ext/finfo: Deprecate the parameter for finfo_buffer() (php#19378)

RFC: https://wiki.php.net/rfc/deprecations_php_8_5#deprecate_the_context_parameter_for_finfo_buffer

Author: Girgias

ext/fileinfo/fileinfo.c

@@ -343,6 +343,13 @@ PHP_FUNCTION(finfo_buffer)
 		RETURN_THROWS();
 	}
 
+	if (ZEND_NUM_ARGS() == 4 || (hasThis() && ZEND_NUM_ARGS() == 3)) {
+		php_error_docref(NULL, E_DEPRECATED, "The $context parameter has no effect for finfo_buffer()");
+		if (UNEXPECTED(EG(exception))) {
+			RETURN_THROWS();
+		}
+	}
+
 	if (!Z_FINFO_P(self)->magic) {
 		zend_throw_error(NULL, "Invalid finfo object");
 		RETURN_THROWS();

ext/fileinfo/tests/finfo_buffer_deprecated_context_param.phpt

@@ -0,0 +1,20 @@
+--TEST--
+finfo_buffer() deprecated $context param
+--EXTENSIONS--
+fileinfo
+--FILE--
+<?php
+
+$finfo = finfo_open();
+$buffer = "Regular string here";
+
+var_dump(finfo_buffer($finfo, $buffer, FILEINFO_NONE, null));
+var_dump($finfo->buffer($buffer, FILEINFO_NONE, null));
+
+?>
+--EXPECTF--
+Deprecated: finfo_buffer(): The $context parameter has no effect for finfo_buffer() in %s on line %d
+string(36) "ASCII text, with no line terminators"
+
+Deprecated: finfo::buffer(): The $context parameter has no effect for finfo_buffer() in %s on line %d
+string(36) "ASCII text, with no line terminators"