[4.0] Error message for database name in installation

[bembelimen]

Steps to reproduce the issue

Start the installation and insert a database with an invalid character (like "-"). You get an error:
The database name is invalid. It must start with a letter, followed by alphanumeric characters..

Checking the code here https://github.com/joomla/joomla-cms/blob/4.0-dev/installation/src/Model/DatabaseModel.php#L183-L188 and here: https://github.com/joomla/joomla-cms/blob/4.0-dev/installation/src/Model/SetupModel.php#L320-L325 the regexp is: #^[a-zA-Z_][0-9a-zA-Z_$]*$# means, a underscore is allowed, too as first char. Perhaps the error message should be changed (e.g. https://github.com/joomla/joomla-cms/blob/4.0-dev/installation/language/en-GB/en-GB.ini#L62 )

The next question is: why is a normal dash not allowed?

[brianteeman]

Then the regex is wrong if it allows the _ and I will submit a pr for that

The dash is not allowed because it is not part of the specification from mysql - it may work but it is known to cause problems just as starting with a number may do

[brianteeman]

See #21583