Use .html.twig instead of .twig file extension

You can roll the patch with git diff -C -M which reduces the patch size and makes it easier to review.

Fixed one of the tests, but the test that's failing in Drupal\system\Tests\Theme\ThemeTestTwig->testTemplateOverride() is failing in the sandbox as well.

Patch re-rolled with git diff -C -M as suggested in #3.

Can you explain why we're doing this? I'm looking at the official documentation at http://twig.sensiolabs.org/pdf/Twig.pdf and all I see are references to foo.twig, not foo.html.twig. Why are we inventing a Drupalism here?

@webchick - I just updated the issue summary to include a reference to #1804698: Consider using *.html.twig filename convention

Ok, awesome. Thanks for the reference! :)

Okay, managed to track this down. The failing test is only passing on HEAD because the template file is named .twig, not .html.twig. To really fix this, a hardcoded ".tpl" needs to be removed, and a couple strpos() need to be changed to strrpos().

#1678808-1: Defining a new theme engine with templates without .tpl.[template extension] breaks template suggestions (committed as part of #1696786: Integrate Twig into core: Implementation issue) removed one instance of hardcoded .tpl, and in the sandbox @Fabianx removed the other hardcoded .tpl instance with the same technique.

- if (($pos = strpos($template, '.tpl')) !== FALSE) {
+ if (($pos = strpos($template, '.')) !== FALSE) {

Previously strpos was searching for .tpl so it had a definite boundary and worked fine. Now that it's just searching for "." it should use strrpos instead to allow for template files with extra periods in them - like theme_test.template_test.tpl.php or theme_test.template_test.html.twig.

I'm not sure if we should add a test somewhere to make sure periods can be used in template suggestions. See also #1886448: Rewrite the theme registry into a proper service

@Fabianx should be credited as well on this commit since it incorporates his commit from the sandbox.

If you apply only the interdiff from #11 (without any .twig -> .html.twig changes) then the test will fail because the template file doesn't have an "extra" extension as in .tpl.php and .html.twig, so something like theme_test.template_test.haml would fail because the last part gets stripped away mistakenly. Here's a slightly better idea that just replaces the whole extension in the filename based on the $extension passed into drupal_find_theme_templates(), no strpos() of any sort needed.

Interdiff is from #5.

Happy to move this change into a separate issue if that makes more sense.

Failure in Drupal\openid\Tests\Upgrade\OpenIDAuthmapUpgradePathTest - looks like #1893800: Something is very, very wrong with update.php / upgrade tests... demons suspected, sending for a re-test.

#13: 1900458-13.patch queued for re-testing.

This is apparently blocking Twig conversion, so bumping priority.

Looks good, and the diffstat is nice since we're removing special casing.

Committed and pushed to 8.x. Thanks!

woot :)