How to 'undeclare' a custom function in a loop

Solution 1:

You can execute the files in another process, for example (assuming $testFunction is defined in the files), you could do something like this (assuming you are running on Linux):

foreach($fileList as $file) {
    // load code from the current file into a $code variable,
    // and append a call to the function held in the $testFunction variable
    $code = file_get_contents($file) . "\n" . '$testFunction();';

    // save this to a temporary file
    file_put_contents('/tmp/test-file.php', $code);

    // execute the test file in a separate php process,
    // storing the output in the $output variable for examination
    $output = shell_exec('php /tmp/test-file.php');

    // examine output as you wish
}

unlink('/tmp/test-file.php');

EDIT:

Since testFunction does not echo, and instead returns the output to be examined, we can simply modify the test file to echo testFunction();.

$code = file_get_contents($file) . "\n" . 'echo testFunction();'; // <- NOTE: the semi-colon after testFunction();

I noticed my original answer was lacking a semi-colon in the test file, which is probably where the error was coming from. What you can do to ensure it's correct is have this script generate the first test file and terminate early. You can then manually inspect the file for correctness and also use PHP to ensure it's parse-able, from the command line:

php -l /tmp/test-file.php

Note also there are more sophisticated ways you could check correctness of each test file, however I am trying to keep the answer concise, as that is starting to stray into a separate question.