Let the last label take precedence in the native repository

docs/modules/ROOT/pages/server/environment-repository/file-system-backend.adoc

@@ -23,3 +23,8 @@ Thus, the default behaviour with no placeholders is the same as adding a search
 For example, `file:/tmp/config` is the same as `file:/tmp/config,file:/tmp/config/\{label}`.
 This behavior can be disabled by setting `spring.cloud.config.server.native.addLabelLocations=false`.
 
+If the request contains several labels (a comma-separated list), the last label takes precedence over the earlier ones, as it does for the Git and SVN backends.
+Each label is resolved on its own, and the locations the labels share come last.
+Before this behavior was introduced, the first label took precedence.
+To restore that behavior, set `spring.cloud.config.server.native.lastLabelWins=false`.
+

spring-cloud-config-server/src/main/java/org/springframework/cloud/config/server/environment/NativeEnvironmentProperties.java

@@ -35,6 +35,13 @@ public class NativeEnvironmentProperties implements EnvironmentRepositoryPropert
 	 */
 	private Boolean addLabelLocations = true;
 
+	/**
+	 * Flag to determine whether, when several labels are requested, the last label takes
+	 * precedence over the earlier ones (default true). If false, the first label takes
+	 * precedence, as it did before this property was introduced.
+	 */
+	private Boolean lastLabelWins = true;
+
 	private String defaultLabel = "master";
 
 	/**
@@ -66,6 +73,14 @@ public void setAddLabelLocations(Boolean addLabelLocations) {
 		this.addLabelLocations = addLabelLocations;
 	}
 
+	public Boolean getLastLabelWins() {
+		return this.lastLabelWins;
+	}
+
+	public void setLastLabelWins(Boolean lastLabelWins) {
+		this.lastLabelWins = lastLabelWins;
+	}
+
 	public String getDefaultLabel() {
 		return this.defaultLabel;
 	}

spring-cloud-config-server/src/main/java/org/springframework/cloud/config/server/environment/NativeEnvironmentRepository.java

@@ -17,10 +17,12 @@
 package org.springframework.cloud.config.server.environment;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -85,6 +87,8 @@ public class NativeEnvironmentRepository implements EnvironmentRepository, Searc
 	 */
 	private boolean addLabelLocations;
 
+	private boolean lastLabelWins = true;
+
 	/**
 	 * Version string to be reported for native repository.
 	 */
@@ -100,6 +104,7 @@ public NativeEnvironmentRepository(ConfigurableEnvironment environment, NativeEn
 			ObservationRegistry observationRegistry) {
 		this.environment = environment;
 		this.addLabelLocations = properties.getAddLabelLocations();
+		this.lastLabelWins = properties.getLastLabelWins();
 		this.defaultLabel = properties.getDefaultLabel();
 		this.failOnError = properties.getFailOnError();
 		this.order = properties.getOrder();
@@ -124,6 +129,14 @@ public void setAddLabelLocations(boolean addLabelLocations) {
 		this.addLabelLocations = addLabelLocations;
 	}
 
+	public boolean isLastLabelWins() {
+		return this.lastLabelWins;
+	}
+
+	public void setLastLabelWins(boolean lastLabelWins) {
+		this.lastLabelWins = lastLabelWins;
+	}
+
 	public String getDefaultLabel() {
 		return this.defaultLabel;
 	}
@@ -139,7 +152,36 @@ public Environment findOne(String config, String profile, String label) {
 
 	@Override
 	public Environment findOne(String config, String profile, String label, boolean includeOrigin) {
+		if (!this.lastLabelWins || label == null || !label.contains(",")) {
+			return findOneForLabel(config, profile, label, includeOrigin);
+		}
+		// Resolve one label at a time, so that the last label takes precedence over the
+		// earlier ones as in the SCM repositories. Resolving them together would let
+		// Spring Boot interleave the labels by profile, giving the first label
+		// precedence.
+		List<String> labels = new ArrayList<>(Arrays.asList(StringUtils.commaDelimitedListToStringArray(label)));
+		Collections.reverse(labels);
+		Environment result = null;
+		Map<String, PropertySource> sources = new LinkedHashMap<>();
+		for (String singleLabel : labels) {
+			Environment environment = findOneForLabel(config, profile, singleLabel, includeOrigin);
+			if (result == null) {
+				result = new Environment(environment.getName(), environment.getProfiles(), label,
+						environment.getVersion(), environment.getState());
+			}
+			for (PropertySource source : environment.getPropertySources()) {
+				// A property source found for several labels comes from a location the
+				// labels share, which has a lower precedence than the label locations,
+				// so keep it at its last position
+				sources.remove(source.getName());
+				sources.put(source.getName(), source);
+			}
+		}
+		sources.values().forEach(result::add);
+		return result;
+	}
 
+	private Environment findOneForLabel(String config, String profile, String label, boolean includeOrigin) {
 		try {
 			ConfigurableEnvironment environment = getEnvironment(config, profile, label);
 			DefaultResourceLoader resourceLoader = new DefaultResourceLoader();

spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/NativeEnvironmentRepositoryTests.java

@@ -261,6 +261,19 @@ public void locationAddLabelLocations() {
 
 	@Test
 	public void locationAddMultipleLabelLocations() {
+		this.repository.setSearchLocations("classpath:/test/dev/");
+		Environment environment = this.repository.findOne("foo", "development", "ignore,applicationxyz");
+		// the last label wins, the location shared by the labels comes last
+		assertThat(environment.getPropertySources()).hasSize(3);
+		assertThat(environment.getPropertySources().get(0).getSource().get("foo")).isEqualTo("default-app");
+		assertThat(environment.getPropertySources().get(1).getSource().get("foo")).isEqualTo("app");
+		assertThat(environment.getPropertySources().get(2).getSource().get("foo")).isEqualTo("dev_bar");
+		assertThat(environment.getLabel()).isEqualTo("ignore,applicationxyz");
+	}
+
+	@Test
+	public void locationAddMultipleLabelLocationsFirstLabelWins() {
+		this.repository.setLastLabelWins(false);
 		this.repository.setSearchLocations("classpath:/test/dev/");
 		Environment environment = this.repository.findOne("foo", "development", "ignore,applicationxyz");
 		assertThat(environment.getPropertySources()).hasSize(3);

spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/compliance/NativeEnvironmentRepositoryComplianceTests.java

@@ -19,8 +19,6 @@
 import java.nio.file.Path;
 
 import io.micrometer.observation.ObservationRegistry;
-import org.junit.jupiter.api.Disabled;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
 import org.springframework.cloud.config.server.environment.EnvironmentRepository;
@@ -57,11 +55,4 @@ public EnvironmentRepository repository() {
 		return this.fixture;
 	}
 
-	@Override
-	@Test
-	@Disabled("TODO-issue: Label directories are added as search locations, so labels are interleaved by profile and the first label wins")
-	public void lastLabelTakesPrecedence() throws Exception {
-		super.lastLabelTakesPrecedence();
-	}
-
 }