Use serverUrl from the image as a fallback for the Credentials helper

Before this commit, the credential helper incorrectly used
the `serverUrl` from the `auths` if present. However, the helper only
uses the `email` from the `auths`, while the `serverUrl` is used either
from the helper's response or directly from the image's `serverUrl`.

Signed-off-by: Dmytro Nosan <[email protected]>

Author: nosan

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

@@ -85,14 +85,13 @@ private String getServerUrl(ImageReference imageReference) {
 	private DockerRegistryAuthentication getAuthentication(String serverUrl) {
 		Credential credentialsFromHelper = getCredentialsFromHelper(serverUrl);
 		Map.Entry<String, Auth> authConfigEntry = getAuthConfigEntry(serverUrl);
-		serverUrl = (authConfigEntry != null) ? authConfigEntry.getKey() : serverUrl;
 		Auth authConfig = (authConfigEntry != null) ? authConfigEntry.getValue() : null;
 		if (credentialsFromHelper != null) {
 			return getAuthentication(credentialsFromHelper, authConfig, serverUrl);
 		}
-		if (authConfigEntry != null) {
-			return DockerRegistryAuthentication.user(authConfig.getUsername(), authConfig.getPassword(), serverUrl,
-					authConfig.getEmail());
+		if (authConfig != null) {
+			return DockerRegistryAuthentication.user(authConfig.getUsername(), authConfig.getPassword(),
+					authConfigEntry.getKey(), authConfig.getEmail());
 		}
 		return this.fallback;
 	}

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

@@ -348,6 +348,36 @@ void getAuthHeaderReturnsFallbackWhenImageReferenceNull(@ResourcesRoot Path dire
 		then(desktopHelper).should(never()).get(any(String.class));
 	}
 
+	@WithResource(name = "config.json", content = """
+			{
+			  "auths": {
+			    "https://my-registry.example.com": {
+			      "email": "[email protected]"
+			    }
+			  },
+			  "credsStore": "desktop"
+			}
+			""")
+	@WithResource(name = "credentials.json", content = """
+			{
+			  "Username": "username",
+			  "Secret": "secret"
+			}
+			""")
+	@Test
+	void getAuthHeaderWhenUsingHelperFromCredHelpersUsesImageReferenceServerUrlAsFallback(@ResourcesRoot Path directory)
+			throws Exception {
+		this.environment.put("DOCKER_CONFIG", directory.toString());
+		mockHelper("desktop", "my-registry.example.com", "credentials.json");
+		ImageReference imageReference = ImageReference.of("my-registry.example.com/ubuntu:latest");
+		String authHeader = getAuthHeader(imageReference);
+		assertThat(decode(authHeader)).hasSize(4)
+			.containsEntry("serveraddress", "my-registry.example.com")
+			.containsEntry("username", "username")
+			.containsEntry("password", "secret")
+			.containsEntry("email", "[email protected]");
+	}
+
 	private String getAuthHeader(ImageReference imageReference) {
 		return getAuthHeader(imageReference, null);
 	}