Undefined offset 0 in \inc\cache.php

Hello there! I’m receiving this message in our logs:
[13-Aug-2020 11:54:30 America/New_York] PHP Notice: Undefined offset: 0 in D:\home\site\wwwroot\wp-content\plugins\wp-fastest-cache\inc\cache.php on line 865

Peaking at the cache.php file in your plugin, this is the function:

public function fix_pre_tag($content, $buffer){
			if(preg_match("/<pre[^\>]*>/i", $buffer)){
				preg_match_all("/<pre[^\>]*>((?!<\/pre>).)+<\/pre>/is", $buffer, $pre_buffer);
				preg_match_all("/<pre[^\>]*>((?!<\/pre>).)+<\/pre>/is", $content, $pre_content);
				if(isset($pre_content[0]) && isset($pre_content[0][0])){
					foreach ($pre_content[0] as $key => $value){
						/*
						location ~ / {
						    set $path /path/$1/index.html;
						}
						*/
						$pre_buffer[0][$key] = preg_replace('/\$(\d)/', '\\\$$1', $pre_buffer[0][$key]);
						$content = preg_replace("/".preg_quote($value, "/")."/", $pre_buffer[0][$key], $content);
					}
				}
			}
			return $content;
		}

And this is the line 865:
$pre_buffer[0][$key] = preg_replace('/\$(\d)/', '\\\$$1', $pre_buffer[0][$key]);

Since reading this article, would it make sense to change the if-statement from this:
if(isset($pre_content[0]) && isset($pre_content[0][0]))

to this?
if((isset($pre_content[0]) || array_key_exists(0,$pre_content)) && (isset($pre_content[0][0])) || array_key_exists(0,$pre_content[0])))

Because it seems odd to me that isset($pre_content[0]) would evaluate to true but then suddenly be an undefined offset within the foreach loop. But that article I linked above may explain why this is happening. Thank you!

—-

Actually, now that I look harder, I notice that the line being flagged is referencing the $pre_buffer array, not $pre_content, so maybe the if-statement should be this:
if(isset($pre_content[0]) && isset($pre_content[0][0]) && isset($pre_buffer[0]))

• This topic was modified 5 years, 9 months ago by Tessa Watkins.
• This topic was modified 5 years, 9 months ago by Tessa Watkins.
• This topic was modified 5 years, 9 months ago by Steven Stern (sterndata).