Fix bundler 4.x incompatibility and switchblade multi-stack deletion

go.mod

@@ -7,7 +7,7 @@ toolchain go1.24.0
 require (
 	github.com/blang/semver v3.5.1+incompatible
 	github.com/cloudfoundry/libbuildpack v0.0.0-20251202224209-b07cc3dab65e
-	github.com/cloudfoundry/switchblade v0.9.4
+	github.com/cloudfoundry/switchblade v0.9.5
 	github.com/golang/mock v1.6.0
 	github.com/kr/text v0.2.0
 	github.com/onsi/ginkgo v1.16.5

go.sum

@@ -744,8 +744,8 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/cloudflare/circl v1.1.0/go.mod h1:prBCrKB9DV4poKZY1l9zBXg2QJY7mvgRvtMxxK7fi4I=
 github.com/cloudfoundry/libbuildpack v0.0.0-20251202224209-b07cc3dab65e h1:L9bl+eey+J8CQ5Dv24nJ5giUx00gdigZv4ElqzR0uRA=
 github.com/cloudfoundry/libbuildpack v0.0.0-20251202224209-b07cc3dab65e/go.mod h1:kn4FHMwI8bTd9gT92wPGjXHzUvGcj8CkPxG8q3AGBAQ=
-github.com/cloudfoundry/switchblade v0.9.4 h1:93O90a/DRRcZ4h50htDh4z7+FMliqy/lQH6IFgVa+mQ=
-github.com/cloudfoundry/switchblade v0.9.4/go.mod h1:hIEQdGAsuNnzlyQfsD5OIORt38weSBar6Wq5/JX6Omo=
+github.com/cloudfoundry/switchblade v0.9.5 h1:GTga1Uu6kGOL+n1TRTHyZm170N5/B/ou6wU90MiKKys=
+github.com/cloudfoundry/switchblade v0.9.5/go.mod h1:hIEQdGAsuNnzlyQfsD5OIORt38weSBar6Wq5/JX6Omo=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=

src/ruby/supply/supply.go

@@ -9,6 +9,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"strconv"
 	"strings"
 
 	"github.com/cloudfoundry/libbuildpack"
@@ -323,11 +324,11 @@ func (s *Supplier) InstallBundler() error {
 		matches = []string{"", "2"}
 	}
 
-	if strings.HasPrefix(matches[1], "2") {
-		return s.installBundler("2.x.x")
+	if strings.HasPrefix(matches[1], "1") {
+		return s.installBundler("1.x.x")
 	}
 
-	return s.installBundler("1.x.x")
+	return s.installBundler("2.x.x")
 }
 
 func (s *Supplier) InstallNode() error {
@@ -468,7 +469,7 @@ func (s *Supplier) VendorBundlePath() (string, error) {
 		return "", err
 	}
 
-	if strings.HasPrefix(bundlerVersion, "2.") {
+	if !strings.HasPrefix(bundlerVersion, "1.") {
 		return "vendor_bundle", nil
 	}
 
@@ -610,6 +611,17 @@ func (s *Supplier) UpdateRubygems() error {
 		return fmt.Errorf("Could not install rubygems: %v", err)
 	}
 
+	// Rubygems 4.x ships bundler 4.x as a default gem. Running setup.rb
+	// overwrites the buildpack-installed bundler (2.x) with bundler 4.x,
+	// which has incompatible output format changes and untested behavior.
+	// Re-install the buildpack's bundler to restore the manifest version.
+	if majorVersion, err := strconv.Atoi(strings.SplitN(dep.Version, ".", 2)[0]); err == nil && majorVersion >= 4 {
+		s.Log.Debug("Re-installing bundler after rubygems %s update", dep.Version)
+		if err := s.InstallBundler(); err != nil {
+			return fmt.Errorf("Could not re-install bundler after rubygems update: %v", err)
+		}
+	}
+
 	return nil
 }
 
@@ -739,7 +751,7 @@ func (s *Supplier) InstallGems() error {
 			return fmt.Errorf("could not read Bundled With version from gemfile.lock: %s", err)
 		}
 
-		if bundledWithVersion != bundlerVersion && strings.HasPrefix(bundledWithVersion, "2") {
+		if bundledWithVersion != bundlerVersion && !strings.HasPrefix(bundledWithVersion, "1") {
 			if err := s.removeIncompatibleBundledWithVersion(bundledWithVersion); err != nil {
 				return fmt.Errorf("could not remove Bundled With from end of "+
 					"gemfile.lock: %s", err)

src/ruby/supply/supply_test.go

@@ -68,7 +68,7 @@ var _ = Describe("Supply", func() {
 		mockCtrl = gomock.NewController(GinkgoT())
 
 		mockManifest = NewMockManifest(mockCtrl)
-		mockManifest.EXPECT().AllDependencyVersions("bundler").Return([]string{"1.17.2"}).AnyTimes()
+		mockManifest.EXPECT().AllDependencyVersions("bundler").Return([]string{"1.17.2", "2.7.2"}).AnyTimes()
 
 		mockInstaller = NewMockInstaller(mockCtrl)
 
@@ -133,6 +133,28 @@ var _ = Describe("Supply", func() {
 		})
 	})
 
+	Describe("InstallBundler with bundler 2.x BUNDLED WITH", func() {
+
+		var tempSupplier supply.Supplier
+
+		BeforeEach(func() {
+			tempSupplier = *supplier
+			mockStager := NewMockStager(mockCtrl)
+			tempSupplier.Stager = mockStager
+
+			mockInstaller.EXPECT().InstallDependency(libbuildpack.Dependency{Name: "bundler", Version: "2.7.2"}, gomock.Any())
+			mockStager.EXPECT().LinkDirectoryInDepDir(gomock.Any(), gomock.Any())
+			mockStager.EXPECT().DepDir().AnyTimes()
+
+			err := os.WriteFile(filepath.Join(buildDir, "Gemfile.lock"), []byte("BUNDLED WITH\n    2.4.0"), 0644)
+			Expect(err).NotTo(HaveOccurred())
+		})
+
+		It("installs bundler 2.x matching constraint given", func() {
+			Expect(tempSupplier.InstallBundler()).To(Succeed())
+		})
+	})
+
 	Describe("InstallNode", func() {
 		var tempSupplier supply.Supplier
 
@@ -389,6 +411,23 @@ var _ = Describe("Supply", func() {
 				Expect(actualEnv).To(Equal(expectedEnv))
 			})
 		})
+
+		Describe("With Bundler version 4.x.x (future-proofing)", func() {
+			BeforeEach(func() {
+				mockVersions.EXPECT().GetBundlerVersion().Return("4.0.9", nil).AnyTimes()
+
+				mockStager.EXPECT().DepDir().Return("some/test-dir").AnyTimes()
+				mockStager.EXPECT().WriteEnvFile(gomock.Any(), gomock.Any()).Return(nil)
+			})
+
+			It("should use vendor_bundle path like bundler 2.x", func() {
+				Expect(tempSupplier.AddPostRubyGemsInstallDefaultEnv()).To(Succeed())
+
+				expectedEnv := "some/test-dir/vendor_bundle"
+				actualEnv := os.Getenv("BUNDLE_PATH")
+				Expect(actualEnv).To(Equal(expectedEnv))
+			})
+		})
 	})
 
 	Describe("CopyDirToTemp", func() {
@@ -1177,6 +1216,39 @@ var _ = Describe("Supply", func() {
 		})
 	})
 
+	Describe("UpdateRubygems with rubygems >= 4 re-installs bundler", func() {
+		BeforeEach(func() {
+			mockManifest.EXPECT().AllDependencyVersions("rubygems").AnyTimes().Return([]string{"4.0.9"})
+		})
+		Context("gem version is less than 4.0.9", func() {
+			BeforeEach(func() {
+				mockCommand.EXPECT().Output(gomock.Any(), "gem", "--version").AnyTimes().Return("3.4.19\n", nil)
+				mockVersions.EXPECT().VersionConstraint("3.4.19", ">= 4.0.9").AnyTimes().Return(false, nil)
+			})
+
+			It("updates rubygems and re-installs bundler", func() {
+				mockVersions.EXPECT().Engine().Return("ruby", nil)
+				mockInstaller.EXPECT().InstallDependency(gomock.Any(), gomock.Any()).Do(func(dep libbuildpack.Dependency, _ string) {
+					Expect(dep.Name).To(Equal("rubygems"))
+					Expect(dep.Version).To(Equal("4.0.9"))
+				})
+				mockCommand.EXPECT().Output(gomock.Any(), "ruby", "setup.rb")
+
+				// Rubygems >= 4 triggers bundler re-install.
+				// InstallBundler reads Gemfile.lock (not present here, so defaults
+				// to 2.x.x constraint) and installs bundler from the manifest.
+				mockInstaller.EXPECT().InstallDependency(gomock.Any(), gomock.Any()).Do(func(dep libbuildpack.Dependency, installDir string) {
+					Expect(dep.Name).To(Equal("bundler"))
+					Expect(dep.Version).To(Equal("2.7.2"))
+					// Create bin dir so LinkDirectoryInDepDir succeeds
+					Expect(os.MkdirAll(filepath.Join(installDir, "bin"), 0755)).To(Succeed())
+				})
+
+				Expect(supplier.UpdateRubygems()).To(Succeed())
+			})
+		})
+	})
+
 	Describe("RewriteShebangs", func() {
 		var depDir string
 		BeforeEach(func() {

src/ruby/versions/ruby.go

@@ -59,7 +59,9 @@ func (v *Versions) GetBundlerVersion() (string, error) {
 		return "", err
 	}
 
-	re := regexp.MustCompile(`Bundler version (\d+\.\d+\.\d+) .*`)
+	// Bundler 2.x outputs "Bundler version X.Y.Z (...)" but bundler 4.x
+	// omits the "Bundler version" prefix and outputs just "X.Y.Z (...)".
+	re := regexp.MustCompile(`(?:Bundler version )?(\d+\.\d+\.\d+)`)
 	match := re.FindStringSubmatch(stdout.String())
 
 	if len(match) != 2 {
@@ -192,9 +194,11 @@ func (v *Versions) GemMajorVersion(gem string) (int, error) {
 	}
 }
 
-//Should return true if either:
+// Should return true if either:
 // (1) the only platform in the Gemfile.lock is windows (mingw/mswin)
-//     -or-
+//
+//	-or-
+//
 // (2) the Gemfile.lock line endings are /r/n, rather than just /n
 func (v *Versions) HasWindowsGemfileLock() (bool, error) {
 	gemfileLockPath := v.Gemfile() + ".lock"

vendor/modules.txt

@@ -26,7 +26,7 @@ github.com/cloudfoundry/libbuildpack/cutlass
 github.com/cloudfoundry/libbuildpack/cutlass/docker
 github.com/cloudfoundry/libbuildpack/cutlass/glow
 github.com/cloudfoundry/libbuildpack/packager
-# github.com/cloudfoundry/switchblade v0.9.4
+# github.com/cloudfoundry/switchblade v0.9.5
 ## explicit; go 1.23.0
 github.com/cloudfoundry/switchblade
 github.com/cloudfoundry/switchblade/internal/cloudfoundry