Remove broken "default" storage initialiser

This initialiser was trying to setup the "default" storage if it didn't
exist in the config file but since the settingslogic tries to validate
that back to gitlab.yml it finds the setting doesn't exist and blows up.

Since this code doesn't actually work and since this is one part of the
reason why users cannot run gitlab without a "default" storage we should
remove it.

Changelog: fixed

config/initializers/1_settings.rb

@@ -760,13 +760,6 @@ Settings.gitlab_kas['internal_url'] ||= 'grpc://localhost:8153'
 #
 Settings['repositories'] ||= Settingslogic.new({})
 Settings.repositories['storages'] ||= {}
-unless Settings.repositories.storages['default']
-  Settings.repositories.storages['default'] ||= {}
-  # We set the path only if the default storage doesn't exist, in case it exists
-  # but follows the pre-9.0 configuration structure. `6_validations.rb` initializer
-  # will validate all storages and throw a relevant error to the user if necessary.
-  Settings.repositories.storages['default']['path'] ||= Settings.gitlab['user_home'] + '/repositories/'
-end
 
 Settings.repositories.storages.each do |key, storage|
   Settings.repositories.storages[key] = Gitlab::GitalyClient::StorageSettings.new(storage)

doc/administration/repository_storage_paths.md

@@ -120,17 +120,23 @@ For compatibility reasons `gitlab.yml` has a different structure than Omnibus Gi
 
 1. [Restart GitLab](restart_gitlab.md#installations-from-source) for the changes to take effect.
 
+1. [Configure where new repositories are stored](#configure-where-new-repositories-are-stored).
+
 **For Omnibus installations**
 
-Edit `/etc/gitlab/gitlab.rb` by appending the rest of the paths to the default one:
+1. Edit `/etc/gitlab/gitlab.rb` by appending the rest of the paths to the default one:
+
+   ```ruby
+   git_data_dirs({
+    "default" => { "path" => "/var/opt/gitlab/git-data" },
+    "storage1" => { "path" => "/mnt/storage1/git-data" },
+    "storage2" => { "path" => "/mnt/storage2/git-data" }
+   })
+   ```
+
+1. [Restart GitLab](restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
 
-```ruby
-git_data_dirs({
- "default" => { "path" => "/var/opt/gitlab/git-data" },
- "storage1" => { "path" => "/mnt/storage1/git-data" },
- "storage2" => { "path" => "/mnt/storage2/git-data" }
-})
-```
+1. [Configure where new repositories are stored](#configure-where-new-repositories-are-stored).
 
 NOTE:
 Omnibus stores the repositories in a `repositories` subdirectory of the `git-data` directory.
@@ -153,6 +159,17 @@ The higher the weight of a given repository storage path relative to other repos
 paths, the more often it is chosen. That is,
 `(storage weight) / (sum of all weights) * 100 = chance %`.
 
+By default, if repository weights have not been configured earlier:
+
+- `default` is weighted `100`.
+- All other storages are weighted `0`.
+
+NOTE:
+If all storage weights are `0` (for example, when `default` does not exist), GitLab attempts to
+create new repositories on `default`, regardless of the configuration or if `default` exists.
+See [the tracking issue](https://gitlab.com/gitlab-org/gitlab/-/issues/36175) for more information.
+information.
+
 ## Move repositories
 
 To move a repository to a different repository storage (for example, from `default` to `storage2`), use the