TYPO3 Core

I could not duplicate this with 4.5.16, could you please give some more information about your environment (OS, PHP version).

I'm not sure if this is really related to #33580.
Looking at the code, the result you described could only occur, if substr($table, ...) would return an empty string.
But according to the PHP documentation this can never happen. Any error would return FALSE and that would be visible in the output.

The problem is the substr() function of PHP:

Using PHP 5.3 the code

var_dump(substr('test', -4));
var_dump(substr('test', -5));

string(4) "test" 
string(4) "test"

string(4) "test" 
bool(false)

The PHP documentation [http://php.net/manual/en/function.substr.php] states for the start parameter

If string is less than or equal to start characters long, FALSE will be returned. 

In the Install Tool the start parameter for substr() is calculated by

$deletedPrefixLength - self::MYSQL_MAXIMUM_FIELD_WIDTH

PHP 5.2 is officially supported for 4.5 and the problem was not there until 4.5.16, so this must be fixed (and should also be taken into account if used similarly somewhere else).

Yes that's exactly what I was referring to, but I still have no clue, why your screenshot doesn't show the FALSE in the output of the Installer.
I'll provide a patch, once we're able to explain why this FALSE is not shown.

A string concatenation of a string with boolean FALSE results only in the string: "zzz_deleted_".FALSE == "zzz_deleted_". To be compatible with PHP 5.2 the start parameter of substr() must not be smaller than -(strlen($table)) - something like

substr($table, max($deletedPrefixLength - self::MYSQL_MAXIMUM_FIELD_WIDTH, strlen($table) * -1 ))

At least TYPO3 4.5 should be solved, as it's minimum required PHP version is 5.2.0.

TYPO3 4.7 and later require PHP 5.3, so it should be ok. Thanks for analysing this Jigal.

This bugfix would have made sense to fix two years ago. It's still bad since 5.2 is officially supported but for me its ok to reject it. We have several 4.5 installations but none of them on 5.2. Even debian squeeze (with lts still supported) has 5.3.3-7 on board, only with lenny (not supported since 2/2012) you have 5.2.

"Enterprise CMS"-wise it should still be fixed - priority or not - the backup function of tables is broken.