$config['flood_cache'] undefined by default, causes error on config page in PHP 8.x

[discomrade]

The flood_cache config was introduced in this 2013 commit: f309e4037c and has been unchanged since.

I believe was is left commented and undefined intentionally. This is the only place it is used, where it changes code behavior if it has been set:

vichan/inc/filters.php

Lines 191 to 198 in fa198e2

	// Determine how long we need to keep a cache of posts for flood prevention. Unfortunately, it is not
	// aware of flood filters in other board configurations. You can solve this problem by settings the
	// config variable $config['flood_cache'] (seconds).
	if (isset($config['flood_cache'])) {
	$max_time = &$config['flood_cache'];
	} else {
	$max_time = 0;

However, newer PHP versions will raise an error if this config option is undefined, because this line doesn't check if the value exists before assigning it:

vichan/inc/mod/pages.php

Line 2495 in 70222e8

$c = @$config[$var['name']];

I'd like a second opinion on the best way to solve this.

• Is it valid to have an unset config variable and just check before use?
• Should it have a default value of 0 [disabled] to avoid creating a second config variable?

[ctrlcctrlv]

if this is now invalid you'll want to change its behavior yes. e.g. you can set it by default to -1.

[perdedora]

You can fix using:

$c = array_key_exists($var['name'], $config) ? $config[$var['name']] : null;

[discomrade]

You can fix using:

$c = array_key_exists($var['name'], $config) ? $config[$var['name']] : null;

I was thinking of doing a check similar to that, although it may be more useful to keep it how it is and have the code throw an error when it's trying to read a config key which doesn't exist. flood_cache is the only one, I think the config is the issue rather than the reader.

I think a designated disable value of -1 is the right way to do this

[ctrlcctrlv]

I suggested -1 because it's a horrible code smell to have config keys which cause different behavior when set vs unset, all config keys should be required to have some value. E.g. in Rust most of the time configuration is a struct so removing keys isn't even possible.

Also I really think my role with this project is just teaching people how to code better these days lol. So I just always suggest the best thing to do not necessarily easiest.