What I Learned by Using thecodingmachine/safe

Safe replaces PHP native functions like file_get_contents with Safe\file_get_contents. Native functions return false on fail, but Safe throw exception instead.

"Good idea", I though, so I tried the package myself in Symplify and Rector.

I'm a big fan of instant personal experience over over-thinking. I didn't know if this package would be useful for me, so I tried it. My code is different from yours, so your experience might be different.

If you don't know, just try it.

This is my experience after 2 months of using Safe.

What I like 😍

What I didn't like 🙁

Function Autoloading Sucks in PHP

Function autoloading has much worse support than PSR-4 class autoloading. 3rd party tool is not ready for it, because it's very rare out in the wild. I personally don't know about any other function-based package.

I got stuck with building prefixed rector.phar for a week. See humbug/box#352 for more.

The API Changes Fast

In 0.11.1 there was added a new function, that caused ci to fail due to PHPStan rule that required to be used for all new functions. I added it to make CI pass. Then 0.11.2 it was removed - PHPStan passed, but function was removed and the code was broken.

BC breaks on patch versions caused Symplify packages to break down. This is allowed on the 0.x version (see Semver point 4), so it really resulted from my over-trust.

If this was the only issue, I could solve it with patch-lock in composer.json:

    "require": {
-       "thecodingmachine/safe": "^0.1.13"
+       "thecodingmachine/safe": "0.1.13"

But the combination of PHPStan rule CI fail or code fails forced to upgrade. Optional use of functions would be probably better, so I'd drop the PHPStan rule next time. But who would check the need for a Safe alternative? Chicken vs egg problem.

Memory Lock on Every Native Function

This leads me to memory lock problem.

When I add new native function array_filter, should I use the Safe version or not? I have to:

Before? I just typed array_filter

In the end, I feel it didn't solve any real problems for me, but add huge maintenance cost to my daily workflow. All this leads me to a conclusion:

A problem that doesn't exist, doesn't need a solution.

Hence, I removed the Safe package from my workflow.

What are Real Issues with Native Functions?


During the code cleanup, I found this:


throw new ShouldNotHappenException(
    sprintf('The is problem "%s"', $message, __METHOD__)

Can you spot the problem? See code on 3v4l.org.

It reports the $message, but the location of the error - __METHOD__ is skipped silently.

I'd expect Safe function to help me exactly with this because this is a real problem. The code doesn't work as supposed to.


Another real problem I have is realpath (it clear from the function name, right? :)):


$filePath = 'missing_file';

$realFilePath = realpath($filePath);

$fileInfo = new SplFileInfo($realFilePath);


Here PHP creates $fileInfo object, that might be a file... but is it?

See code on 3v4l.org.


David Grudl wrote about this issue many years ago. How to make preg_* really safe? He suggests the following:


function safeReplaceCallback($pattern, $callback, $subject)
    // verify callback
    if (! is_callable($callback)) {
        throw new Exception('Invalic callback.');

    // test on empty string
    if (preg_match($pattern, '') === false) { // compilation error?
        $error = error_get_last();
        throw new Exception($error['message']);

    // call PCRE
    $result = preg_replace_callback($pattern, $callback, $subject);

    // execution error?
    if ($result === null && preg_last_error()) {
        throw new Exception('Error during regular execution.', preg_last_error());

    return $result;


Is there a Better Way?

Have you read Hidden Gems of PHP Packages?

The point is simple - replace native functions with classes methods or objects that:

Here are few examples I use in my code:

-preg_match('#Hi (.*?)#', $content);
+Nette\Utils\Strings::match($somePath, '#Hi (.*?)#');
-// 50 % chance the file doesn't exist
-$fileInfo = new SplFileInfo($somePath);
+// throw exception on non-existing file
+$fileInfo = new Symplify\PackageBuilder\FileSystem\SmartFileInfo($somePath);

They also make PHPStan happy, because they return string, array... or throw an exception ✅

I love Nette\Utils and there are more packages like this in the PHP universe. Packages that use objects you can rely on.

And if not, just create your own object, that does the job you want like I did with Symplify\PackageBuilder\FileSystem\SmartFileInfo. If you know about Sprintf object, let me know :).

But remember: only solve problems that you already have.

Safe coding!

Do you learn from my contents or use open-souce packages like Rector every day?
Consider supporting it on GitHub Sponsors. I'd really appreciate it!