[PHP-DEV] [RFC] Display Function Arguments in Errors

Mailing Lists php.internals
21

On Mar 30, 2026, at 11:40 AM, Calvin Buckley <calvin@cmpct.info> wrote:

On Mar 11, 2026, at 12:55 PM, Calvin Buckley <calvin@cmpct.info> wrote:

Hi internals,

Based on the feedback I had from my proposal for function arguments in
errors last week, I'd like to introduce an RFC for it. Please let me
know what you think and please raise any possible issues.

PHP: rfc:display_error_function_args

Regards,
Calvin

If I don't hear any additional feedback, I think I'll open this for
voting at the end of the week.

I've changed the name again to try to address everyone's concerns;
because of this, I'll delay the voting by a week, especially since
it's a holiday on when I had originally intended to do so anyways.
Feedback would be appreciated.

22

Hi

Am 2026-03-31 15:57, schrieb Calvin Buckley:

Tim, would this name be OK? I also have a preference towards a non-inverted name (it was more overhead to keep track of it), but I do see wanting it consistent.

I *prefer* consistency for discoverability, but I agree that “inverted” INIs are confusing. No strong opinion either way and definitely not a deal breaker for me.

Best regards
Tim Düsterhus

23

On Apr 2, 2026, at 11:25 AM, Matthew Weier O'Phinney <mweierophinney@gmail.com> wrote:

On Wed, Mar 11, 2026 at 10:56 AM Calvin Buckley <calvin@cmpct.info> wrote:
Based on the feedback I had from my proposal for function arguments in
errors last week, I'd like to introduce an RFC for it. Please let me
know what you think and please raise any possible issues.

PHP: rfc:display_error_function_args

Have you done any benchmarking on this? What is the performance impact when it is enabled versus disabled? That information will be useful if this passes so that users can understand not just the security impact of having this information reported in logs, but the performance impact.

--
Matthew Weier O'Phinney
mweierophinney@gmail.com
https://mwop.net/
he/him

FWIW, I actually did try running benchmark/benchmark.php. The difference is pretty much margin of error (somehow fewer instructions in some cases?), but I also don't expect to see much of any docrefs triggered in it either. For the sake of completeness:

Without:
{
    "Zend\/bench.php": {
        "instructions": "1979721332"
    },
    "Zend\/bench.php JIT": {
        "instructions": "589555739"
    },
    "Symfony Demo 2.2.3": {
        "instructions": "87285017"
    },
    "Symfony Demo 2.2.3 JIT": {
        "instructions": "90024058"
    },
    "Wordpress 6.2": {
        "instructions": "244605957"
    },
    "Wordpress 6.2 JIT": {
        "instructions": "211892436"
    }
}
With:
{
    "Zend\/bench.php": {
        "instructions": "1979721328"
    },
    "Zend\/bench.php JIT": {
        "instructions": "589555784"
    },
    "Symfony Demo 2.2.3": {
        "instructions": "87285011"
    },
    "Symfony Demo 2.2.3 JIT": {
        "instructions": "90023734"
    },
    "Wordpress 6.2": {
        "instructions": "244606014"
    },
    "Wordpress 6.2 JIT": {
        "instructions": "211892519"
    }
}

You can try it yourself with this patch (set error_include_args as needed):

diff --git a/benchmark/benchmark.php b/benchmark/benchmark.php
index 0c2ac4c6010..6377c3ceb37 100644
--- a/benchmark/benchmark.php
+++ b/benchmark/benchmark.php
@@ -79,7 +79,8 @@ function runWordpress(bool $jit): array {
     /* FIXME: It might be better to use a stable version of PHP for this command because we can't
      * easily alter the phar file */
     runPhpCommand([
- '-d error_reporting=0',
+ '-d error_reporting=22527',
+ '-d error_include_args=1',
         'wp-cli.phar',
         'core',
         'install',
@@ -122,6 +123,8 @@ function runValgrindPhpCgiCommand(
         '--',
         $phpCgi,
         '-T' . ($warmup ? $warmup . ',' : '') . $repeat,
+ '-d error_reporting=22527',
+ '-d error_include_args=1',
         '-d max_execution_time=0',
         '-d opcache.enable=1',
         '-d opcache.jit=' . ($jit ? 'tracing' : 'disable'),

I'm working on something that triggers a lot of docrefs in a hot loop, but I also don't know how interesting that would be seeing as if you're getting thousands of docref-triggered messages a second, your program probably has an issue.

24

On Apr 2, 2026, at 11:25 AM, Matthew Weier O'Phinney <mweierophinney@gmail.com> wrote:

On Wed, Mar 11, 2026 at 10:56 AM Calvin Buckley <calvin@cmpct.info> wrote:
Based on the feedback I had from my proposal for function arguments in
errors last week, I'd like to introduce an RFC for it. Please let me
know what you think and please raise any possible issues.

PHP: rfc:display_error_function_args

Have you done any benchmarking on this? What is the performance impact when it is enabled versus disabled? That information will be useful if this passes so that users can understand not just the security impact of having this information reported in logs, but the performance impact.

--
Matthew Weier O'Phinney
mweierophinney@gmail.com
https://mwop.net/
he/him

I've been doing a very stupid benchmark (let's call it Lhogstones):

<?php

/* -d error_include_args=X -d display_errors=0 -d error_log=/tmp/test */

$iter = isset($argv[1]) ? intval($argv[1]) : 10000;
$start = hrtime(true);
for ($i = 0; $i < $iter; $i++) {
        hex2bin("ABC"); /* or like unlink("/") for something that does more */
}
$end = hrtime(true);
$total_ns = $end - $start;
$total = $total_ns / 1_000_000_000;

echo "Finished $iter iterations in $total sec\n";

?>

On an M1 Pro:

Iterations With Without
10000 0.025276917 0.016741333
100000 0.189566666 0.123559584
1000000 1.798127917 1.146331917
10000000 18.1332335 11.267384125

There is an impact from turning it on, but my feeling is that it would be pretty minor. If your code has a lot of warnings/errors, then my feeling is that errors should be fixed before you can or should measure performance. Calling php_error_docref in a tight loop isn't really normal behaviour. So, while there is an impact, I also don't think it matters too much. If people think the impact *does* matter and is significant, then I could add a vote to separate the production vs. development INI value.

25

On Apr 2, 2026, at 3:39 PM, Calvin Buckley <calvin@cmpct.info> wrote:

I've changed the name again to try to address everyone's concerns;
because of this, I'll delay the voting by a week, especially since
it's a holiday on when I had originally intended to do so anyways.
Feedback would be appreciated.

I've updated the RFC again to put benchmarks for perf impact (as was
mentioned on the list); for the sake of a minor change cooldown period,
I'll give it another week to start voting and allow for discussion.