[BUGFIX] Prevent Twig from swallowing whitespace between inline tags

[linawolf]

resolves #922

I can only solve this by outputting &32; which equals a space. @wouterj is there any solution to force Twig to preserve a real space char?

[wouterj]

I can only solve this by outputting &32; which equals a space. @wouterj is there any solution to force Twig to preserve a real space char?

It does not appear to be Twig who swallows the whitespace. If I try out this minimal example, the output is · (i.e. Twig renders it as a single space):

<?php

require_once 'vendor/autoload.php';

$loader = new \Twig\Loader\ArrayLoader([
    'test.twig' => '{{- value -}}',
]);
$twig = new \Twig\Environment($loader);

/** Small function to make whitespace visible */
function show_whitespace(string $text) {
    return preg_replace(['/\v/', '/\h/'], ["¶\n", '·'], $text);
}

echo show_whitespace(
  $twig->render('test.twig', ['value' => ' '])
);

I've always been a bit confused by how whitespace is handled in this project, the need for {% apply spaceless %} in some templates is also strange to me. I think we must identify which part of the NodeRenderer process is responsible for swallowing the whitespace.

[linawolf]

I can render any sign but a space. I have no idea how twig works. Chatgbt told me it tries to get rid of superfluous spaces...

[linawolf]

applyspaceless is needed in inline templates, because our id adds some such as an empty line at the end of each document. These would then get output, however bold: then becomes bold :

[wouterj]

I'll find some time this weekend to see if I can find the troubling spot using the test case you added in this PR.

[wouterj]

I've tracked down this issue to be a result of using the spaceless filter in paragraph.html.twig. I've refactored whitespace control to avoid using spaceless anywhere and taken your test from here in #944. We can close this as being replaced by the new PR.