Add void return type to all preprocess hook implementations

Seems straight forward and a great start!

Applied the diff and there some instances not changed.

$ grep --exclude-dir={assets,node_modules,vendor.phpstan=tmp} --exclude=\*.cspellcache --exclude=\*.yarn -r '^function.*_preprocess_' core | grep -v void
core/lib/Drupal/Core/Render/theme.api.php:function hook_preprocess_HOOK(&$variables) {
core/lib/Drupal/Core/Render/theme.api.php:function hook_template_preprocess_default_variables_alter(&$variables) {
core/themes/claro/claro.theme:function _claro_preprocess_file_and_image_widget(array &$variables) {
core/includes/theme.inc:function _template_preprocess_default_variables() {
core/modules/system/tests/themes/test_theme/test_theme.theme:function test_theme_preprocess_theme_test_preprocess_suggestions__suggestion(&$variables) {
core/modules/system/tests/themes/test_theme/test_theme.theme:function test_theme_preprocess_theme_test_preprocess_suggestions__kitten(&$variables) {
core/modules/system/tests/themes/test_theme/test_theme.theme:function test_theme_preprocess_theme_test_preprocess_suggestions__kitten__flamingo(&$variables) {
core/modules/system/tests/themes/test_theme/test_theme.theme:function test_theme_preprocess_theme_test_preprocess_suggestions__kitten__meerkat__tarsier__moose(&$variables) {
core/modules/system/tests/modules/theme_test/theme_test.module:function theme_test_theme_suggestions_theme_test_preprocess_suggestions($variables) {

Should they be done here or somewhere else?

• hook_preprocess_HOOK should be updated here
• hook_template_preprocess_default_variables_alter is a separate hook. I think once we get through the most common hooks we could batch a bunch of less common hooks together.
• _claro_preprocess_file_and_image_widget is not a hook implementation
• _template_preprocess_default_variables is not a hook implementation
• test_theme_preprocess_theme_test_preprocess_suggestions__* look like they should be updated here
• theme_test_theme_suggestions_theme_test_preprocess_suggestions implements theme_test_theme_suggestions_theme_test_preprocess_suggestions and furthermore it returns an array

Thanks for the thorough checking @quietone and the detailed instructions @mstrelan. I fixed the ones you mentioned, hope I didn't miss anything.

Thanks @tstoeckler, this looks good to me. Will leave for someone else to RTBC since I did the original MR.

This looks great but had it been rebase since the hook conversion? The return hints will still apply but baseline will need regenerating.

If it was rebased then I can rtbc.

@nicxvan yes, was rebased first, and I checked it merges cleanly to 11.x

Great!

Committed/pushed to 11.x and cherry-picked to 11.1.x thanks!

quietone → closed merge request !9941

Automatically closed - issue fixed for 2 weeks with no activity.