Fix URL blocker when object storage enabled but type is disabled

This commit fixes two problems:

1. If the object type is disabled but object storage is enabled (as it
is in Cloud Native GitLab), previously the URL blocker would attempt
to drill into the endpoint. We now check that the type is also enabled.

2. Due to a Settingslogic bug
(https://gitlab.com/gitlab-org/gitlab/-/issues/286873), the use of
`default` anywhere causes `Hash#default` to be overriden for the
`Settingslogic` class. If `connection` field `connection.endpoint` is
omittted from object storage config, this previously would result in
an error:

```
ArgumentError: wrong number of arguments (given 1, expected 0)>
```

We need to call `to_h` because we define `default` as a Gitaly storage
name in GitLab Charts.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/357340

Changelog: fixed

lib/gitlab/url_blocker.rb

@@ -289,9 +289,10 @@ module Gitlab
         ObjectStoreSettings::SUPPORTED_TYPES.collect do |type|
           section_setting = config.try(type)
 
-          next unless section_setting
+          next unless section_setting && section_setting['enabled']
 
-          object_store_setting = section_setting['object_store']
+          # Use #to_h to avoid Settingslogic bug: https://gitlab.com/gitlab-org/gitlab/-/issues/286873
+          object_store_setting = section_setting['object_store']&.to_h
 
           next unless object_store_setting && object_store_setting['enabled']
 

spec/lib/gitlab/import_export/command_line_util_spec.rb

@@ -167,6 +167,7 @@ RSpec.describe Gitlab::ImportExport::CommandLineUtil do
       context 'for object_storage uri' do
         let(:enabled_object_storage_setting) do
           {
+            'enabled' => true,
             'object_store' =>
             {
               'enabled' => true,

spec/lib/gitlab/url_blocker_spec.rb

@@ -43,6 +43,7 @@ RSpec.describe Gitlab::UrlBlocker, :stub_invalid_dns_only do
       let(:import_url) { "#{host}/external-diffs/merge_request_diffs/mr-1/diff-1" }
       let(:enabled_object_storage_setting) do
         {
+          'enabled' => true,
           'object_store' =>
           {
             'enabled' => true,
@@ -81,6 +82,49 @@ RSpec.describe Gitlab::UrlBlocker, :stub_invalid_dns_only do
             let(:expected_hostname) { nil }
           end
         end
+
+        context 'when LFS object storage is enabled' do
+          let(:lfs_config) do
+            {
+              'enabled' => lfs_enabled,
+              # This nesting of Settingslogic is necessary to trigger the bug
+              'object_store' => Settingslogic.new({ 'enabled' => true })
+            }
+          end
+
+          let(:config) do
+            {
+              'gitlab' => Gitlab.config.gitlab,
+              'repositories' => { 'storages' => { 'default' => 'test' } },
+              'lfs' => Settingslogic.new(lfs_config)
+            }
+          end
+
+          let(:host) { 'http://127.0.0.1:9000' }
+          let(:settings) { Settingslogic.new(config) }
+
+          before do
+            allow(Gitlab).to receive(:config).and_return(settings)
+            # Triggers Settingslogic bug: https://gitlab.com/gitlab-org/gitlab/-/issues/286873
+            settings.repositories.storages.default
+          end
+
+          context 'when LFS is disabled' do
+            let(:lfs_enabled) { false }
+
+            it 'raises an error' do
+              expect { subject }.to raise_error(described_class::BlockedUrlError)
+            end
+          end
+
+          context 'when LFS is enabled with no connection endpoint' do
+            let(:lfs_enabled) { true }
+
+            it 'raises an error' do
+              expect { subject }.to raise_error(described_class::BlockedUrlError)
+            end
+          end
+        end
       end
 
       context 'when allow_object_storage is false' do