Conditionally require functions.php

[itafroma]

Composer unconditionally "autoloads" files using require (see composer/composer#3003): this causes problems with globally-installed dependencies or where the composer autoload happens to be called more than once (see guzzle/guzzle#676).

One solution is to guard against function redeclaration using function_exists(), something that both guzzle/promises and React do (see L4-7 in functions.php and reactphp/promise#25, respectively).

The solution guzzle/promises currently uses does not work: PHP will attempt to load the functions before the conditional is evaluated. I've opted for the React solution, which is to point to a shim functions_include.php file that checks for the existence of the first function within functions.php before including functions.php.

[itafroma]

Mostly-identical PRs for guzzle/guzzle and guzzle/promises were filed:

• Conditionally require functions.php guzzle#1146
• Fix conditionally requiring functions.php promises#6

[mtdowling]

I'd much rather this not be a new included file. It could just be a conditional at the top of the file and a return.

[itafroma]

@mtdowling That won't work: functions are interpreted before the conditional. This will return "hi!" for example:

print foo();

function foo() {
    print "hi!";
}

This will return a fatal:

function foo() {}

if (function_exists('foo')) {
    return;
}

function foo() {
    print "hi!";
}

[trowski]

The method below does work and keeps things in a single file.

function foo() {
    return "hi!";
}

if (!function_exists('foo')) {
    function foo() {
        return "goodbye!";
    }
}

echo foo(), "\n"; // Echoes hi!

So just wrap the function definitions in functions.php with if (!function_exists(__NAMESPACE__ . '\str')) { ... }.

[itafroma]

@mtdowling saw you merged the corresponding PRs for guzzle/promises and guzzle/guzzle: thanks! Is this PR good to go, or do you want to handle this one differently?

[mtdowling]

Yeah, this PR is fine. Thanks.

[magnetik]

Is there any plan to release a stable version with this fix anytime soon?

Thanks