Update development.services.yml to include twig debug by default

Added a patch regarding this issue
Please review

The last one failed so added this new patch

Patch #4 applied successfully. Moving the issue to RTBC.

Adding screenshot.

RE #8, I would recommend not editing `.patch` files directly.

To add on to a patch, take a look at the interdiff documentation page on how to revise between versions: https://www.drupal.org/docs/develop/git/using-git-to-contribute-to-drupa... . For a complete summary of the process (including applying a patch. adding onto a patch, etc), please see: https://www.drupal.org/docs/develop/git/using-git-to-contribute-to-drupal

That being said, we probably should be using the GitLab fork + MR for ease-of-use and easier contributions.

Marking back to NW for the test fail in #4, which I don't think was checked (or fixed) in #8 or others.

The tests ran when you marked it Ready, a slight delay maybe. All good now!

Something else went wrong in that test run, but the main failure was Drupal\Tests\ComposerIntegrationTest which compares several specific files after a composer installation.
The key is to also change assets/scaffold/files/development.services.yml so that they match.

Back to NR. Failure was for patch file, and we're now using the MR. Also hidden patch #5 to make that a bit more clear.

Marking NW on this comment in default.services.yml

    # Twig cache:
    #
    # By default, Twig templates will be compiled and stored in the filesystem
    # to increase performance. Disabling the Twig cache will recompile the
    # templates from source each time they are used. In most cases the
    # auto_reload setting above should be enabled rather than disabling the
    # Twig cache.
    #
    # Disabling the Twig cache is not recommended in production environments.
    # @default true
    cache: true

Should we be setting cache: false over auto_reload: true? I normally do what is in the proposal. But maybe it's better to do what the docs actually recommend.

Assigning to myself to review.

Just a few typo fixes in the IS.

I think this would be a nice improvement for DX. God knows how many times I've forgotten to exclude development.services.yml from scaffolding so that its contents got reset by drupal/core-composer-scaffold and I had to enable twig debug again.

Should the include of development.services.yml in 'container_yamls' in example.settings.local.php then be commented out by default? To prevent unexperienced users from enabling twig debug on their live sites? Or alternatively we could leave it as is but add a warning that production sites should comment out the line?

This issue is being reviewed by the kind folks in Slack, #need-reveiw-queue. We are working to keep the size of Needs Review queue [2700+ issues] to around 200

Believe this may have missed the boat for 10.0 but maybe could land in 10.1

Moving to NW so the MR can be updated for 10.1

The approach on this issue seems to duplicate #3272587: Enable theme debugging by default in development.services.yml which was already closed as a duplicate of #2839709. Please read on:

Per @Cottser circa 2017 in #2839709-6: Make Debugging Twig easier:

there may have been a reason to not include it. Enabling twig debug can have side effects, because of the HTML comments added. For example, #2656728: Twig split in debug mode. Enabling auto_reload for development should be safe though.

On #2839709: Make Debugging Twig easier we took another approach, to add a separate twig-debug.services.yml because:

1. not all developers need twig debug enabled, only devs that need to find which template is rendering HTML, and override the template using one of the other suggestions.
2. enabling it by default can break developer's local environment in several ways (causing wasted time). See #2914733: [META] twig debug can break parts of site.
3. you cannot safely edit development.services.yml to disable twig debug, because it gets overwritten by composer scaffolding (if following best practices).

Have these questions been addressed? Can they? If not, I'm inclined to close this in favor of consolidating effort around #2839709: Make Debugging Twig easier and its waaaay more complicated successor #3278493: Make it easier for theme builders to enable Twig debugging and disable render cache.

The issue summary on this issue says:

Twig debugging is one of the most important features to enable when building a theme and it makes sense that it should be enabled by default in development.services.yml or at least the settings should be in the file but commented out with an explanation about what would happen if they are uncommented.

The approach on #2839709: Make Debugging Twig easier would have you literally uncomment a single line of code in settings.local.php to enable twig debugging, and doesnt suffer from any of the 3 drawbacks presented above. I would humbly ask for folks invested here to look there and see if there are any flaws in our thinking.

If you insist on continuing here, then at the very least I would have to insist on updating the code to add link to the Meta issue for known issues with enabling twig debug by default here: #2914733: [META] twig debug can break parts of site. Adding such a link is not going to help too much, because people will not know that Twig debugging is the root cause of many of these issues, adding to further confusion between differences on LOCAL / PROD.

Closing this as a duplicate of #2839709: Make Debugging Twig easier as well, thanks for outlining all the points @jwilson3 in comment #24 #3278887-24: Update development.services.yml to include twig debug by default

Cottser is of course right :D there are subtle side-effects of having this on that should be made clear. If you have very granular templates where it's rendered inside a tag, the HTML comments generated by twig_debug can break the layout, and some other subtle things around whitespace issues and HTML. Those are the side-effects we saw while adding twig to core.

Let's focus on the other issue and thanks for helping make the DX better!