Skip generate_packs when shakapacker precompile hook configured

This change prevents react_on_rails from running generate_packs twice
when shakapacker has a precompile hook configured that already runs it.

Changes:
- Add PackerUtils.shakapacker_precompile_hook_configured? to detect hook
- Skip generate_packs in assets:precompile if hook is configured
- Skip generate_packs in bin/dev if hook is configured
- Add comprehensive test coverage for new behavior

This ensures generate_packs runs only once during both:
- Production asset precompilation (assets:precompile)
- Development server startup (bin/dev)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

lib/react_on_rails/configuration.rb

@@ -238,7 +238,11 @@ def adjust_precompile_task
       raise(ReactOnRails::Error, compile_command_conflict_message) if ReactOnRails::PackerUtils.precompile?
 
       precompile_tasks = lambda {
-        Rake::Task["react_on_rails:generate_packs"].invoke
+        # Skip generate_packs if shakapacker has a precompile hook configured
+        unless ReactOnRails::PackerUtils.shakapacker_precompile_hook_configured?
+          Rake::Task["react_on_rails:generate_packs"].invoke
+        end
+
         Rake::Task["react_on_rails:assets:webpack"].invoke
 
         # VERSIONS is per the shakacode/shakapacker clean method definition.

lib/react_on_rails/dev/pack_generator.rb

@@ -8,6 +8,12 @@ module Dev
     class PackGenerator
       class << self
         def generate(verbose: false)
+          # Skip if shakapacker has a precompile hook configured
+          if ReactOnRails::PackerUtils.shakapacker_precompile_hook_configured?
+            puts "⏭️  Skipping pack generation (handled by shakapacker precompile hook)" if verbose
+            return
+          end
+
           if verbose
             puts "📦 Generating React on Rails packs..."
             success = run_pack_generation

lib/react_on_rails/packer_utils.rb

@@ -166,5 +166,21 @@ def self.raise_shakapacker_version_incompatible_for_basic_pack_generation
 
       raise ReactOnRails::Error, msg
     end
+
+    # Check if shakapacker.yml has a precompile hook configured
+    # This prevents react_on_rails from running generate_packs twice
+    def self.shakapacker_precompile_hook_configured?
+      return false unless defined?(::Shakapacker)
+
+      config_data = ::Shakapacker.config.send(:data)
+      hooks = config_data.dig("hooks", "precompile")
+
+      return false unless hooks
+
+      # Check if any hook contains the generate_packs rake task
+      Array(hooks).any? { |hook| hook.to_s.include?("react_on_rails:generate_packs") }
+    rescue StandardError
+      false
+    end
   end
 end

spec/react_on_rails/dev/pack_generator_spec.rb

@@ -5,166 +5,190 @@
 
 RSpec.describe ReactOnRails::Dev::PackGenerator do
   describe ".generate" do
-    context "when in Bundler context with Rails available" do
-      let(:mock_task) { instance_double(Rake::Task) }
-      let(:mock_rails_app) do
-        # rubocop:disable RSpec/VerifiedDoubles
-        double("Rails.application").tap do |app|
-          allow(app).to receive(:load_tasks)
-          allow(app).to receive(:respond_to?).with(:load_tasks).and_return(true)
-        end
-        # rubocop:enable RSpec/VerifiedDoubles
-      end
+    before do
+      # Mock the precompile hook check to return false by default
+      allow(ReactOnRails::PackerUtils).to receive(:shakapacker_precompile_hook_configured?).and_return(false)
+    end
 
+    context "when shakapacker precompile hook is configured" do
       before do
-        # Setup Bundler context
-        stub_const("Bundler", Module.new)
-        allow(ENV).to receive(:[]).and_call_original
-        allow(ENV).to receive(:[]).with("BUNDLE_GEMFILE").and_return("/path/to/Gemfile")
-
-        # Setup Rails availability
-        app = mock_rails_app
-        rails_module = Module.new do
-          define_singleton_method(:application) { app }
-          define_singleton_method(:respond_to?) { |method, *| method == :application }
-        end
-        stub_const("Rails", rails_module)
-
-        # Mock Rake::Task at the boundary
-        allow(Rake::Task).to receive(:task_defined?).with("react_on_rails:generate_packs").and_return(false)
-        allow(Rake::Task).to receive(:[]).with("react_on_rails:generate_packs").and_return(mock_task)
-        allow(mock_task).to receive(:reenable)
-        allow(mock_task).to receive(:invoke)
+        allow(ReactOnRails::PackerUtils).to receive(:shakapacker_precompile_hook_configured?).and_return(true)
       end
 
-      it "runs pack generation successfully in verbose mode using direct rake execution" do
+      it "skips pack generation in verbose mode" do
         expect { described_class.generate(verbose: true) }
-          .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
-
-        expect(mock_task).to have_received(:invoke)
-        expect(mock_rails_app).to have_received(:load_tasks)
+          .to output(/⏭️  Skipping pack generation \(handled by shakapacker precompile hook\)/)
+          .to_stdout_from_any_process
       end
 
-      it "runs pack generation successfully in quiet mode using direct rake execution" do
+      it "skips pack generation in quiet mode" do
         expect { described_class.generate(verbose: false) }
-          .to output(/📦 Generating packs\.\.\. ✅/).to_stdout_from_any_process
-
-        expect(mock_task).to have_received(:invoke)
+          .not_to output.to_stdout_from_any_process
       end
+    end
 
-      it "exits with error when pack generation fails" do
-        allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Task failed"))
+    context "when shakapacker precompile hook is not configured" do
+      context "when in Bundler context with Rails available" do
+        let(:mock_task) { instance_double(Rake::Task) }
+        let(:mock_rails_app) do
+          # rubocop:disable RSpec/VerifiedDoubles
+          double("Rails.application").tap do |app|
+            allow(app).to receive(:load_tasks)
+            allow(app).to receive(:respond_to?).with(:load_tasks).and_return(true)
+          end
+          # rubocop:enable RSpec/VerifiedDoubles
+        end
 
-        # Mock STDERR.puts to capture output
-        error_output = []
-        # rubocop:disable Style/GlobalStdStream
-        allow(STDERR).to receive(:puts) { |msg| error_output << msg }
-        # rubocop:enable Style/GlobalStdStream
+        before do
+          # Setup Bundler context
+          stub_const("Bundler", Module.new)
+          allow(ENV).to receive(:[]).and_call_original
+          allow(ENV).to receive(:[]).with("BUNDLE_GEMFILE").and_return("/path/to/Gemfile")
+
+          # Setup Rails availability
+          app = mock_rails_app
+          rails_module = Module.new do
+            define_singleton_method(:application) { app }
+            define_singleton_method(:respond_to?) { |method, *| method == :application }
+          end
+          stub_const("Rails", rails_module)
+
+          # Mock Rake::Task at the boundary
+          allow(Rake::Task).to receive(:task_defined?).with("react_on_rails:generate_packs").and_return(false)
+          allow(Rake::Task).to receive(:[]).with("react_on_rails:generate_packs").and_return(mock_task)
+          allow(mock_task).to receive(:reenable)
+          allow(mock_task).to receive(:invoke)
+        end
 
-        expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
-        expect(error_output.join("\n")).to match(/Error generating packs: Task failed/)
-      end
+        it "runs pack generation successfully in verbose mode using direct rake execution" do
+          expect { described_class.generate(verbose: true) }
+            .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
 
-      it "outputs errors to stderr even in silent mode" do
-        allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Silent mode error"))
+          expect(mock_task).to have_received(:invoke)
+          expect(mock_rails_app).to have_received(:load_tasks)
+        end
 
-        # Mock STDERR.puts to capture output
-        error_output = []
-        # rubocop:disable Style/GlobalStdStream
-        allow(STDERR).to receive(:puts) { |msg| error_output << msg }
-        # rubocop:enable Style/GlobalStdStream
+        it "runs pack generation successfully in quiet mode using direct rake execution" do
+          expect { described_class.generate(verbose: false) }
+            .to output(/📦 Generating packs\.\.\. ✅/).to_stdout_from_any_process
 
-        expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
-        expect(error_output.join("\n")).to match(/Error generating packs: Silent mode error/)
-      end
+          expect(mock_task).to have_received(:invoke)
+        end
 
-      it "includes backtrace in error output when DEBUG env is set" do
-        allow(ENV).to receive(:[]).with("DEBUG").and_return("true")
-        allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Debug error"))
+        it "exits with error when pack generation fails" do
+          allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Task failed"))
 
-        # Mock STDERR.puts to capture output
-        error_output = []
-        # rubocop:disable Style/GlobalStdStream
-        allow(STDERR).to receive(:puts) { |msg| error_output << msg }
-        # rubocop:enable Style/GlobalStdStream
+          # Mock STDERR.puts to capture output
+          error_output = []
+          # rubocop:disable Style/GlobalStdStream
+          allow(STDERR).to receive(:puts) { |msg| error_output << msg }
+          # rubocop:enable Style/GlobalStdStream
 
-        expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
-        expect(error_output.join("\n")).to match(/Error generating packs: Debug error.*pack_generator_spec\.rb/m)
-      end
+          expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
+          expect(error_output.join("\n")).to match(/Error generating packs: Task failed/)
+        end
 
-      it "suppresses stdout in silent mode" do
-        # Mock task to produce output
-        allow(mock_task).to receive(:invoke) do
-          puts "This should be suppressed"
+        it "outputs errors to stderr even in silent mode" do
+          allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Silent mode error"))
+
+          # Mock STDERR.puts to capture output
+          error_output = []
+          # rubocop:disable Style/GlobalStdStream
+          allow(STDERR).to receive(:puts) { |msg| error_output << msg }
+          # rubocop:enable Style/GlobalStdStream
+
+          expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
+          expect(error_output.join("\n")).to match(/Error generating packs: Silent mode error/)
         end
 
-        expect { described_class.generate(verbose: false) }
-          .not_to output(/This should be suppressed/).to_stdout_from_any_process
-      end
-    end
+        it "includes backtrace in error output when DEBUG env is set" do
+          allow(ENV).to receive(:[]).with("DEBUG").and_return("true")
+          allow(mock_task).to receive(:invoke).and_raise(StandardError.new("Debug error"))
 
-    context "when not in Bundler context" do
-      before do
-        # Ensure we're not in Bundler context
-        hide_const("Bundler") if defined?(Bundler)
-      end
+          # Mock STDERR.puts to capture output
+          error_output = []
+          # rubocop:disable Style/GlobalStdStream
+          allow(STDERR).to receive(:puts) { |msg| error_output << msg }
+          # rubocop:enable Style/GlobalStdStream
 
-      it "runs pack generation successfully in verbose mode using bundle exec" do
-        allow(described_class).to receive(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
-          .and_return(true)
+          expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
+          expect(error_output.join("\n")).to match(/Error generating packs: Debug error.*pack_generator_spec\.rb/m)
+        end
 
-        expect { described_class.generate(verbose: true) }
-          .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
+        it "suppresses stdout in silent mode" do
+          # Mock task to produce output
+          allow(mock_task).to receive(:invoke) do
+            puts "This should be suppressed"
+          end
 
-        expect(described_class).to have_received(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+          expect { described_class.generate(verbose: false) }
+            .not_to output(/This should be suppressed/).to_stdout_from_any_process
+        end
       end
 
-      it "runs pack generation successfully in quiet mode using bundle exec" do
-        allow(described_class).to receive(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
-                out: File::NULL, err: File::NULL)
-          .and_return(true)
+      context "when not in Bundler context" do
+        before do
+          # Ensure we're not in Bundler context
+          hide_const("Bundler") if defined?(Bundler)
+        end
 
-        expect { described_class.generate(verbose: false) }
-          .to output(/📦 Generating packs\.\.\. ✅/).to_stdout_from_any_process
+        it "runs pack generation successfully in verbose mode using bundle exec" do
+          allow(described_class).to receive(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+            .and_return(true)
 
-        expect(described_class).to have_received(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
-                out: File::NULL, err: File::NULL)
-      end
+          expect { described_class.generate(verbose: true) }
+            .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
 
-      it "exits with error when pack generation fails" do
-        allow(described_class).to receive(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
-                out: File::NULL, err: File::NULL)
-          .and_return(false)
+          expect(described_class).to have_received(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+        end
 
-        expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
-      end
-    end
+        it "runs pack generation successfully in quiet mode using bundle exec" do
+          allow(described_class).to receive(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
+                  out: File::NULL, err: File::NULL)
+            .and_return(true)
 
-    context "when Rails is not available" do
-      before do
-        stub_const("Bundler", Module.new)
-        allow(ENV).to receive(:[]).and_call_original
-        allow(ENV).to receive(:[]).with("BUNDLE_GEMFILE").and_return("/path/to/Gemfile")
+          expect { described_class.generate(verbose: false) }
+            .to output(/📦 Generating packs\.\.\. ✅/).to_stdout_from_any_process
+
+          expect(described_class).to have_received(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
+                  out: File::NULL, err: File::NULL)
+        end
 
-        # Rails not available
-        hide_const("Rails") if defined?(Rails)
+        it "exits with error when pack generation fails" do
+          allow(described_class).to receive(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs",
+                  out: File::NULL, err: File::NULL)
+            .and_return(false)
+
+          expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
+        end
       end
 
-      it "falls back to bundle exec when Rails is not defined" do
-        allow(described_class).to receive(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
-          .and_return(true)
+      context "when Rails is not available" do
+        before do
+          stub_const("Bundler", Module.new)
+          allow(ENV).to receive(:[]).and_call_original
+          allow(ENV).to receive(:[]).with("BUNDLE_GEMFILE").and_return("/path/to/Gemfile")
 
-        expect { described_class.generate(verbose: true) }
-          .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
+          # Rails not available
+          hide_const("Rails") if defined?(Rails)
+        end
+
+        it "falls back to bundle exec when Rails is not defined" do
+          allow(described_class).to receive(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+            .and_return(true)
 
-        expect(described_class).to have_received(:system)
-          .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+          expect { described_class.generate(verbose: true) }
+            .to output(/📦 Generating React on Rails packs.../).to_stdout_from_any_process
+
+          expect(described_class).to have_received(:system)
+            .with("bundle", "exec", "rake", "react_on_rails:generate_packs")
+        end
       end
     end
   end