Fix property ordering within '.' and '/config'

Allow groups to be used with standard locations so that order of
profile-specific files is consistent.

Prior to this commit, the default search locations considered for
application properties/yaml files was the following:

	optional:classpath:/
	optional:classpath:/config/
	optional:file:./
	optional:file:./config/
	optional:file:./config/*/

Each of these locations was independent which could cause confusion
if certain combinations were used. For example, if profile-specific
files were added to `classpath:/` and `classpath:/config/` then the
latter would always override the former regardless of the profile
ordering.

This commit updates `StandardConfigDataLocationResolver` so that a
group of locations can be specified for each item. This allows us to
define the following set of search locations which provide more logical
ordering for profile-specific files

	optional:classpath:/;optional:classpath:/config/
	optional:file:./;optional:file:./config/;optional:file:./config/*/

Closes gh-26593

spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc

@@ -606,25 +606,29 @@ This means that the JSON cannot override properties from lower order property so
 === External Application Properties [[boot-features-external-config-application-property-files]]
 Spring Boot will automatically find and load `application.properties` and `application.yaml` files from the following locations when your application starts:
 
-. The classpath root
-. The classpath `/config` package
-. The current directory
-. The `/config` subdirectory in the current directory
-. Immediate child directories of the `/config` subdirectory
+. From the classpath
+.. The classpath root
+.. The classpath `/config` package
+. From the current directory
+.. The current directory
+.. The `/config` subdirectory in the current directory
+.. Immediate child directories of the `/config` subdirectory
 
 The list is ordered by precedence (with values from lower items overriding earlier ones).
 Documents from the loaded files are added as `PropertySources` to the Spring `Environment`.
 
 If you do not like `application` as the configuration file name, you can switch to another file name by specifying a configprop:spring.config.name[] environment property.
-You can also refer to an explicit location by using the `spring.config.location` environment property (which is a comma-separated list of directory locations or file paths).
-The following example shows how to specify a different file name:
+For example, to look for `myproject.properties` and `myproject.yaml` files you can run your application as follows:
 
 [indent=0]
 ----
 	$ java -jar myproject.jar --spring.config.name=myproject
 ----
 
-The following example shows how to specify two locations:
+You can also refer to an explicit location by using the configprop:spring.config.location[] environment property.
+This properties accepts a comma-separated list of one or more locations to check.
+
+The following example shows how to specify two distinct files:
 
 [indent=0]
 ----
@@ -636,12 +640,19 @@ TIP: Use the prefix `optional:` if the <<boot-features-external-config-optional-
 WARNING: `spring.config.name`, `spring.config.location`, and `spring.config.additional-location` are used very early to determine which files have to be loaded.
 They must be defined as an environment property (typically an OS environment variable, a system property, or a command-line argument).
 
-If `spring.config.location` contains directories (as opposed to files), they should end in `/` (at runtime they will be appended with the names generated from `spring.config.name` before being loaded).
+If `spring.config.location` contains directories (as opposed to files), they should end in `/`.
+At runtime they will be appended with the names generated from `spring.config.name` before being loaded.
 Files specified in `spring.config.location` are used as-is.
-Whether specified directly or contained in a directory, configuration files must include a file extension in their name.
-Typical extensions that are supported out-of-the-box are `.properties`, `.yaml`, and `.yml`.
 
-When multiple locations are specified, the later ones can override the values of earlier ones.
+In most situations, each configprop:spring.config.location[] item you add will reference a single file or directory.
+Locations are processed in the order that they are defined and later ones can override the values of earlier ones.
+
+[[boot-features-external-config-files-location-groups]]
+If you have a complex location setup, and you use profile-specific configuration files, you may need to provide further hints so that Spring Boot knows how they should be grouped.
+A location group is a collection of locations that are all considered at the same level.
+For example, you might want to group all classpath locations, then all external locations.
+Items within a location group should be separated with `;`.
+See the example in the "`<<boot-features-external-config-files-profile-specific>>`" section for more details.
 
 Locations configured by using `spring.config.location` replace the default locations.
 For example, if `spring.config.location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is:
@@ -653,11 +664,8 @@ If you prefer to add additional locations, rather than replacing them, you can u
 Properties loaded from additional locations can override those in the default locations.
 For example, if `spring.config.additional-location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is:
 
-. `optional:classpath:/`
-. `optional:classpath:/config/`
-. `optional:file:./`
-. `optional:file:./config/`
-. `optional:file:./config/*/`
+. `optional:classpath:/;optional:classpath:/config/`
+. `optional:file:./;optional:file:./config/;optional:file:./config/*/`
 . `optional:classpath:custom-config/`
 . `optional:file:./custom-config/`
 
@@ -718,6 +726,35 @@ Profile-specific properties are loaded from the same locations as standard `appl
 If several profiles are specified, a last-wins strategy applies.
 For example, if profiles `prod,live` are specified by the configprop:spring.profiles.active[] property, values in `application-prod.properties` can be overridden by those in `application-live.properties`.
 
+[NOTE]
+====
+The last-wins strategy applies at the <<boot-features-external-config-files-location-groups,location group>> level.
+A configprop:spring.config.location[] of `classpath:/cfg/,classpath:/ext/` will not have the same override rules as `classpath:/cfg/;classpath:/ext/`.
+
+For example, continuing our `prod,live` example above, we might have the following files:
+
+----
+/cfg
+  application-live.properties
+/ext
+  application-live.properties
+  application-prod.properties
+----
+
+When we have a configprop:spring.config.location[] of `classpath:/cfg/,classpath:/ext/` we process all `/cfg` files before all `/ext` files:
+
+. `/cfg/application-live.properties`
+. `/ext/application-prod.properties`
+. `/ext/application-live.properties`
+
+
+When we have `classpath:/cfg/;classpath:/ext/` instead (with a `;` delimiter) we process `/cfg` and `/ext` at the same level:
+
+. `/ext/application-prod.properties`
+. `/cfg/application-live.properties`
+. `/ext/application-live.properties`
+====
+
 The `Environment` has a set of default profiles (by default, `[default]`) that are used if no active profiles are set.
 In other words, if no profiles are explicitly activated, then properties from `application-default` are considered.
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataEnvironment.java

@@ -87,11 +87,8 @@ class ConfigDataEnvironment {
 	static final ConfigDataLocation[] DEFAULT_SEARCH_LOCATIONS;
 	static {
 		List<ConfigDataLocation> locations = new ArrayList<>();
-		locations.add(ConfigDataLocation.of("optional:classpath:/"));
-		locations.add(ConfigDataLocation.of("optional:classpath:/config/"));
-		locations.add(ConfigDataLocation.of("optional:file:./"));
-		locations.add(ConfigDataLocation.of("optional:file:./config/"));
-		locations.add(ConfigDataLocation.of("optional:file:./config/*/"));
+		locations.add(ConfigDataLocation.of("optional:classpath:/;optional:classpath:/config/"));
+		locations.add(ConfigDataLocation.of("optional:file:./;optional:file:./config/;optional:file:./config/*/"));
 		DEFAULT_SEARCH_LOCATIONS = locations.toArray(new ConfigDataLocation[0]);
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocation.java

@@ -97,6 +97,32 @@ public Origin getOrigin() {
 		return this.origin;
 	}
 
+	/**
+	 * Return an array of {@link ConfigDataLocation} elements built by splitting this
+	 * {@link ConfigDataLocation} around a delimiter of {@code ";"}.
+	 * @return the split locations
+	 * @since 2.4.7
+	 */
+	public ConfigDataLocation[] split() {
+		return split(";");
+	}
+
+	/**
+	 * Return an array of {@link ConfigDataLocation} elements built by splitting this
+	 * {@link ConfigDataLocation} around the specified delimiter.
+	 * @param delimiter the delimiter to split on
+	 * @return the split locations
+	 * @since 2.4.7
+	 */
+	public ConfigDataLocation[] split(String delimiter) {
+		String[] values = StringUtils.delimitedListToStringArray(toString(), delimiter);
+		ConfigDataLocation[] result = new ConfigDataLocation[values.length];
+		for (int i = 0; i < values.length; i++) {
+			result[i] = of(values[i]).withOrigin(getOrigin());
+		}
+		return result;
+	}
+
 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/StandardConfigDataLocationResolver.java

@@ -115,7 +115,16 @@ public boolean isResolvable(ConfigDataLocationResolverContext context, ConfigDat
 	@Override
 	public List<StandardConfigDataResource> resolve(ConfigDataLocationResolverContext context,
 			ConfigDataLocation location) throws ConfigDataNotFoundException {
-		return resolve(getReferences(context, location));
+		return resolve(getReferences(context, location.split()));
+	}
+
+	private Set<StandardConfigDataReference> getReferences(ConfigDataLocationResolverContext context,
+			ConfigDataLocation[] configDataLocations) {
+		Set<StandardConfigDataReference> references = new LinkedHashSet<>();
+		for (ConfigDataLocation configDataLocation : configDataLocations) {
+			references.addAll(getReferences(context, configDataLocation));
+		}
+		return references;
 	}
 
 	private Set<StandardConfigDataReference> getReferences(ConfigDataLocationResolverContext context,
@@ -138,15 +147,17 @@ public List<StandardConfigDataResource> resolveProfileSpecific(ConfigDataLocatio
 		if (context.getParent() != null) {
 			return null;
 		}
-		return resolve(getProfileSpecificReferences(context, location, profiles));
+		return resolve(getProfileSpecificReferences(context, location.split(), profiles));
 	}
 
 	private Set<StandardConfigDataReference> getProfileSpecificReferences(ConfigDataLocationResolverContext context,
-			ConfigDataLocation configDataLocation, Profiles profiles) {
+			ConfigDataLocation[] configDataLocations, Profiles profiles) {
 		Set<StandardConfigDataReference> references = new LinkedHashSet<>();
-		String resourceLocation = getResourceLocation(context, configDataLocation);
 		for (String profile : profiles) {
-			references.addAll(getReferences(configDataLocation, resourceLocation, profile));
+			for (ConfigDataLocation configDataLocation : configDataLocations) {
+				String resourceLocation = getResourceLocation(context, configDataLocation);
+				references.addAll(getReferences(configDataLocation, resourceLocation, profile));
+			}
 		}
 		return references;
 	}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataEnvironmentPostProcessorIntegrationTests.java

@@ -772,6 +772,21 @@ void runWhenHasProfileSpecificImportWithCustomImportDoesNotResolveProfileSpecifi
 		assertThat(environment.containsProperty("test:boot:ps")).isFalse();
 	}
 
+	@Test // gh-26593
+	void runWhenHasFilesInRootAndConfigWithProfiles() {
+		ConfigurableApplicationContext context = this.application
+				.run("--spring.config.name=file-in-root-and-config-with-profile", "--spring.profiles.active=p1,p2");
+		ConfigurableEnvironment environment = context.getEnvironment();
+		assertThat(environment.containsProperty("file-in-root-and-config-with-profile")).isTrue();
+		assertThat(environment.containsProperty("file-in-root-and-config-with-profile-p1")).isTrue();
+		assertThat(environment.containsProperty("file-in-root-and-config-with-profile-p2")).isTrue();
+		assertThat(environment.containsProperty("config-file-in-root-and-config-with-profile")).isTrue();
+		assertThat(environment.containsProperty("config-file-in-root-and-config-with-profile-p1")).isTrue();
+		assertThat(environment.containsProperty("config-file-in-root-and-config-with-profile-p2")).isTrue();
+		assertThat(environment.getProperty("v1")).isEqualTo("config-file-in-root-and-config-with-profile-p2");
+		assertThat(environment.getProperty("v2")).isEqualTo("file-in-root-and-config-with-profile-p2");
+	}
+
 	private Condition<ConfigurableEnvironment> matchingPropertySource(final String sourceName) {
 		return new Condition<ConfigurableEnvironment>("environment containing property source " + sourceName) {
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataLocationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -134,4 +134,36 @@ void ofReturnsLocation() {
 		assertThat(ConfigDataLocation.of("test")).hasToString("test");
 	}
 
+	@Test
+	void splitWhenNoSemiColonReturnsSingleElement() {
+		ConfigDataLocation location = ConfigDataLocation.of("test");
+		ConfigDataLocation[] split = location.split();
+		assertThat(split).containsExactly(ConfigDataLocation.of("test"));
+	}
+
+	@Test
+	void splitWhenSemiColonReturnsElements() {
+		ConfigDataLocation location = ConfigDataLocation.of("one;two;three");
+		ConfigDataLocation[] split = location.split();
+		assertThat(split).containsExactly(ConfigDataLocation.of("one"), ConfigDataLocation.of("two"),
+				ConfigDataLocation.of("three"));
+	}
+
+	@Test
+	void splitOnCharReturnsElements() {
+		ConfigDataLocation location = ConfigDataLocation.of("one::two::three");
+		ConfigDataLocation[] split = location.split("::");
+		assertThat(split).containsExactly(ConfigDataLocation.of("one"), ConfigDataLocation.of("two"),
+				ConfigDataLocation.of("three"));
+	}
+
+	@Test
+	void splitWhenHasOriginReturnsElementsWithOriginSet() {
+		Origin origin = mock(Origin.class);
+		ConfigDataLocation location = ConfigDataLocation.of("a;b").withOrigin(origin);
+		ConfigDataLocation[] split = location.split();
+		assertThat(split[0].getOrigin()).isEqualTo(origin);
+		assertThat(split[1].getOrigin()).isEqualTo(origin);
+	}
+
 }

spring-boot-project/spring-boot/src/test/resources/config/file-in-root-and-config-with-profile-p1.properties

@@ -0,0 +1,3 @@
+config-file-in-root-and-config-with-profile-p1=true
+v1=config-file-in-root-and-config-with-profile-p1
+#v2 intentionally missing

spring-boot-project/spring-boot/src/test/resources/config/file-in-root-and-config-with-profile-p2.properties

@@ -0,0 +1,3 @@
+config-file-in-root-and-config-with-profile-p2=true
+v1=config-file-in-root-and-config-with-profile-p2
+#v2 intentionally missing

spring-boot-project/spring-boot/src/test/resources/config/file-in-root-and-config-with-profile.properties

@@ -0,0 +1,3 @@
+config-file-in-root-and-config-with-profile=true
+v1=config-file-in-root-and-config-with-profile
+v2=config-file-in-root-and-config-with-profile

spring-boot-project/spring-boot/src/test/resources/file-in-root-and-config-with-profile-p1.properties

@@ -0,0 +1,3 @@
+file-in-root-and-config-with-profile-p1=true
+v1=file-in-root-and-config-with-profile-p1
+v2=file-in-root-and-config-with-profile-p1

spring-boot-project/spring-boot/src/test/resources/file-in-root-and-config-with-profile-p2.properties

@@ -0,0 +1,3 @@
+file-in-root-and-config-with-profile-p2=true
+v1=file-in-root-and-config-with-profile-p2
+v2=file-in-root-and-config-with-profile-p2

spring-boot-project/spring-boot/src/test/resources/file-in-root-and-config-with-profile.properties

@@ -0,0 +1,3 @@
+file-in-root-and-config-with-profile=true
+v1=file-in-root-and-config-with-profile
+v2=file-in-root-and-config-with-profile