Revert "Deprecate returning non-string values from a user output handler (#18932)" (#20455)

This partially reverts commit d8577d9, and
reverts parts of 07f1cfd.

Author: DanielEScherzer

UPGRADING

@@ -361,16 +361,10 @@ PHP 8.5 UPGRADE NOTES
 ========================================
 
 - Core:
-  . Returning a non-string from a user output handler is deprecated. The
-    deprecation warning will bypass the handler with the bad return to ensure
-    it is visible; if there are nested output handlers the next one will still
-    be used.
-    RFC: https://wiki.php.net/rfc/deprecations_php_8_4
   . Trying to produce output (e.g. with `echo`) within a user output handler
     is deprecated. The deprecation warning will bypass the handler producing the
     output to ensure it is visible; if there are nested output handlers the next
-    one will still be used. If a user output handler returns a non-string and
-    produces output, the warning about producing an output is emitted first.
+    one will still be used.
     RFC: https://wiki.php.net/rfc/deprecations_php_8_4
   . Non-canonical cast names (boolean), (integer), (double), and (binary) have
     been deprecated, use (bool), (int), (float), and (string) respectively.

main/output.c

@@ -956,7 +956,6 @@ static inline php_output_handler_status_t php_output_handler_op(php_output_handl
 		if (handler->flags & PHP_OUTPUT_HANDLER_USER) {
 			zval ob_args[2];
 			zval retval;
-			ZVAL_UNDEF(&retval);
 
 			/* ob_data */
 			ZVAL_STRINGL(&ob_args[0], handler->buffer.data, handler->buffer.used);
@@ -969,36 +968,20 @@ static inline php_output_handler_status_t php_output_handler_op(php_output_handl
 			handler->func.user->fci.retval = &retval;
 
 			if (SUCCESS == zend_call_function(&handler->func.user->fci, &handler->func.user->fcc) && Z_TYPE(retval) != IS_UNDEF) {
-				if (Z_TYPE(retval) != IS_STRING || handler->flags & PHP_OUTPUT_HANDLER_PRODUCED_OUTPUT) {
+				if (handler->flags & PHP_OUTPUT_HANDLER_PRODUCED_OUTPUT) {
 					// Make sure that we don't get lost in the current output buffer
 					// by disabling it
 					handler->flags |= PHP_OUTPUT_HANDLER_DISABLED;
-					// Make sure we keep a reference to the handler name in
-					// case
-					// * The handler produced output *and* returned a non-string
-					// * The first deprecation message causes the handler to
-					// be removed
-					zend_string *handler_name = handler->name;
-					zend_string_addref(handler_name);
 					if (handler->flags & PHP_OUTPUT_HANDLER_PRODUCED_OUTPUT) {
 						// The handler might not always produce output
 						handler->flags &= ~PHP_OUTPUT_HANDLER_PRODUCED_OUTPUT;
 						php_error_docref(
 							NULL,
 							E_DEPRECATED,
 							"Producing output from user output handler %s is deprecated",
-							ZSTR_VAL(handler_name)
-						);
-					}
-					if (Z_TYPE(retval) != IS_STRING) {
-						php_error_docref(
-							NULL,
-							E_DEPRECATED,
-							"Returning a non-string result from user output handler %s is deprecated",
-							ZSTR_VAL(handler_name)
+							ZSTR_VAL(handler->name)
 						);
 					}
-					zend_string_release(handler_name);
 
 					// Check if the handler is still in the list of handlers to
 					// determine if the PHP_OUTPUT_HANDLER_DISABLED flag can

tests/output/ob_start_basic_002.phpt

@@ -35,24 +35,19 @@ foreach ($callbacks as $callback) {
 }
 
 ?>
---EXPECTF--
+--EXPECT--
 --> Use callback 'return_empty_string':
 
 
 --> Use callback 'return_false':
-
-Deprecated: ob_end_flush(): Returning a non-string result from user output handler return_false is deprecated in %s on line %d
 My output.
 
 --> Use callback 'return_null':
 
-Deprecated: ob_end_flush(): Returning a non-string result from user output handler return_null is deprecated in %s on line %d
-
 
 --> Use callback 'return_string':
 I stole your output.
 
 --> Use callback 'return_zero':
-
-Deprecated: ob_end_flush(): Returning a non-string result from user output handler return_zero is deprecated in %s on line %d
 0
+