In the documentation, change all instances of "an URL" to "a URL".

Thanks for the issue and patch! I gather that this issue should be a child of #2574981: Fix grammar ("an URL" should be "a URL") and consistent use of URL (not "url" / "Url") in documentation only, part 1 so adding that.

Also we can update API docs in 8.0.x and 8.1.x, so changing this to an 8.0.x issue to indicate that.

The patch has some problems though, mostly due to one thing.

There is a class called "Url" that exists in Drupal Core. So even though when we're talking about a URL (in the sense of something like "https://www.drupal.org"), the correct capitalization of that is "URL", when we're talking about an object of this class, the correct phrase would be "a Url object". Or really, it should say:
a \Drupal\Core\Url object

So, I've noted where I think in the patch it's referring to the Url object and not a URL string. These all need to be updated, or at least the capitalization should not be changed to "URL" and we can make those changes to "a \Drupal\Core\Url object" in a separate issue if you prefer not to expand the scope here.

1. +++ b/core/lib/Drupal/Core/Path/PathValidatorInterface.php
   @@ -13,7 +13,7 @@
   +   * Returns a URL object, if the path is valid and accessible.
   

   This is the object. Incorrect caps.

2. +++ b/core/lib/Drupal/Core/Path/PathValidatorInterface.php
   @@ -24,7 +24,7 @@
   +   * Returns a URL object, if the path is valid.
   

   Object.

3. +++ b/core/lib/Drupal/Core/Template/TwigExtension.php
   @@ -254,7 +254,7 @@ public function getUrl($name, $parameters = array(), $options = array()) {
   -   * Gets a rendered link from an url object.
   +   * Gets a rendered link from a URL object.
   

   Object.

4. +++ b/core/modules/language/src/Form/NegotiationUrlForm.php
   @@ -100,7 +100,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
   -      '#description' => $this->t('The domain names to use for these languages. <strong>Modifying this value may break existing URLs. Use with caution in a production environment.</strong> Example: Specifying "de.example.com" as language domain for German will result in an URL like "http://de.example.com/contact".'),
   +      '#description' => $this->t('The domain names to use for these languages. <strong>Modifying this value may break existing URLs. Use with caution in a production environment.</strong> Example: Specifying "de.example.com" as language domain for German will result in a URL like "http://de.example.com/contact".'),
   

   This change does not belong in the patch, since it is UI text. This patch should only be for API documentation. We cannot change UI text for minor things like this in 8.0.x.

5. +++ b/core/modules/link/src/LinkItemInterface.php
   @@ -41,7 +41,7 @@ public function isExternal();
   -   *   Returns an Url object.
   +   *   Returns a URL object.
   

   Object.

6. +++ b/core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php
   @@ -240,7 +240,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
   -   *   An Url object.
   +   *   A URL object.
   

   Object.

7. +++ b/core/modules/rest/src/Tests/AuthTest.php
   @@ -74,7 +74,7 @@ public function testRead() {
   -   *   An Url object.
   +   *   A URL object.
   

   Object.

8. +++ b/core/modules/views/src/Plugin/views/display/DisplayRouterInterface.php
   @@ -39,7 +39,7 @@ public function collectRoutes(RouteCollection $collection);
   -   * Generates an URL to this display.
   +   * Generates a URL to this display.
       *
       * @return \Drupal\Core\Url
   

   Here it should probably say "a Url object" because that is what is being generated, not really a URL per se.

As another note, I think it would be best to do the issues that fix the capitalization first, then go back and fix the "an URL" problems later, but it's up to you. You can also just only do "a" to "an" in this patch if you do not take what was correct capitalization for the object and make it incorrect. That would actually be more in keeping with the stated scope of this issue.

@jhodgdon According to the stated scope of this issue, I have only changed "an" to "a" in this patch.
(Task 1 in https://www.drupal.org/node/2574981 - Comment #45)

All instances of "Url" or "url" have been restored to their original state.
The URL capitalization should be performed on another issue, no? All this would be correct?

I am looking into it.

There are still issues of "Url" to "URL" and "an URL" to "a URL" in following files.

1. https://www.drupal.org/files/issues/interdiff-2672442-6-10.txt
2. https://www.drupal.org/files/issues/in_the_documentation-2672442-10.patch
3. https://www.drupal.org/files/issues/interdiff-2672442-1-2.txt

@jeevanbhushetty See #11.
I think that the URL capitalization should be performed on another issue and in this one we should just change "an" to "a".

Yes, we are *only* chainging "an" to "a" when "url" (with any capitalization) follows it, and not doing anything about capitalization problems in this issue. And only in API docs, not UI text.

So the changes in the patch are fine. I also verified with grep that it fixes all instances in core of "an url" (any caps).

So thanks for the patch and for making a well-scoped issue! On to the next part in another issue? :)

Needs a re-roll for 8.1.x.

I have re rolled against 8.1.x

Thanks! The patch in #18 looks good, and is identical to the patch in #11. Except in #11, this capitalization change shouldn't be made:

+++ b/core/modules/rest/src/Tests/AuthTest.php
@@ -74,7 +74,7 @@ public function testRead() {
-   *   An Url object.
+   *   A URL object.

This should be "A Url object.". I missed that in my earlier review.

So... We can commit the patch in #18 to 8.1.x, and then we need to go back and make a new patch for 8.0.x. Accordingly, setting to RTBC for 8.1.x and tagging with "needs backport" for 8.0.x.

This it's the patch for 8.0.x
This solves a mistake indicated on #20.
Attach interdiff between #11 and #21.

Thanks! So the patch in #18 should be good for 8.1.x, and #21 for 8.0.x.

Committed/pushed to 8.1.x, thanks!

#21 doesn't apply. I'm going to go ahead and mark this fixed - can re-open if someone re-rolls.

Huh? #21 seems to apply to 8.0.x. I went ahead and committed it, after using git diff -- color-words to verify once again that all it does is change an to a before url.