TYPO3 Core

This is still an issue with current trunk.
Since revision 3368 there are no fields of the type "blob" in table sys_templates anymore, but some "text" fields. And these are handled the same way by the function you mentioned:

case 'text':
case 'blob':
$value = substr($value,0,65536);
break;

After reading the MySQL Docs I think, that this is not fixable (at least not for TYPO3):
The maximum length for BLOB and TEXT is determined by the storage requirements. And the maximum size of a row in a MyISAM table is 65,535 bytes...
See http://dev.mysql.com/doc/refman/5.1/en/blob.html
http://dev.mysql.com/doc/refman/5.1/en/storage-requirements.html

Sitenote: When you try to save a text, which is too long, you get a message in the TYPO3 log module:
"These fields are not properly updated in database: (config) Probably value mismatch with fieldtype."

sorry, for reopen but in my opinion this is a really big problem.
Imagine, you have a website with lot of Conditions in a single sys_template, now you save a sys_template bigger than 64 KB, there is no Warning, no Information and the closing part of the Condition is cut away. in a really worst case you destroy the complete page, because your condition not work.

And the Message in the TYPO3 log Module is not very herlpful in this moment, the sys_template is saved and the cache is deleted.

Hmm, I see.
So there could be a check, if the datasize is to big (as there already is basically).
And if it is, there should be a (flash) message telling you about the problem.
The changed data should be displayed again (so that you don't loose anything).
But nothing should be saved and no cache deleted etc.

Can you provide a patch, Sven?

(Just as a workaround: If this error destroyed your page, I think you should be able to restore a working record (a template in your case) by reverting the change in the Belog module. And you obviously can use multiple templates to avoid this problem.)

hi Christopher,
Sorry, at the moment I don't have time for creating a patch, maybe at a later time.

and yes you're absolutely right with your workaround, especially with using multiple templates.
But sometimes if you got a TYPO3 System with a lot of legacy Code and no time for restructure ... In my case, it was a configuration for mailformplus, i killed some condtions with this bug and noticed it two or three days later.