10 Cool Features You Get after switching from YAML to PHP Configs

2020-07-16

Do you care why this begun? Be sure to read Symfony issue:

The biggest advantage is IDE auto-completion out of the box,
and one XML/YAML language less to learn.

There are the cool features I've observed from migration of 50+ YAML configs to PHP:

1. Absolute Paths over Random Paths

In configs, we often define paths to files or directories. Could you tell me what exact path this is?

parameters:
    paths:
        - 'src'

• relative to the config location?
• absolute to %kernel.projectDir%?
• absolute to %cwd%?
• what will warn us if we move the config?

We don't know. It depends on the internal tool implementation and luck.

Now the same config in PHP:

Pretty clear, right?

2. We Can See Deprecated Classes in PHPStorm

The YAML config will not show you, if class was deprecated:

PHPStorm will cross the deprecated class and prepare you better for the future:

3. Missing Classes in Parameters

In YAML, everything is a string by default, so YAML doesn't know that you mean a class.

PHPStorm shows that pretty clearly:

4. IDE Autocomplete Just Works

Do you recall YAML struggle, when you want to register a service?

In PHP config you can forget it and just type:

Even with typos like "Application" ;)

5. How was that calls Syntax?

Do you remember how to set a call on the service setup?

services:
    SomeClass:
        calls:
            # what now?

No, don't Google it! Try from the top of your head.

An intuitive way would be to use the same syntax as properties/arguments:

services:
    SomeClass:
        calls:
            'setValue': [1]

No :( then we have to Google it...

In PHP we can use intuitive approach and see what IDE tells us:

6. No More Magic YAML syntax for Constants

In YAML everything is a string:

parameters:
    line_ending: PHP_EOL

Is that PHP_EOL constant as we know it? No, it's "PHP_EOL" string.

How can we specify a string that is a constant? (Feels weird for my brain just writing this sentence.)

Symfony 3.2 introduced special prefix: !php/const

parameters:
    line_ending: !php/const PHP_EOL

Pretty crazy, right?

How does PHP solve this?

use  Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;

return function (ContainerConfigurator $containerConfigurator): void {
    $parameters = $containerConfigurator->parameters();

    $parameters->set('line_ending', PHP_EOL);
};

It just works, no headache!

7. One Way to Add Arguments

These 2 files will produce the same configuration:

services:
    SomeService:
        # silent "arguments" key is omitted
        $key: value

services:
    SomeService:
        arguments:
            $key: value
            # or was it this?
            # key: value

In PHP this is just 1 clear way:

use Symfony\Component\Console\Application;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;

return function (ContainerConfigurator $containerConfigurator): void {
    $services = $containerConfigurator->services();

    $services->set(Application::class)
        ->arg('key', 'value');
};

8. No More Magic Tags Without Name

For tags, these 2 files produce the same output:

services:
    SomeService:
        tags:
            - kernel.event_subscriber
            # how do we extend this later?

services:
    SomeService:
        tags:
            - { name: 'kernel.event_subscriber' }

In PHP, there is just 1 way for both:

9. ECS, Rector & PHPStan watches your Config Now

This feature is my favorite by far because it finally opens the door for next-level automation.

YAML doesn't have any static analyzer or instant upgrade tool. This makes the upgrade of Symfony projects double the work - in PHP, in YAML.

Since *.php is PHP code, all the powerful CI tools have access to it.

Fewer bugs, effortless changes, less upgrade work, new PHPStan rules, more fun coding.

10. Constants over Strings 🎉

Last but not least. You've probably noticed I hate typos. I'm so used to tool watching my back, that I type much faster than my fingers can. Then I run the tools and code works (usually).

If you give me a choice of "string" or CONSTANT, 10 of 10 I pick the CONSTANT (unless the string is "really sexy and smart, verified").

We don't have such a solid choice in YAML. If we want to use a parameter used elsewhere, we need to trust name is somehow validated (it isn't, because exception will tell you anyway).

For example, how do you ignore files in ECS?

parameters:
    excluded_files:
    # or
    excluded_path:
    # or
    excluded_paths:

None of them :(. It's exclude_files! It's painful to look for such bugs because you need to analyze the whole project every time the config is changed.

In PHP, we can do this:

• Does the constant name change in the future? Rector handles it
• Is the constant missing? PHPStan reports it

🚀🚀🚀

Start Today, Time passes Anyway

Do you need more real-life examples to try it yourself? Learn from merged pull-requests:

• bolt/core migration of ecs.yaml to ecs.php
• the smallest migration of 1 file
• symlify/easy-coding-standard of 20 sets
• issue that lists finished YAML to PHP migrations

And of course, don't do it manually. Use automated tool - symplify/config-transformer - handles YAML/XML to PHP/YAML.

Happy coding!

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