Return a renderable array instead of a GeneratedLink in template_preprocess_file_link()

This issue should surely be addressed soon because Drupal::l() is deprecated.

as per deprecated notice the replacement for Drupal::l() would be:

Link::fromTextAndUrl($link_text, Url::fromUri($url, $options));

But i would suppose the patch provided by @geoffray would also suit the deprecation notice.

This is a small, logical, and straightforward change, which shouldn't break anything for anybody (except possibly implementations of the file_link preprocessor that are specifically expecting to see the GeneratedLink object, and I can't really imagine what they could be usefully accomplishing with it), and is very useful to anyone who needs to modify that link for some reason. The attached patch worked well for me on a Drupal 8.6 installation.

Bumping to Major because of the deprecation issue, since D9 is theoretically less than a year away; apologies if that's inappropriate (the priority documentation doesn't really mention deprecation issues), but this has been sitting back-burner for a while and it seems like an easy win to me.

Re-rolling against 8.8. Seems somebody already addressed the deprecation issue by using Link::fromTextAndUrl, but I believe it would still be more appropriate to return a render array here.

Yes, it seems this has been addressed very recently with this issue: https://www.drupal.org/node/3047801

So maybe this issue could be closed as duplicate.

#10 The problem described in the issue summary still applies: the generated link cannot be easily preprocessed or altered by themes.

+++ b/core/modules/file/file.module
@@ -1506,7 +1506,11 @@ function template_preprocess_file_link(&$variables) {
-  $variables['link'] = Link::fromTextAndUrl($link_text, Url::fromUri($url, $options))->toString();

Let's go with toRenderable() instead of toString() for the smallest possible change.

Yes, the problem still applies. I've overlooked the "toString()" call they put in with https://www.drupal.org/node/3047801.

Here comes the patch with toRenderable() which will result exactly in what is provided by the previous two patches.

But it seems even not to be necessary to use toRenderable() at all here, since Twig can handle the Link object too.

#12 Looks good to me. Typically Drupal core returns renderable arrays instead of class objects, so let's go with toRenderable() in line with the issue summary.

Committed 6bae96a and pushed to 8.8.x. Thanks!

Added and published a change record https://www.drupal.org/node/3074716