Automated type checking of code samples in docs

[SamMousa]

          True. I don't know how to do that however.

Originally posted by @greg0ire in #11492 (comment)

I might be able to help set this up.
Started on a proof of concept extractor already.

<?php

$lines = file(__DIR__ . '/en/tutorials/composite-primary-keys.rst', FILE_IGNORE_NEW_LINES);

$indent = null;
$blockCounter = 0;
$block = [];
foreach($lines as $i => $line) {
    // Check if this is the start of a php block.
    if ($indent === null && preg_match('/^(\s*)\<\?php/', $line, $matches)) {
        echo "Start PHP block\n";
        $indent = strlen($matches[1]);
        $block[] = "<?php //Extracted from line $i\n";
    } elseif ($indent !== null && preg_match("/^\s{{$indent}}(.*)|^()$/", $line, $matches)) {
        $block[] = ($matches[1] ?? ''); // . "\t\t\t\t# Extracted from line $i";
    } elseif ($indent !== null) {
        $indent = null;
        print_r($block);
        file_put_contents("/tmp/check/block{$blockCounter}.php", implode("\n", $block));
        $blockCounter++;
        $block = [];

    }

}

The idea is simple:

• Parse each .rst file crudely extracting PHP code blocks.
• Add missing imports automatically (or decide that we want copy paste friendly docs and just add missing imports to the examples)
• Run phpstan to analyse the code.

The extractor above also adds a comment to know where we got it from:

<?php //Extracted from line 112

namespace VehicleCatalogue\Model;

// $em is the EntityManager

$car = new Car("Audi A8", 2010);
$em->persist($car);
$em->flush();

I'll look into creating a github action that just does this for all RST files in a directory.

[greg0ire]

Add missing imports automatically (or decide that we want copy paste friendly docs and just add missing imports to the examples)

I think we should have copy/paste friendly docs

[SamMousa]

I'm ready to push the PR, what branch should I target?

[greg0ire]

2.19.x please.