Fix deprecated message appearing in web context with PHP 8.1

[driehle]

Using krumo with PHP 8.1 and strict types always gives a deprected message:

Deprecated: strtolower(): Passing null to parameter #1 ($string) of type string is deprecated in [...]/vendor/mmucklo/krumo/class.krumo.php on line 503

It appears that the @$d['class'] is problematic here, which results in null if not defined:

if (in_array($function, array("krumo","k","kd")) || (strToLower(@$d['class']) == 'krumo') || (is_callable($callback) && call_user_func($callback, $d))) {
    break;
}

This PR fixes the issue by checking the existence with isset($d['class']) first.

Would be happy, if @mmucklo could release a fixed version! :-)

[scottchiefbaker]

What triggers this error on PHP 8.1?

The fix seems innocuous enough, but I think we should document what's triggering the error. I do not, get any errors of this type on PHP 8.0.

[driehle]

The error only occurs with PHP 8.1 and strict types enabled. Furthermore, as the relevant code fragment is in the section of peparing the backtrace for web, the issue only occurs when using Krumo in a non-CLI SAPI. It does not happen in CLI (but there is another, different deprecation warning, I just found out...).

The following code is enough. Note that you need to call Krumo from within a function, as otherwise - if called from the main context - there will be no backtrace being iterated in line 503.

<?php

declare(strict_types=1);

require_once 'vendor/autoload.php';

$myFn = function() {
    Krumo::dump(null);
};

$myFn();

You can use the build-in webserver as follows to have a non-CLI SAPI:

php8.1 -S 0.0.0.0:8080 -d display_errors=on -d error_reporting=E_ALL test.php

This is what the error looks like when accessing http://localhost:8080/:

[driehle]

... comment about trim()...

➡️ Moved into #65

[scottchiefbaker]

The trim() should go in a separate PR. Probably makes more sense to do:

$out = var_export($i) ?? "";

Instead of casting to a string? I dunno, what do you think? If you get these two issues separated I'll work on landing them ASAP.

[driehle]

I have updated this PR accordingly and created a separate PR for the CLI issue.

[scottchiefbaker]

Per #65 we're going to bump the required PHP version to 7.0 which will give us null coalesce. If we do that I think we should modify this fix ever to use NC.

Line 503 should be something like:

$class = strtolower($d['class'] ?? "");

And the if should be changed to check the new $class variable. I think that will be cleaner and easier to read. What do you think?

[driehle]

Done

[scottchiefbaker]

Excellent!

[scottchiefbaker]

@driehle I have updated the next branch with the two fixes we just landed, and bumped the version 0.7.0. Are you able to test with that branch to make sure we're solid with PHP 8.1?

I don't have PHP 8.1 easily accessible to test with. If you test with it for a couple of days and things are solid I'll look at doing a new release here by the end of the week.