Merge pull request #45291 from nosan

* pr/45291:
  Polish

Closes gh-45291

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/configuration/Credential.java

@@ -40,7 +40,7 @@ class Credential extends MappedObject {
 
 	private final String secret;
 
-	private String serverUrl;
+	private final String serverUrl;
 
 	Credential(JsonNode node) {
 		super(node, MethodHandles.lookup());

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/configuration/CredentialHelper.java

@@ -39,7 +39,7 @@ class CredentialHelper {
 
 	private static final String USR_LOCAL_BIN = "/usr/local/bin/";
 
-	Set<String> CREDENTIAL_NOT_FOUND_MESSAGES = Set.of("credentials not found in native keychain",
+	private static final Set<String> CREDENTIAL_NOT_FOUND_MESSAGES = Set.of("credentials not found in native keychain",
 			"no credentials server URL", "no credentials username");
 
 	private final String executable;
@@ -73,12 +73,12 @@ class CredentialHelper {
 		}
 	}
 
-	private ProcessBuilder processBuilder(String string) {
+	private ProcessBuilder processBuilder(String action) {
 		ProcessBuilder processBuilder = new ProcessBuilder().redirectErrorStream(true);
 		if (Platform.isWindows()) {
 			processBuilder.command("cmd", "/c");
 		}
-		processBuilder.command(this.executable, string);
+		processBuilder.command(this.executable, action);
 		return processBuilder;
 	}
 
@@ -90,14 +90,21 @@ class CredentialHelper {
 			if (!Platform.isMac()) {
 				throw ex;
 			}
-			List<String> command = new ArrayList<>(processBuilder.command());
+			try {
-			command.set(0, USR_LOCAL_BIN + command.get(0));
+				List<String> command = new ArrayList<>(processBuilder.command());
-			return processBuilder.command(command).start();
+				command.set(0, USR_LOCAL_BIN + command.get(0));
+				return processBuilder.command(command).start();
+			}
+			catch (Exception suppressed) {
+				// Suppresses the exception and rethrows the original exception
+				ex.addSuppressed(suppressed);
+				throw ex;
+			}
 		}
 	}
 
-	private boolean isCredentialsNotFoundError(String message) {
+	private static boolean isCredentialsNotFoundError(String message) {
-		return this.CREDENTIAL_NOT_FOUND_MESSAGES.contains(message.trim());
+		return CREDENTIAL_NOT_FOUND_MESSAGES.contains(message.trim());
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/configuration/DockerConfigurationMetadata.java

@@ -26,6 +26,7 @@ import java.security.NoSuchAlgorithmException;
 import java.util.Base64;
 import java.util.HexFormat;
 import java.util.Map;
+import java.util.function.Supplier;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
@@ -36,6 +37,7 @@ import org.springframework.boot.buildpack.platform.json.SharedObjectMapper;
 import org.springframework.boot.buildpack.platform.system.Environment;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
+import org.springframework.util.function.SingletonSupplier;
 
 /**
  * Docker configuration stored in metadata files managed by the Docker CLI.
@@ -63,7 +65,8 @@ final class DockerConfigurationMetadata {
 
 	private static final String CONTEXT_FILE_NAME = "meta.json";
 
-	private static volatile DockerConfigurationMetadata systemEnvironmentConfigurationMetadata;
+	private static final Supplier<DockerConfigurationMetadata> systemEnvironmentConfigurationMetadata = SingletonSupplier
+		.of(() -> DockerConfigurationMetadata.create(Environment.SYSTEM));
 
 	private final String configLocation;
 
@@ -90,20 +93,18 @@ final class DockerConfigurationMetadata {
 	}
 
 	static DockerConfigurationMetadata from(Environment environment) {
-		DockerConfigurationMetadata dockerConfigurationMetadata = (environment == Environment.SYSTEM)
+		if (environment == Environment.SYSTEM) {
-				? DockerConfigurationMetadata.systemEnvironmentConfigurationMetadata : null;
+			return systemEnvironmentConfigurationMetadata.get();
-		if (dockerConfigurationMetadata != null) {
-			return dockerConfigurationMetadata;
 		}
+		return create(environment);
+	}
+
+	private static DockerConfigurationMetadata create(Environment environment) {
 		String configLocation = environment.get(DOCKER_CONFIG);
 		configLocation = (configLocation != null) ? configLocation : getUserHomeConfigLocation();
 		DockerConfig dockerConfig = createDockerConfig(configLocation);
 		DockerContext dockerContext = createDockerContext(configLocation, dockerConfig.getCurrentContext());
-		dockerConfigurationMetadata = new DockerConfigurationMetadata(configLocation, dockerConfig, dockerContext);
+		return new DockerConfigurationMetadata(configLocation, dockerConfig, dockerContext);
-		if (environment == Environment.SYSTEM) {
-			DockerConfigurationMetadata.systemEnvironmentConfigurationMetadata = dockerConfigurationMetadata;
-		}
-		return dockerConfigurationMetadata;
 	}
 
 	private static String getUserHomeConfigLocation() {

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/configuration/DockerRegistryAuthentication.java

@@ -19,6 +19,7 @@ package org.springframework.boot.buildpack.platform.docker.configuration;
 import java.util.function.BiConsumer;
 
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
+import org.springframework.util.Assert;
 
 /**
  * Docker registry authentication configuration.
@@ -83,7 +84,8 @@ public interface DockerRegistryAuthentication {
 	 * Factory method that returns a new {@link DockerRegistryAuthentication} instance
 	 * that uses the standard docker JSON config (including support for credential
 	 * helpers) to generate auth headers.
-	 * @param fallback the fallback authentication to use if no suitable config is found
+	 * @param fallback the fallback authentication to use if no suitable config is found,
+	 * may be null {@code}
 	 * @return a new {@link DockerRegistryAuthentication} instance
 	 * @since 3.5.0
 	 * @see #configuration(DockerRegistryAuthentication, BiConsumer)
@@ -96,15 +98,17 @@ public interface DockerRegistryAuthentication {
 	 * Factory method that returns a new {@link DockerRegistryAuthentication} instance
 	 * that uses the standard docker JSON config (including support for credential
 	 * helpers) to generate auth headers.
-	 * @param fallback the fallback authentication to use if no suitable config is found
+	 * @param fallback the fallback authentication to use if no suitable config is found,
+	 * may be {@code null}
 	 * @param credentialHelperExceptionHandler callback that should handle credential
-	 * helper exceptions
+	 * helper exceptions, never {@code null}
 	 * @return a new {@link DockerRegistryAuthentication} instance
 	 * @since 3.5.0
 	 * @see #configuration(DockerRegistryAuthentication, BiConsumer)
 	 */
 	static DockerRegistryAuthentication configuration(DockerRegistryAuthentication fallback,
 			BiConsumer<String, Exception> credentialHelperExceptionHandler) {
+		Assert.notNull(credentialHelperExceptionHandler, () -> "'credentialHelperExceptionHandler' must not be null");
 		return new DockerRegistryConfigAuthentication(fallback, credentialHelperExceptionHandler);
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/configuration/CredentialHelperTests.java

@@ -89,10 +89,17 @@ class CredentialHelperTests {
 	}
 
 	@Test
-	void getWhenCommandDoesNotExistErrorThrowsException() {
+	void getWhenExecutableDoesNotExistErrorThrowsException() {
-		String name = "docker-credential-%s".formatted(UUID.randomUUID().toString());
+		String executable = "docker-credential-%s".formatted(UUID.randomUUID().toString());
-		assertThatIOException().isThrownBy(() -> new CredentialHelper(name).get("invalid.example.com"))
+		assertThatIOException().isThrownBy(() -> new CredentialHelper(executable).get("invalid.example.com"))
-			.withMessageContaining(name);
+			.withMessageContaining(executable)
+			.satisfies((ex) -> {
+				if (Platform.isMac()) {
+					assertThat(ex.getMessage()).doesNotContain("/usr/local/bin/");
+					assertThat(ex.getSuppressed()).allSatisfy((suppressed) -> assertThat(suppressed)
+						.hasMessageContaining("/usr/local/bin/" + executable));
+				}
+			});
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/configuration/CredentialTests.java

@@ -32,7 +32,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Dmytro Nosan
  */
-class CredentialsTests {
+class CredentialTests {
 
 	@Test
 	@WithResource(name = "credentials.json", content = """