Don't fetch eager-loaded has_many or many_many unless we've validated
that the relation IS actually a has_many or many_many relation.
Also clear eager-loaded relations when flushing the record.
Includes making sure toArray() uses the correct iteration logic,
and cloning resets the eagerloaded data for the new clone.
Previously, a second iteration would add every relation item to the
relation list a second time - so with each iteration your relation list
count doubled (though it was the same records time and again).
* FIX PHP 8.1 support in MySQLiConnector::query errors
The default error reporting mode in PHP 8.1 has changed from using
errors reported on the connection handle to throwing
mysqli_sql_exception. query() makes no allowance for this, and
functions up the call stack expect to catch
Silverstripe\ORM\Connect\DatabaseException instead - resulting in the
MySQLi exception going all the way up to halt the system.
We can use a try, catch, and finally to retain backwards compatibility,
no matter which setting (e.g. PHP version default) someone has enabled.
* Move MySQLConnector test skip call into setUp()
As review feedback; marking the test as skipped in a private function
obfuscated where the call was happening and made it harder to skimread
the tests. Moving this into a setUp function makes it obvious the check
is run before each test case, and skipped if necessary.
It is hard to work with the current structure - having each relation
type in its own method makes it way easier to see where my concerns
start and end with a given relation.
This also reduces the chance of variable bleed-over, where the value in
a variable in the first loop (in the same or other relation type) could
bleed into the next iteration of the loop.
Using a table name in sort() is not allowed in CMS 5. We could use
orderBy() here but member is the table it will sort on by default anyway
so there's no need.
Also added unit tests, which should have caught this ages ago.
