How to Prepare your Neon Configs for PHP 8 and Make them More Readable

2021-02-08

"The OP neurons aligned in OD pattern suggest better space orientation empowered to MDS usage."

What is explicit text? A text that does not require Googling acronyms to understand it.

What is explicit code? A code that does not require documentation to understand.

Have you Met... Magic?

Could you guess what this line is? No Googling allowed! :)

services:
    - Aws\Client(['region'='western'])

• A factory or a service?
• Array of arguments or a single argument with an array?

What about this one?

services:
    -
        factory: App\Some\Factory([KEY=%value%])

• The array is an argument for the constructor of a factory?
• Or parameters to the factory method?
• The factory method... hm, probably create()?
• Is the KEY an env variable?
• Is %value% a parameter?

Apart WTF readability and principle of highest surprise, there is a new problem since PHP 8.

PHP 8 - Named Arguments and Optional Parameter Last

This code used to be valid in PHP 7.4:

function foo($optional = null, $require)
{
}

Since PHP 8, it is deprecated (see 3v4l.org).

The optional parameters must be after required parameters, like this:

-function foo($optional = null, $require)
+function foo($require, $optional = null)
 {
 }

Don't worry about PHP code, Rector got this case covered. But what about all the NEON configs? If we change PHP code, the configs will break because they depend on the parameter order.

What about these "named arguments"? That might save us, but first, we have to untie this NEON spaghetti knot.

1. Unwrap Inlined Services

First, we need to untie these class + array single lines:

 services:
-    - Aws\Client(['region'='western'])
+    -
+        class: Aws\Client
+        arguments:
+           - ['region'='western']

2. Use Named Arguments

Sometimes we have to look at the class constructor to be able to transform NEON correctly:

namespace Aws;

final class Client
{
    public function __construct(
        private array $configuration = [],
    ) {
        // ...
    }
}

We see the argument is an array and is named $configuration. Let's use "named argument" in our NEON too:

 services:
     -
         class: Aws\Client
         arguments:
-           - ['region'='western']
+           configuration: ['region'='western']

Now, what happens if we add a new required argument to the constructor? But we can't add it after the optional argument in PHP 8. It will result in the argument order change!

 namespace Aws;

 final class Client
 {
     public function __construct(
+        private SomeDependency $someDependency,
         private array $configuration = [],
     ) {
         // ...
     }
 }

The code will still work thanks to named arguments ✅

3. Unwrap Inlined Arrays

Inlined arrays are confusing the same way the inlined services are. Let's get rid of them too while we're at it:

 services:
     -
         class: Aws\Client
         arguments:
-            configuration: ['region'='western']
+            configuration:
+                region: 'western'

There is also {} syntax for composed arrays. We can improve it too:

 services:
     -
         class: App\SocialLogin
         arguments:
-            - { facebook: no, google: yes, twitter: no }
+            params:
+                facebook: no
+                google: yes
+                twitter: no

4. Remove Implicit Arguments

Do you use a ... syntax? That is a placeholder for "complete autowired service here":

services:
    -
         class: App\Search
         arguments:
             - ...
             - ...
             - 'keys'

With named arguments, this is no longer needed:

 services:
     -
          class: App\Search
          arguments:
-             - ...
-             - ...
-             - 'keys'
+             type: 'keys'

Also, the config became much more readable. Now we know that 'keys' was used for a type.

Although named arguments were in NEON for a while, now our codebase is more consistent. The PHP with native named arguments and deprecated optional arguments first make the code base more robust.

The same rule that applies in NEON now applies in PHP. One less "cool" syntax sugar cream to learn and more space to focus on what matters to you.

Happy coding!

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