Added support for argument file provided by Spring Boot for native bu…

boot/build.go

@@ -129,6 +129,7 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 		}
 		classpathLayer.Logger = b.Logger
 		result.Layers = append(result.Layers, classpathLayer)
+
 	} else {
 		// contribute Spring Cloud Bindings - false by default
 		if !cr.ResolveBool("BP_SPRING_CLOUD_BINDINGS_DISABLED") {

boot/native_image.go

@@ -17,6 +17,7 @@ package boot
 
 import (
 	"fmt"
+	"github.com/paketo-buildpacks/libpak/sherpa"
 	"os"
 	"path/filepath"
 	"strings"
@@ -65,6 +66,15 @@ func (n NativeImageClasspath) Contribute(layer libcnb.Layer) (libcnb.Layer, erro
 			string(filepath.ListSeparator),
 			strings.Join(cp, string(filepath.ListSeparator)),
 		)
+
+		nativeImageArgFile := filepath.Join(n.ApplicationPath, "META-INF", "native-image", "argfile")
+		if exists, err := sherpa.Exists(nativeImageArgFile); err != nil{
+			return libcnb.Layer{}, fmt.Errorf("unable to check for native-image arguments file at %s\n%w", nativeImageArgFile, err)
+		} else if exists{
+			lc.Logger.Bodyf(fmt.Sprintf("native args file %s", nativeImageArgFile))
+			layer.BuildEnvironment.Default("BP_NATIVE_IMAGE_BUILD_ARGUMENTS_FILE", nativeImageArgFile)
+		}
+
 		return layer, nil
 	})
 }

boot/native_image_test.go

@@ -116,4 +116,24 @@ func testNativeImage(t *testing.T, context spec.G, it spec.S) {
 			Expect(layer.LayerTypes.Launch).To(BeFalse())
 		})
 	})
+	context("Boot @argfile is found", func() {
+		it.Before(func() {
+			Expect(ioutil.WriteFile(filepath.Join(appDir, "BOOT-INF", "classpath.idx"), []byte(`
+- "some.jar"
+- "other.jar"
+`), 0644)).To(Succeed())
+			Expect(os.MkdirAll(filepath.Join(appDir, "META-INF", "native-image"), 0755)).To(Succeed())
+			Expect(ioutil.WriteFile(filepath.Join(appDir, "META-INF", "native-image", "argfile"), []byte("file-data"), 0644)).To(Succeed())
+		})
+
+		it("ensures BP_NATIVE_IMAGE_BUILD_ARGUMENTS_FILE is set when argfile is found", func() {
+			layer, err := contributor.Contribute(layer)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(layer.BuildEnvironment["BP_NATIVE_IMAGE_BUILD_ARGUMENTS_FILE.default"]).To(Equal(
+				filepath.Join(appDir, "META-INF", "native-image", "argfile")))
+			Expect(layer.LayerTypes.Build).To(BeTrue())
+			Expect(layer.LayerTypes.Launch).To(BeFalse())
+		})
+	})
 }