Exit early with an error if assets config missing

.rubocop.yml

@@ -13,6 +13,8 @@ Lint/DuplicateBranch:
 Lint/EmptyFile:
   Exclude:
     - 'spec/fixtures/**/*.rb'
+Lint/NonLocalExitFromIterator:
+  Enabled: false
 Naming/HeredocDelimiterNaming:
   Enabled: false
 Naming/MethodParameterName:

lib/hanami/cli/commands/app/assets/command.rb

@@ -28,6 +28,13 @@ def call(**)
                 return
               end
 
+              slices.each do |slice|
+                unless assets_config(slice)
+                  out.puts "No assets config found for #{slice}. Please create a config/assets.js."
+                  return
+                end
+              end
+
               pids = slices_with_assets.map { |slice| fork_child_assets_command(slice) }
 
               Signal.trap("INT") do
@@ -88,17 +95,19 @@ def slice_assets?(slice)
               slice.root.join("assets").directory?
             end
 
+            # Returns the path to the assets config (`config/assets.js`) for the given slice.
+            #
+            # Prefers a config file local to the slice, otherwise falls back to app-level config.
+            # Returns nil if no config can be found.
+            #
             # @since 2.1.0
             # @api private
             def assets_config(slice)
               config = slice.root.join("config", "assets.js")
               return config if config.exist?
 
               config = slice.app.root.join("config", "assets.js")
-              return config if config.exist?
-
-              # TODO: real error
-              raise "no asset config found"
+              config if config.exist?
             end
 
             # @since 2.1.0

spec/unit/hanami/cli/commands/app/assets/compile_spec.rb

@@ -174,4 +174,19 @@ def before_prepare
       compile_command.call
     end
   end
+
+  describe "missing config/asset.js" do
+    def before_prepare
+      write "assets/.keep", ""
+      FileUtils.rm_f "config/assets.js"
+    end
+
+    it "prints an error message" do
+      expect(interactive_system_call).not_to receive(:call)
+
+      compile_command.call
+
+      expect(output).to eq "No assets config found for TestApp::App. Please create a config/assets.js.\n"
+    end
+  end
 end