the database checker, because that does not understand when you modify the same thing again in the history of update SQL scripts. E.g. you cannot remove an index and later add it back with the same name, or remove a column and later add it back to the same table with the same same, such things, without the database checker showing false errors which cannot be fixed.

having a better database management system would also be great^^

[Abernyte-Git]

I have tested this item ✅ successfully on aa13e59

Works as expected.

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[wilsonge]

We should probably remove the #__utf8_conversion table as part of this PR in this case

[richard67]

We should probably remove the #__utf8_conversion table as part of this PR in this case

@wilsonge The table is already removed (dropped) after a successful conversion here: https://github.com/joomla/joomla-cms/blob/4.2-dev/administrator/components/com_admin/script.php#L7969-L7974

If the table still exists for some reason in 4.x, the database checker will show that as an error, see https://github.com/joomla/joomla-cms/blob/4.2-dev/libraries/src/Schema/ChangeSet.php#L97-L124 .

Using the "Fix" button will then run the conversion, see https://github.com/joomla/joomla-cms/blob/4.2-dev/administrator/components/com_installer/src/Model/DatabaseModel.php#L305 .

So at the end the table does not exist anymore, or the conversion has failed.

I could add a 5.0.0 update SQL script with a DROP TABLE IF EXISTS ... for MySQL in addition to be sure the table is deleted in any case.

But is that really necessary? If you say yes, I will add the script.

[RickR2H]

I have tested this item ✅ successfully on aa13e59

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[richard67]

RTC (seems nobody else is here who checks if a PR has 2 tests)

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[HLeithner]

thanks

[zero-24]

Joomla 4.0 and later require a minimum database version for MySQL or MariaDB which supports utf8mb4 and so would not run on databases which do not support it.

Just FYI this should be the case but the minimum database version is not enforced you can still install and manually update. The Core Updater checks the versions but the CMS itself does not. And we can not enforce this before 5.0 as that would be an unexpected major break while installing an update.