Description

In PHP 8.5 the --ini CLI option was changed from no_argument to optional_argument to support the new --ini=diff subcommand. As a side effect, --ini (without a value) now fails with Unknown argument for --ini whenever it is preceded on the command line by another option that takes a required argument.

Reproducer (PHP 8.5):

$ php --ini                       # OK
$ php -n --ini                    # OK   (-n takes no argument)
$ php -c /etc/php.ini --ini       # FAIL: Unknown argument for --ini
$ php -d foo=bar --ini            # FAIL: Unknown argument for --ini
$ php --ini -c /etc/php.ini       # OK   (workaround: reorder)

The same commands work correctly in PHP 8.4 and earlier.

Expected behavior:

--ini without a value should be treated identically regardless of its position on the command line, equivalent to --ini=.

Root cause:

In main/getopt.c, php_getopt() does not reset *optarg between calls. When a long option is declared with need_param == 2 (optional) and is supplied without =value, the function falls through without assigning *optarg, leaving it pointing at the value consumed by the previous option (e.g. the path passed to -c, or the assignment passed to -d). The CLI SAPI then interprets that stale value as the --ini subcommand, fails to match it against "" or "diff", and emits the error.

The bug existed before 8.5 but was never observable because no long option used optional_argument. The introduction of --ini=diff (and the corresponding flip of --ini to optional_argument) exposed it.

Affected versions: 8.5.0 and later (any build with --ini=diff support).

Proposed Patch

The simplest and most defensive fix is to clear *optarg at the top of php_getopt() so that callers never observe a stale pointer from a previous invocation, regardless of which code path is taken later.

--- main/getopt.c.orig	2026-03-10 19:15:23.000000000 -0400
+++ main/getopt.c	2026-04-24 06:11:15.038033405 -0400
@@ -59,6 +59,7 @@
 	static char **prev_optarg = NULL;
 
 	php_optidx = -1;
+	*optarg = NULL;
 
 	if(prev_optarg && prev_optarg != optarg) {
 		/* reset the state */

PHP Version

PHP 8.5.4 (cli) (built: Apr 24 2026 07:24:54) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.5.4, Copyright (c) Zend Technologies
    with Zend OPcache v8.5.4, Copyright (c), by Zend Technologies

Operating System

Debian 12.13