Updated: Comment #12
Our route machine names in routing.yml files are not standardized. Some are module_name_sub_name, some are module_name.sub_name, and some may even be following other conventions. It's kind of a mess.
Core should standardize on one format, even though it is not technically required by Symfony.
The proposed standard is
where sub_name uses lower-case and underscores only. This appears to be what Symfony CMF does for cases where there is a concept of "module" (Symfony documentation itself does not appear to have a convention like this, as it has no moudles). See comment #6.
1. Agree upon the convention.
2. Document the convention as a coding standard.
3. Patch core to agree with this convention.
User interface changes
Route machine names would change, so if anyone already has alter hooks or any code that depends on specific machine names, that code would break.
(A list of related issues.)
Original report by webchick
If you grep for 'route_name' in 8.x right now, you see a lot of ones that look like this:
./core/modules/language/language.module: 'route_name' => 'language_negotiation_url',
and a few ones that look like this:
./core/modules/views_ui/views_ui.module: 'route_name' => 'views_ui.list',
The easiest thing to do is convert the views ones to under_scores, but I actually prefer the dot-convention myself, because it makes it clear that these are not callback functions, which they kind of look like.
FAILED: [[SimpleTest]]: [MySQL] Unable to apply patch route-names-1981368-28.patch. Unable to apply patch. See the log in the details link for more information.
PASSED: [[SimpleTest]]: [MySQL] 58,744 pass(es).
FAILED: [[SimpleTest]]: [MySQL] Setup environment: Test cancelled by admin prior to completion.