Keep Rails assets stable across caches

CHANGELOG.md

@@ -1,10 +1,14 @@
 # Changelog
 
+## 0.1.0.alpha.3 - 2026-08-27
+
+- Remove Bundler cache metadata before compiling assets so cold and restored Rails builds stay identical.
+
 ## 0.1.0.alpha.2 - 2026-08-27
 
 - Stream clean, Docker-style build steps and command output through Dagger Ruby.
 - Run Bundler with the available CPUs unless `BUNDLE_JOBS` is explicitly configured.
-- Keep Rails artifacts identical across cold and restored dependency caches.
+- Keep dependency cache metadata out of Rails artifacts.
 
 ## 0.1.0.alpha.1 - 2026-08-27
 

lib/boringbuilder/ruby_build.rb

@@ -63,6 +63,12 @@ def container
         name: "[build] RUN bundle check",
         workdir: application_path
       )
+      builder = pipeline.exec(
+        builder,
+        %w[rm -rf .bundle/cache],
+        name: "[build] RUN rm -rf .bundle/cache",
+        workdir: application_path
+      )
       builder = precompile(builder)
       builder = pipeline.step("[build] Write Bundler configuration", builder) { write_bundle_config(_1) }
 

lib/boringbuilder/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module BoringBuilder
-  VERSION = "0.1.0.alpha.2"
+  VERSION = "0.1.0.alpha.3"
 end

test/boringbuilder/rails_build_test.rb

@@ -26,6 +26,19 @@ def test_builds_a_production_rails_container_with_oci_metadata
     assert_includes client.calls, [:with_user, ["rails"], {}]
   end
 
+  def test_removes_dependency_metadata_before_compiling_assets
+    root = build_project
+    project = BoringBuilder::Project.new(BoringBuilder::Configuration.new(root: root)).validate!
+    client = RecordingClient.new
+
+    BoringBuilder::RailsBuild.new(project, client).container
+
+    cleanup = client.calls.index([:with_exec, [%w[rm -rf .bundle/cache]], {}])
+    assets = client.calls.index([:with_exec, [%w[bin/rails assets:precompile]], {}])
+
+    assert_operator cleanup, :<, assets
+  end
+
   def test_keeps_build_packages_out_of_the_runtime_stage
     root = build_project
     project = BoringBuilder::Project.new(BoringBuilder::Configuration.new(root: root)).validate!