Merge branch '2.7.x'

Closes gh-31559

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/Builder.java

@@ -107,7 +107,8 @@ public class Builder {
 		Image runImage = imageFetcher.fetchImage(ImageType.RUNNER, request.getRunImage());
 		assertStackIdsMatch(runImage, builderImage);
 		BuildOwner buildOwner = BuildOwner.fromEnv(builderImage.getConfig().getEnv());
-		Buildpacks buildpacks = getBuildpacks(request, imageFetcher, builderMetadata);
+		BuildpackLayersMetadata buildpackLayersMetadata = BuildpackLayersMetadata.fromImage(builderImage);
+		Buildpacks buildpacks = getBuildpacks(request, imageFetcher, builderMetadata, buildpackLayersMetadata);
 		EphemeralBuilder ephemeralBuilder = new EphemeralBuilder(buildOwner, builderImage, request.getName(),
 				builderMetadata, request.getCreator(), request.getEnv(), buildpacks);
 		this.docker.image().load(ephemeralBuilder.getArchive(), UpdateListener.none());
@@ -143,8 +144,10 @@ public class Builder {
 				+ "' does not match builder stack '" + builderImageStackId + "'");
 	}
 
-	private Buildpacks getBuildpacks(BuildRequest request, ImageFetcher imageFetcher, BuilderMetadata builderMetadata) {
-		BuildpackResolverContext resolverContext = new BuilderResolverContext(imageFetcher, builderMetadata);
+	private Buildpacks getBuildpacks(BuildRequest request, ImageFetcher imageFetcher, BuilderMetadata builderMetadata,
+			BuildpackLayersMetadata buildpackLayersMetadata) {
+		BuildpackResolverContext resolverContext = new BuilderResolverContext(imageFetcher, builderMetadata,
+				buildpackLayersMetadata);
 		return BuildpackResolvers.resolveAll(resolverContext, request.getBuildpacks());
 	}
 
@@ -245,9 +248,13 @@ public class Builder {
 
 		private final BuilderMetadata builderMetadata;
 
-		BuilderResolverContext(ImageFetcher imageFetcher, BuilderMetadata builderMetadata) {
+		private final BuildpackLayersMetadata buildpackLayersMetadata;
+
+		BuilderResolverContext(ImageFetcher imageFetcher, BuilderMetadata builderMetadata,
+				BuildpackLayersMetadata buildpackLayersMetadata) {
 			this.imageFetcher = imageFetcher;
 			this.builderMetadata = builderMetadata;
+			this.buildpackLayersMetadata = buildpackLayersMetadata;
 		}
 
 		@Override
@@ -255,6 +262,11 @@ public class Builder {
 			return this.builderMetadata.getBuildpacks();
 		}
 
+		@Override
+		public BuildpackLayersMetadata getBuildpackLayersMetadata() {
+			return this.buildpackLayersMetadata;
+		}
+
 		@Override
 		public Image fetchImage(ImageReference reference, ImageType imageType) throws IOException {
 			return this.imageFetcher.fetchImage(imageType, reference);

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/BuildpackLayersMetadata.java

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2012-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.buildpack.platform.build;
+
+import java.io.IOException;
+import java.lang.invoke.MethodHandles;
+import java.util.HashMap;
+import java.util.Map;
+
+import com.fasterxml.jackson.databind.JsonNode;
+
+import org.springframework.boot.buildpack.platform.docker.type.Image;
+import org.springframework.boot.buildpack.platform.docker.type.ImageConfig;
+import org.springframework.boot.buildpack.platform.json.MappedObject;
+import org.springframework.boot.buildpack.platform.json.SharedObjectMapper;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Buildpack layers metadata information.
+ *
+ * @author Scott Frederick
+ */
+final class BuildpackLayersMetadata extends MappedObject {
+
+	private static final String LABEL_NAME = "io.buildpacks.buildpack.layers";
+
+	private final Buildpacks buildpacks;
+
+	private BuildpackLayersMetadata(JsonNode node) {
+		super(node, MethodHandles.lookup());
+		this.buildpacks = Buildpacks.fromJson(getNode());
+	}
+
+	/**
+	 * Return the metadata details of a buildpack with the given ID and version.
+	 * @param id the buildpack ID
+	 * @param version the buildpack version
+	 * @return the buildpack details or {@code null} if a buildpack with the given ID and
+	 * version does not exist in the metadata
+	 */
+	BuildpackLayerDetails getBuildpack(String id, String version) {
+		return this.buildpacks.getBuildpack(id, version);
+	}
+
+	/**
+	 * Create a {@link BuildpackLayersMetadata} from an image.
+	 * @param image the source image
+	 * @return the buildpack layers metadata
+	 * @throws IOException on IO error
+	 */
+	static BuildpackLayersMetadata fromImage(Image image) throws IOException {
+		Assert.notNull(image, "Image must not be null");
+		return fromImageConfig(image.getConfig());
+	}
+
+	/**
+	 * Create a {@link BuildpackLayersMetadata} from image config.
+	 * @param imageConfig the source image config
+	 * @return the buildpack layers metadata
+	 * @throws IOException on IO error
+	 */
+	static BuildpackLayersMetadata fromImageConfig(ImageConfig imageConfig) throws IOException {
+		Assert.notNull(imageConfig, "ImageConfig must not be null");
+		String json = imageConfig.getLabels().get(LABEL_NAME);
+		Assert.notNull(json, () -> "No '" + LABEL_NAME + "' label found in image config labels '"
+				+ StringUtils.collectionToCommaDelimitedString(imageConfig.getLabels().keySet()) + "'");
+		return fromJson(json);
+	}
+
+	/**
+	 * Create a {@link BuildpackLayersMetadata} from JSON.
+	 * @param json the source JSON
+	 * @return the buildpack layers metadata
+	 * @throws IOException on IO error
+	 */
+	static BuildpackLayersMetadata fromJson(String json) throws IOException {
+		return fromJson(SharedObjectMapper.get().readTree(json));
+	}
+
+	/**
+	 * Create a {@link BuildpackLayersMetadata} from JSON.
+	 * @param node the source JSON
+	 * @return the buildpack layers metadata
+	 */
+	static BuildpackLayersMetadata fromJson(JsonNode node) {
+		return new BuildpackLayersMetadata(node);
+	}
+
+	private static class Buildpacks {
+
+		private final Map<String, BuildpackVersions> buildpacks = new HashMap<>();
+
+		private BuildpackLayerDetails getBuildpack(String id, String version) {
+			if (this.buildpacks.containsKey(id)) {
+				return this.buildpacks.get(id).getBuildpack(version);
+			}
+			return null;
+		}
+
+		private void addBuildpackVersions(String id, BuildpackVersions versions) {
+			this.buildpacks.put(id, versions);
+		}
+
+		private static Buildpacks fromJson(JsonNode node) {
+			Buildpacks buildpacks = new Buildpacks();
+			node.fields().forEachRemaining((field) -> buildpacks.addBuildpackVersions(field.getKey(),
+					BuildpackVersions.fromJson(field.getValue())));
+			return buildpacks;
+		}
+
+	}
+
+	private static class BuildpackVersions {
+
+		private final Map<String, BuildpackLayerDetails> versions = new HashMap<>();
+
+		private BuildpackLayerDetails getBuildpack(String version) {
+			return this.versions.get(version);
+		}
+
+		private void addBuildpackVersion(String version, BuildpackLayerDetails details) {
+			this.versions.put(version, details);
+		}
+
+		private static BuildpackVersions fromJson(JsonNode node) {
+			BuildpackVersions versions = new BuildpackVersions();
+			node.fields().forEachRemaining((field) -> versions.addBuildpackVersion(field.getKey(),
+					BuildpackLayerDetails.fromJson(field.getValue())));
+			return versions;
+		}
+
+	}
+
+	static final class BuildpackLayerDetails extends MappedObject {
+
+		private final String name;
+
+		private final String homepage;
+
+		private final String layerDiffId;
+
+		private BuildpackLayerDetails(JsonNode node) {
+			super(node, MethodHandles.lookup());
+			this.name = valueAt("/name", String.class);
+			this.homepage = valueAt("/homepage", String.class);
+			this.layerDiffId = valueAt("/layerDiffID", String.class);
+		}
+
+		/**
+		 * Return the buildpack name.
+		 * @return the name
+		 */
+		String getName() {
+			return this.name;
+		}
+
+		/**
+		 * Return the buildpack homepage address.
+		 * @return the homepage address
+		 */
+		String getHomepage() {
+			return this.homepage;
+		}
+
+		/**
+		 * Return the buildpack layer {@code diffID}.
+		 * @return the layer {@code diffID}
+		 */
+		String getLayerDiffId() {
+			return this.layerDiffId;
+		}
+
+		private static BuildpackLayerDetails fromJson(JsonNode node) {
+			return new BuildpackLayerDetails(node);
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/BuildpackResolverContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,8 @@ interface BuildpackResolverContext {
 
 	List<BuildpackMetadata> getBuildpackMetadata();
 
+	BuildpackLayersMetadata getBuildpackLayersMetadata();
+
 	/**
 	 * Retrieve an image.
 	 * @param reference the image reference

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/ImageBuildpack.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,10 +28,12 @@ import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
 import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
 
+import org.springframework.boot.buildpack.platform.build.BuildpackLayersMetadata.BuildpackLayerDetails;
 import org.springframework.boot.buildpack.platform.docker.transport.DockerEngineException;
 import org.springframework.boot.buildpack.platform.docker.type.Image;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.docker.type.Layer;
+import org.springframework.boot.buildpack.platform.docker.type.LayerId;
 import org.springframework.boot.buildpack.platform.io.IOConsumer;
 import org.springframework.boot.buildpack.platform.io.TarArchive;
 import org.springframework.util.StreamUtils;
@@ -59,13 +61,28 @@ final class ImageBuildpack implements Buildpack {
 			Image image = context.fetchImage(reference, ImageType.BUILDPACK);
 			BuildpackMetadata buildpackMetadata = BuildpackMetadata.fromImage(image);
 			this.coordinates = BuildpackCoordinates.fromBuildpackMetadata(buildpackMetadata);
-			this.exportedLayers = new ExportedLayers(context, reference);
+			if (!buildpackExistsInBuilder(context, image.getLayers())) {
+				this.exportedLayers = new ExportedLayers(context, reference);
+			}
+			else {
+				this.exportedLayers = null;
+			}
 		}
 		catch (IOException | DockerEngineException ex) {
 			throw new IllegalArgumentException("Error pulling buildpack image '" + reference + "'", ex);
 		}
 	}
 
+	private boolean buildpackExistsInBuilder(BuildpackResolverContext context, List<LayerId> imageLayers) {
+		BuildpackLayerDetails buildpackLayerDetails = context.getBuildpackLayersMetadata()
+				.getBuildpack(this.coordinates.getId(), this.coordinates.getVersion());
+		if (buildpackLayerDetails != null) {
+			String layerDiffId = buildpackLayerDetails.getLayerDiffId();
+			return imageLayers.stream().map(LayerId::toString).anyMatch((layerId) -> layerId.equals(layerDiffId));
+		}
+		return false;
+	}
+
 	@Override
 	public BuildpackCoordinates getCoordinates() {
 		return this.coordinates;
@@ -73,7 +90,9 @@ final class ImageBuildpack implements Buildpack {
 
 	@Override
 	public void apply(IOConsumer<Layer> layers) throws IOException {
-		this.exportedLayers.apply(layers);
+		if (this.exportedLayers != null) {
+			this.exportedLayers.apply(layers);
+		}
 	}
 
 	/**

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/BuildpackLayersMetadataTests.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2012-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.buildpack.platform.build;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.buildpack.platform.docker.type.Image;
+import org.springframework.boot.buildpack.platform.docker.type.ImageConfig;
+import org.springframework.boot.buildpack.platform.json.AbstractJsonTests;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link BuildpackLayersMetadata}.
+ *
+ * @author Scott Frederick
+ */
+class BuildpackLayersMetadataTests extends AbstractJsonTests {
+
+	@Test
+	void fromImageLoadsMetadata() throws IOException {
+		Image image = Image.of(getContent("buildpack-image.json"));
+		BuildpackLayersMetadata metadata = BuildpackLayersMetadata.fromImage(image);
+		assertThat(metadata.getBuildpack("example/hello-moon", "0.0.3")).extracting("homepage", "layerDiffId")
+				.containsExactly("https://github.com/example/tree/main/buildpacks/hello-moon",
+						"sha256:4bfdc8714aee68da6662c43bc28d3b41202c88e915641c356523dabe729814c2");
+		assertThat(metadata.getBuildpack("example/hello-world", "0.0.2")).extracting("homepage", "layerDiffId")
+				.containsExactly("https://github.com/example/tree/main/buildpacks/hello-world",
+						"sha256:f752fe099c846e501bdc991d1a22f98c055ddc62f01cfc0495fff2c69f8eb940");
+		assertThat(metadata.getBuildpack("example/hello-world", "version-does-not-exist")).isNull();
+		assertThat(metadata.getBuildpack("id-does-not-exist", "9.9.9")).isNull();
+	}
+
+	@Test
+	void fromImageWhenImageIsNullThrowsException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> BuildpackLayersMetadata.fromImage(null))
+				.withMessage("Image must not be null");
+	}
+
+	@Test
+	void fromImageWhenImageConfigIsNullThrowsException() {
+		Image image = mock(Image.class);
+		assertThatIllegalArgumentException().isThrownBy(() -> BuildpackLayersMetadata.fromImage(image))
+				.withMessage("ImageConfig must not be null");
+	}
+
+	@Test
+	void fromImageConfigWhenLabelIsMissingThrowsException() {
+		Image image = mock(Image.class);
+		ImageConfig imageConfig = mock(ImageConfig.class);
+		given(image.getConfig()).willReturn(imageConfig);
+		given(imageConfig.getLabels()).willReturn(Collections.singletonMap("alpha", "a"));
+		assertThatIllegalArgumentException().isThrownBy(() -> BuildpackLayersMetadata.fromImage(image))
+				.withMessage("No 'io.buildpacks.buildpack.layers' label found in image config labels 'alpha'");
+	}
+
+	@Test
+	void fromJsonLoadsMetadata() throws IOException {
+		BuildpackLayersMetadata metadata = BuildpackLayersMetadata
+				.fromJson(getContentAsString("buildpack-layers-metadata.json"));
+		assertThat(metadata.getBuildpack("example/hello-moon", "0.0.3")).extracting("name", "homepage", "layerDiffId")
+				.containsExactly("Example hello-moon buildpack",
+						"https://github.com/example/tree/main/buildpacks/hello-moon",
+						"sha256:4bfdc8714aee68da6662c43bc28d3b41202c88e915641c356523dabe729814c2");
+		assertThat(metadata.getBuildpack("example/hello-world", "0.0.1")).extracting("name", "homepage", "layerDiffId")
+				.containsExactly("Example hello-world buildpack",
+						"https://github.com/example/tree/main/buildpacks/hello-world",
+						"sha256:1c90e0b80d92555a0523c9ee6500845328fc39ba9dca9d30a877ff759ffbff28");
+		assertThat(metadata.getBuildpack("example/hello-world", "0.0.2")).extracting("name", "homepage", "layerDiffId")
+				.containsExactly("Example hello-world buildpack",
+						"https://github.com/example/tree/main/buildpacks/hello-world",
+						"sha256:f752fe099c846e501bdc991d1a22f98c055ddc62f01cfc0495fff2c69f8eb940");
+		assertThat(metadata.getBuildpack("example/hello-world", "version-does-not-exist")).isNull();
+		assertThat(metadata.getBuildpack("id-does-not-exist", "9.9.9")).isNull();
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/BuildpackResolversTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -84,6 +84,7 @@ class BuildpackResolversTests extends AbstractJsonTests {
 	void resolveAllWithImageBuildpackReferenceReturnsExpectedBuildpack() throws IOException {
 		Image image = Image.of(getContent("buildpack-image.json"));
 		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata()).willReturn(BuildpackLayersMetadata.fromJson("{}"));
 		given(resolverContext.fetchImage(any(), any())).willReturn(image);
 		BuildpackReference reference = BuildpackReference.of("docker://example/buildpack1:latest");
 		Buildpacks buildpacks = BuildpackResolvers.resolveAll(resolverContext, Collections.singleton(reference));

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/ImageBuildpackTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,29 +64,31 @@ class ImageBuildpackTests extends AbstractJsonTests {
 	}
 
 	@Test
-	void resolveWhenFullyQualifiedReferenceReturnsBuilder() throws Exception {
+	void resolveWhenFullyQualifiedReferenceReturnsBuildpack() throws Exception {
 		Image image = Image.of(getContent("buildpack-image.json"));
 		ImageReference imageReference = ImageReference.of("example/buildpack1:1.0.0");
 		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata()).willReturn(BuildpackLayersMetadata.fromJson("{}"));
 		given(resolverContext.fetchImage(eq(imageReference), eq(ImageType.BUILDPACK))).willReturn(image);
 		willAnswer(this::withMockLayers).given(resolverContext).exportImageLayers(eq(imageReference), any());
 		BuildpackReference reference = BuildpackReference.of("docker://example/buildpack1:1.0.0");
 		Buildpack buildpack = ImageBuildpack.resolve(resolverContext, reference);
 		assertThat(buildpack.getCoordinates()).hasToString("example/hello-universe@0.0.1");
-		assertHasExpectedLayers(buildpack);
+		assertAppliesExpectedLayers(buildpack);
 	}
 
 	@Test
-	void resolveWhenUnqualifiedReferenceReturnsBuilder() throws Exception {
+	void resolveWhenUnqualifiedReferenceReturnsBuildpack() throws Exception {
 		Image image = Image.of(getContent("buildpack-image.json"));
 		ImageReference imageReference = ImageReference.of("example/buildpack1:1.0.0");
 		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata()).willReturn(BuildpackLayersMetadata.fromJson("{}"));
 		given(resolverContext.fetchImage(eq(imageReference), eq(ImageType.BUILDPACK))).willReturn(image);
 		willAnswer(this::withMockLayers).given(resolverContext).exportImageLayers(eq(imageReference), any());
 		BuildpackReference reference = BuildpackReference.of("example/buildpack1:1.0.0");
 		Buildpack buildpack = ImageBuildpack.resolve(resolverContext, reference);
 		assertThat(buildpack.getCoordinates()).hasToString("example/hello-universe@0.0.1");
-		assertHasExpectedLayers(buildpack);
+		assertAppliesExpectedLayers(buildpack);
 	}
 
 	@Test
@@ -94,12 +96,13 @@ class ImageBuildpackTests extends AbstractJsonTests {
 		Image image = Image.of(getContent("buildpack-image.json"));
 		ImageReference imageReference = ImageReference.of("example/buildpack1:latest");
 		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata()).willReturn(BuildpackLayersMetadata.fromJson("{}"));
 		given(resolverContext.fetchImage(eq(imageReference), eq(ImageType.BUILDPACK))).willReturn(image);
 		willAnswer(this::withMockLayers).given(resolverContext).exportImageLayers(eq(imageReference), any());
 		BuildpackReference reference = BuildpackReference.of("example/buildpack1");
 		Buildpack buildpack = ImageBuildpack.resolve(resolverContext, reference);
 		assertThat(buildpack.getCoordinates()).hasToString("example/hello-universe@0.0.1");
-		assertHasExpectedLayers(buildpack);
+		assertAppliesExpectedLayers(buildpack);
 	}
 
 	@Test
@@ -108,12 +111,28 @@ class ImageBuildpackTests extends AbstractJsonTests {
 		String digest = "sha256:4acb6bfd6c4f0cabaf7f3690e444afe51f1c7de54d51da7e63fac709c56f1c30";
 		ImageReference imageReference = ImageReference.of("example/buildpack1@" + digest);
 		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata()).willReturn(BuildpackLayersMetadata.fromJson("{}"));
 		given(resolverContext.fetchImage(eq(imageReference), eq(ImageType.BUILDPACK))).willReturn(image);
 		willAnswer(this::withMockLayers).given(resolverContext).exportImageLayers(eq(imageReference), any());
 		BuildpackReference reference = BuildpackReference.of("example/buildpack1@" + digest);
 		Buildpack buildpack = ImageBuildpack.resolve(resolverContext, reference);
 		assertThat(buildpack.getCoordinates()).hasToString("example/hello-universe@0.0.1");
-		assertHasExpectedLayers(buildpack);
+		assertAppliesExpectedLayers(buildpack);
+	}
+
+	@Test
+	void resolveWhenBuildpackExistsInBuilderSkipsLayers() throws Exception {
+		Image image = Image.of(getContent("buildpack-image.json"));
+		ImageReference imageReference = ImageReference.of("example/buildpack1:1.0.0");
+		BuildpackResolverContext resolverContext = mock(BuildpackResolverContext.class);
+		given(resolverContext.getBuildpackLayersMetadata())
+				.willReturn(BuildpackLayersMetadata.fromJson(getContentAsString("buildpack-layers-metadata.json")));
+		given(resolverContext.fetchImage(eq(imageReference), eq(ImageType.BUILDPACK))).willReturn(image);
+		willAnswer(this::withMockLayers).given(resolverContext).exportImageLayers(eq(imageReference), any());
+		BuildpackReference reference = BuildpackReference.of("docker://example/buildpack1:1.0.0");
+		Buildpack buildpack = ImageBuildpack.resolve(resolverContext, reference);
+		assertThat(buildpack.getCoordinates()).hasToString("example/hello-universe@0.0.1");
+		assertAppliesNoLayers(buildpack);
 	}
 
 	@Test
@@ -181,7 +200,7 @@ class ImageBuildpackTests extends AbstractJsonTests {
 		tarOut.closeArchiveEntry();
 	}
 
-	private void assertHasExpectedLayers(Buildpack buildpack) throws IOException {
+	private void assertAppliesExpectedLayers(Buildpack buildpack) throws IOException {
 		List<ByteArrayOutputStream> layers = new ArrayList<>();
 		buildpack.apply((layer) -> {
 			ByteArrayOutputStream out = new ByteArrayOutputStream();
@@ -208,4 +227,14 @@ class ImageBuildpackTests extends AbstractJsonTests {
 						TarArchiveEntry.DEFAULT_FILE_MODE));
 	}
 
+	private void assertAppliesNoLayers(Buildpack buildpack) throws IOException {
+		List<ByteArrayOutputStream> layers = new ArrayList<>();
+		buildpack.apply((layer) -> {
+			ByteArrayOutputStream out = new ByteArrayOutputStream();
+			layer.writeTo(out);
+			layers.add(out);
+		});
+		assertThat(layers).isEmpty();
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/resources/org/springframework/boot/buildpack/platform/build/buildpack-layers-metadata.json

@@ -0,0 +1,70 @@
+{
+	"example/hello-moon": {
+		"0.0.3": {
+			"api": "0.2",
+			"stacks": [
+				{
+					"id": "io.buildpacks.stacks.alpine"
+				},
+				{
+					"id": "io.buildpacks.stacks.bionic"
+				}
+			],
+            "name": "Example hello-moon buildpack",
+			"layerDiffID": "sha256:4bfdc8714aee68da6662c43bc28d3b41202c88e915641c356523dabe729814c2",
+			"homepage": "https://github.com/example/tree/main/buildpacks/hello-moon"
+		}
+	},
+	"example/hello-universe": {
+		"0.0.1": {
+			"api": "0.2",
+			"order": [
+				{
+					"group": [
+						{
+							"id": "example/hello-world",
+							"version": "0.0.2"
+						},
+						{
+							"id": "example/hello-moon",
+							"version": "0.0.2"
+						}
+					]
+				}
+			],
+            "name": "Example hello-universe buildpack",
+			"layerDiffID": "sha256:739b4e8f3caae7237584a1bfe029ebdb05403752b1a60a4f9be991b1d51dbb69",
+			"homepage": "https://github.com/example/tree/main/buildpacks/hello-universe"
+		}
+	},
+	"example/hello-world": {
+		"0.0.1": {
+			"api": "0.2",
+			"stacks": [
+				{
+					"id": "io.buildpacks.stacks.alpine"
+				},
+				{
+					"id": "io.buildpacks.stacks.bionic"
+				}
+			],
+            "name": "Example hello-world buildpack",
+			"layerDiffID": "sha256:1c90e0b80d92555a0523c9ee6500845328fc39ba9dca9d30a877ff759ffbff28",
+			"homepage": "https://github.com/example/tree/main/buildpacks/hello-world"
+		},
+		"0.0.2": {
+			"api": "0.2",
+			"stacks": [
+				{
+					"id": "io.buildpacks.stacks.alpine"
+				},
+				{
+					"id": "io.buildpacks.stacks.bionic"
+				}
+			],
+            "name": "Example hello-world buildpack",
+			"layerDiffID": "sha256:f752fe099c846e501bdc991d1a22f98c055ddc62f01cfc0495fff2c69f8eb940",
+			"homepage": "https://github.com/example/tree/main/buildpacks/hello-world"
+		}
+	}
+}