PR Summary

• Enhancement in HTML Page Rendering Process
  This update primarily refines the way we draw together elements to create the 'head' and 'body' of our website pages. It involves tweaking our coding instructions - specifically by adding '(string)$output' to the 'preg_replace' routines. These are the pieces of code that control how different parts of the page are combined and displayed to the user. This change brings improved efficiency in the page rendering process.

Output buffer(s) may also be empty (containing NULL),

In what scenario it will be null?

@rob006 I really don't know. I was testing older Yii.1 online app on PHP 8.2.3 to see how costy it would to to upgrade. Out of all traced issues there was the only one caused by framework (Yii 1.1.28) - on line 414 (method CClientScript::renderHead()). Casting to string fixed the issue. Then I noted same preg_match() expressions in renderBodyBegin() and renderBodyEnd() and added to PR to potentially fix those too. I am not going to investigate details why was buffer NULL on line 414, no time for that. Feel free to close this PR if you think it's not justified or wait till someone confirms.

These methods do not accept nulls according to phpdoc, so if we want to handle nulls here, we should update phpdoc too. But IMO it would be better to identify case when this is happening and ensure that output is string before we pass it to methods for output processing.

These methods do not accept nulls according to phpdoc.

Well, they are public methods with pointer argument :-) So technically anything can be passed in whatever the documentation says. CClientScript may also be extended and the method(s) modified. I agree it would be better to provide particular details how NULL was passed in, so if I have some time on hands I may look into that.

Closing the PR as the issue seems to be in user code, otherwise feel free to reopen.