Smart proxy sync can fail when host has no bound container repos

lib/smart_proxy_container_gateway/container_gateway_main.rb

@@ -195,29 +195,40 @@ def update_host_repo_mapping(host_repo_maps)
         # Insert all in a single transaction
         database.connection.transaction(isolation: :serializable, retry_on: [Sequel::SerializationFailure]) do
           hosts_repositories.delete
-          hosts_repositories.import(%i[repository_id host_id], entries)
+          hosts_repositories.import(%i[repository_id host_id], entries) unless entries.nil? || entries.empty?
         end
       end
 
       def build_host_repository_mapping(host_repo_maps)
+        return [] if host_repo_maps['hosts'].nil?
+
         hosts = database.connection[:hosts]
         repositories = database.connection[:repositories]
+
         entries = host_repo_maps['hosts'].flat_map do |host_map|
           host_map.filter_map do |host_uuid, repos|
-            host = hosts[{ uuid: host_uuid }]
-            next unless host
-
-            repo_names = repos
-                         .select { |repo| repo['auth_required'].to_s.downcase == "true" }
-                         .map { |repo| repo['repository'] }
-
-            repositories
-              .where(name: repo_names, auth_required: true)
-              .select(:id)
-              .map { |repo| [repo[:id], host[:id]] }
+            build_host_entries(hosts, repositories, host_uuid, repos)
           end
         end
-        entries.flatten!(1)
+        entries&.flatten(1)&.compact
+      end
+
+      def build_host_entries(hosts, repositories, host_uuid, repos)
+        host = hosts[{ uuid: host_uuid }]
+        return unless host
+        return if repos.nil? || repos.empty?
+
+        repo_names = extract_auth_required_repo_names(repos)
+        repositories
+          .where(name: repo_names, auth_required: true)
+          .select(:id)
+          .map { |repo| [repo[:id], host[:id]] }
+      end
+
+      def extract_auth_required_repo_names(repos)
+        repos
+          .select { |repo| repo['auth_required'].to_s.downcase == "true" }
+          .map { |repo| repo['repository'] }
       end
 
       def update_host_repositories(uuid, repositories)

test/container_gateway_backend_test.rb

@@ -233,5 +233,99 @@ def clears_existing_host_repo_mapping_before_update
     assert_equal [[updated_repo[:id], host[:id]]],
                  @database.connection[:hosts_repositories].select_map(%i[repository_id host_id])
   end
+
+  def test_build_host_repository_mapping_with_nil_hosts
+    host_repo_maps = { 'hosts' => nil }
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+    assert_empty result
+  end
+
+  def test_build_host_repository_mapping_with_empty_hosts
+    host_repo_maps = { 'hosts' => [] }
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+    assert_empty result
+  end
+
+  def test_build_host_repository_mapping_with_nonexistent_host
+    @container_gateway_main.update_repository_list([{ 'repository' => 'test_repo1', 'auth_required' => true }])
+
+    host_repo_maps = {
+      'hosts' => [
+        { 'nonexistent-uuid' => [{ 'repository' => 'test_repo1', 'auth_required' => true }] }
+      ]
+    }
+
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+    assert_empty result
+  end
+
+  def test_build_host_repository_mapping_with_nil_repos
+    @database.connection[:hosts].insert(uuid: 'host-uuid-1')
+
+    host_repo_maps = {
+      'hosts' => [
+        { 'host-uuid-1' => nil }
+      ]
+    }
+
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+    assert_empty result
+  end
+
+  def test_build_host_repository_mapping_with_empty_repos
+    @database.connection[:hosts].insert(uuid: 'host-uuid-1')
+
+    host_repo_maps = {
+      'hosts' => [
+        { 'host-uuid-1' => [] }
+      ]
+    }
+
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+    assert_empty result
+  end
+
+  def test_build_host_repository_mapping_filters_non_auth_required_repos
+    repo_list = [{ 'repository' => 'public_repo', 'auth_required' => false },
+                 { 'repository' => 'private_repo', 'auth_required' => true }]
+    @container_gateway_main.update_repository_list(repo_list)
+    @database.connection[:hosts].insert(uuid: 'host-uuid-1')
+
+    host_repo_maps = {
+      'hosts' => [
+        { 'host-uuid-1' => [
+          { 'repository' => 'public_repo', 'auth_required' => false },
+          { 'repository' => 'private_repo', 'auth_required' => true }
+        ] }
+      ]
+    }
+
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+
+    host = @database.connection[:hosts].first(uuid: 'host-uuid-1')
+    private_repo = @database.connection[:repositories].first(name: 'private_repo')
+
+    assert_equal [[private_repo[:id], host[:id]]], result
+  end
+
+  def test_build_host_repository_mapping_handles_mixed_scenarios
+    @container_gateway_main.update_repository_list([{ 'repository' => 'test_repo1', 'auth_required' => true }])
+    @database.connection[:hosts].insert(uuid: 'valid-host')
+
+    host_repo_maps = {
+      'hosts' => [
+        { 'valid-host' => [{ 'repository' => 'test_repo1', 'auth_required' => true }] },
+        { 'invalid-host' => [{ 'repository' => 'test_repo1', 'auth_required' => true }] },
+        { 'empty-repos-host' => [] }
+      ]
+    }
+
+    result = @container_gateway_main.build_host_repository_mapping(host_repo_maps)
+
+    host = @database.connection[:hosts].first(uuid: 'valid-host')
+    repo = @database.connection[:repositories].first(name: 'test_repo1')
+
+    assert_equal [[repo[:id], host[:id]]], result
+  end
 end
 # rubocop:enable Metrics/AbcSize