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Date: Fri, 17 Jun 2016 11:29:06 +0300
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To: PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Throwing an Error for require expressions in PHP7.x
From: lisachenko.it@gmail.com (Alexander Lisachenko)

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Nikita, Dmitry, ping. What do you think, shouldn't we replace all possible
places with Fatal Errors with correct throwing of Error exceptions?  In
this concrete case it's for "require" operator.

From what I can see Error will give us more control over the file loading
process and make it more atomic, because additional checks
if(file_exists($file) && is_readable($file)) generate extra stat commands,
they are slow and not reliable, because for highload projects, we can be in
the situation where "if" succeeded, but the "require" will fail because our
file was deleted immediately after check.

Code like this:
try {
    require $fileName;
} catch (Error $e) {
    echo "Oops, maybe deleted? " . $e;
}

is much more reliable than following, by using "include" instead of
"require". This was suggested in https://bugs.php.net/bug.php?id=72089:

if (file_exists($fileName) && is_readable($fileName)) {
    @include $fileName; // Silencing errors for the case of race-condition,
etc
}

Pay an attention, that we always need to put the silencing operator here to
prevent warnings, etc. This also hides all internal errors for parsing,
thanks to the PHP. And we can't easily detect the reason why include was
failed. Only possible way is to register error_handler and throw an
instance of ErrorException.

But if require will throw an Error, nothing will changed, because unhandled
Error will produce a Fatal Error, but all modern code will be able to
handle this situation.

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