[TYPO3-core] RFC #8279: Bug: Sorting in fields of type "group", "MM=1" and "multiple=1" is not preserved

[Ingmar Schlecht]

Thanks for committing, I will now package the RCs.

cheers
Ingmar

Ernesto Baschny [cron IT] schrieb:
> Hi,
> 
> committed to TYPO3_4-1 (rev. 3768).
> 
> Cheers,
> Ernesto
> 
> Ernesto Baschny [cron IT] wrote: on 28.04.2008 14:56:
> 
>> Type: Bugfix
>>
>> Bugtracker references: http://bugs.typo3.org/view.php?id=8279
>>
>> ChangeSet reference for the fix by Kasper in TYPO3_4-2: 
>> http://code.typo3.org/v4/changeset/3002
>>
>> Branches: TYPO3_4-1
>>
>> Problem:
>> If I have a field defined like:
>>
>>        'mitglieder_ag' => array(
>>            'exclude' => 1,
>>            'label' => 
>> 'LLL:EXT:cronmm_ratsinfo/locallang_db.xml:tx_cronmmratsinfo_gremium.mitglieder_ag', 
>>
>>            'config' => array(
>>                'type' => 'group',
>>                'internal_type' => 'db',
>>                'allowed' => 'tx_cronmmratsinfo_ausschussgemeinschaft',
>>                'size' => 20,
>>                'minitems' => 0,
>>                'maxitems' => 100,
>>                'multiple' => 1,
>>                'selectedListStyle' => 'width:100px',
>>                'MM' => 'tx_cronmmratsinfo_gremium_mitglieder_ag_mm',
>>            )
>>        ),
>>
>> that is with "MM=xxx" and "multiple=1", I am able to have a list where 
>> the same record occurs multiple times, e.g:
>>
>> uid_foreign=45, sorting=1
>> uid_foreign=44, sorting=2
>> uid_foreign=44, sorting=3
>>
>> After moving the entry 45 down one item (to get the list "44, 45, 
>> 44"), and I save the record, I end up with the following list:
>>
>> 45, sorting = 1
>> 44, sorting = 3
>> 44, sorting = 3
>>
>> So not the desired sorting (sorting=3 twice). To sum up, I cannot 
>> separate the same uids: they will end up always being sorted in a 
>> "block".
>>
>>
>> Problem:
>> The problem comes from t3lib_loaddbgroup::writeMM(), which cannot 
>> handle "multiple=1".
>>
>> Imagine $oldMMs: 45, 44, 44 (the old order)
>> the new $this->itemArray in t3lib_loaddbgroup::writeMM() is: 44, 45, 
>> 44 (the desired new order)
>>
>> In t3lib_loaddbgroup::writeMM() TYPO3 will execute the following UPDATEs:
>>
>> UPDATE tx_cronmmratsinfo_gremium_mitglieder_ag_mm SET sorting = 1 
>> WHERE uid_local=1026 AND uid_foreign=44
>> UPDATE tx_cronmmratsinfo_gremium_mitglieder_ag_mm SET sorting = 2 
>> WHERE uid_local=1026 AND uid_foreign=45
>> UPDATE tx_cronmmratsinfo_gremium_mitglieder_ag_mm SET sorting = 3 
>> WHERE uid_local=1026 AND uid_foreign=44
>>
>> Notice that the last UPDATE will override what the first one did, so 
>> that we end up with the MM-table containing:
>>
>> 45, sorting = 2
>> 44, sorting = 3
>> 44, sorting = 3
>>
>> and we would expect:
>>
>> 44, sorting = 1
>> 45, sorting = 2
>> 44, sorting = 3
>>
>>
>> Solution:
>> In case of multiple=1, delete all records before we start and just 
>> write the new ones in the order they come in (with INSERT). Attached 
>> patch does that.
>>
>>
>> Note:
>> The problem is not present in TYPO3 4.2, because of this change done 
>> by Kasper in January: http://code.typo3.org/v4/changeset/3002. The 
>> solution here was to add a "uid" field for every MM table that needs 
>> "multiple=1", to be able to identify each record uniquely even if they 
>> contain the same uid_local/uid_foreign combination. I would like to 
>> fix the bug in 4.1 like suggested above, because else we would have to 
>> backport a new feature from 4.2 (new TCA setting "MM_hasUidField") to 
>> 4.1.
>>
>> BTW that new feature (see Kasper's ChangeLog) hasn't been documented 
>> and is not listed in 
>> http://wiki.typo3.org/index.php/Pending_Documentation#doc_core_api. 
>> Should I add it there?
>>
>> Cheers,
>> Ernesto
>>


-- 
Ingmar Schlecht
TYPO3 Association Active Member