Only allow route names, deprecate support for route objects in UrlGenerator methods

+++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
@@ -430,7 +438,11 @@ protected function getRoute($name) {
+   * @deprecated in drupal:9.1.0 and is removed in drupal:10.0.0

@@ -438,7 +450,11 @@ public function supports($name) {
+   * @deprecated in drupal:9.1.0 and is removed in drupal:10.0.0.

it needs @see to CR and explanation with replacement, or may use follow-up

1. +++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
   @@ -417,6 +423,8 @@ protected function processRoute($name, SymfonyRoute $route, array &$parameters,
   +   * @internal
   +   *
       * @see \Drupal\Core\Routing\RouteProviderInterface
   ...
      protected function getRoute($name) {
   

   This method overriden only once in \Drupal\Core\Routing\NullGenerator::getRoute() and implementation sounds for legacy support, could use follow-up to clean-up for d10

2. +++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
   @@ -430,7 +438,7 @@ protected function getRoute($name) {
   -   * {@inheritdoc}
   +   * Checks if route name is a string or route object.
   
   @@ -438,7 +446,7 @@ public function supports($name) {
   -   * {@inheritdoc}
   +   * Gets either the route name or a string based on the route object.
   

   not sure this change needed, as there's 2 more classes now implements this methods and have broken "inheritdoc" there too, see #3151017-10: Deprecate UrlGenerator::supports() and UrlGenerator::getRouteDebugMessage()

   - \Drupal\Core\Render\MetadataBubblingUrlGenerator::supports
   - \Drupal\help_test\SupernovaGenerator::supports

+++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
@@ -127,6 +127,9 @@ public function isStrictRequirements() {
   public function getPathFromRoute($name, $parameters = []) {
+    if (!is_string($name)) {
+      @trigger_error('Passing a route object to ' . __METHOD__ . ' is deprecated in drupal:9.1.0 and will not be supported in drupal:10.0.0. Pass the route name instead. See https://www.drupal.org/node/3172280', E_USER_DEPRECATED);
+    }

+100 for this per #2491981: There are too many ways to generate URLs and links!

Can we still land this? 🤞🤓

reroll for 9.2

The Needs Review Queue Bot tested this issue. It either no longer applies to Drupal core, or fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

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re-roll for 10.1 and there's only context conflict with #3151017: Deprecate UrlGenerator::supports() and UrlGenerator::getRouteDebugMessage() so better to commit it

+++ b/core/modules/comment/src/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
@@ -178,7 +178,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
-            $build['pager']['#route_name'] = $this->routeMatch->getRouteObject();
+            $build['pager']['#route_name'] = $this->routeMatch->getRouteName();

+++ b/core/modules/config_translation/src/Form/ConfigTranslationFormBase.php
@@ -219,7 +219,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
-      $this->mapper->getOverviewRoute(),
+      $this->mapper->getOverviewRouteName(),

this 2 places anyway needs fix

It needs follow-up to remove deprecated methods in D11 and new method UrlGenerator::getRouteStringIdentifier() added in related issue #3151017: Deprecate UrlGenerator::supports() and UrlGenerator::getRouteDebugMessage()

Filed follow-up #3339710: Disallow passing route objects to UrlGenerator methods and waiting for #3151017: Deprecate UrlGenerator::supports() and UrlGenerator::getRouteDebugMessage()

blocker commited, here's re-roll and polishing of test and place to throw deprecation

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

Consult the Drupal Contributor Guide to find step-by-step guides for working with issues.

Umm, issue with the bot

Somehow re-testing aborted, queued PHP 8.2 meantime but curious if there's some performance regression happened

tests are passed, I see no difference in time - the same 1h for run

Deprecation message is up to date,
Change record is simple and clear.
Has test coverage for deprecation.
Code looks good to me.

Committed to 10.1.x, thanks!