Limit when SystemEnvironment mapping is used

Update `SpringConfigurationPropertySource` so that the
`SystemEnvironmentPropertyMapper` is only used for the "actual" system
environment property source. This allows SystemEnvironmentProperySource
class to be used for other purposes (for example, Spring Cloud uses it
to as an override source providing decryption).

Only property sources named `systemEnvironment` or ending with
`-systemEnvironment` now have the `SystemEnvironmentPropertyMapper`
applied. The `TestPropertyValues` has been retrofitted to name the
source it adds appropriately.

Fixes gh-10840

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/info/EnvironmentInfoContributorTests.java

@@ -57,7 +57,7 @@ public class EnvironmentInfoContributorTests {
 	@SuppressWarnings("unchecked")
 	public void propertiesFromEnvironmentShouldBindCorrectly() throws Exception {
 		TestPropertyValues.of("INFO_ENVIRONMENT_FOO=green").applyTo(this.environment,
-				Type.SYSTEM);
+				Type.SYSTEM_ENVIRONMENT);
 		Info actual = contributeFrom(this.environment);
 		assertThat(actual.get("environment", Map.class)).containsEntry("foo", "green");
 	}

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/util/TestPropertyValues.java

@@ -34,6 +34,7 @@ import org.springframework.core.env.Environment;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
+import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.env.SystemEnvironmentPropertySource;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -98,7 +99,7 @@ public final class TestPropertyValues {
 	 * @param type the type of {@link PropertySource} to be added. See {@link Type}
 	 */
 	public void applyTo(ConfigurableEnvironment environment, Type type) {
-		applyTo(environment, type, "test");
+		applyTo(environment, type, type.applySuffix("test"));
 	}
 
 	/**
@@ -212,23 +213,31 @@ public final class TestPropertyValues {
 		/**
 		 * Used for {@link SystemEnvironmentPropertySource}.
 		 */
-		SYSTEM(SystemEnvironmentPropertySource.class),
+		SYSTEM_ENVIRONMENT(SystemEnvironmentPropertySource.class,
+				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME),
 
 		/**
 		 * Used for {@link MapPropertySource}.
 		 */
-		MAP(MapPropertySource.class);
+		MAP(MapPropertySource.class, null);
 
-		private Class<? extends MapPropertySource> sourceClass;
+		private final Class<? extends MapPropertySource> sourceClass;
 
-		Type(Class<? extends MapPropertySource> sourceClass) {
+		private final String suffix;
+
+		Type(Class<? extends MapPropertySource> sourceClass, String suffix) {
 			this.sourceClass = sourceClass;
+			this.suffix = (suffix == null ? null : "-" + suffix);
 		}
 
 		public Class<? extends MapPropertySource> getSourceClass() {
 			return this.sourceClass;
 		}
 
+		protected String applySuffix(String name) {
+			return (this.suffix == null ? name : name + "-" + this.suffix);
+		}
+
 	}
 
 	/**

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/util/TestPropertyValuesTests.java

@@ -54,8 +54,10 @@ public class TestPropertyValuesTests {
 
 	@Test
 	public void applyToSystemPropertySource() throws Exception {
-		TestPropertyValues.of("FOO_BAR=BAZ").applyTo(this.environment, Type.SYSTEM);
+		TestPropertyValues.of("FOO_BAR=BAZ").applyTo(this.environment, Type.SYSTEM_ENVIRONMENT);
 		assertThat(this.environment.getProperty("foo.bar")).isEqualTo("BAZ");
+		assertThat(this.environment.getPropertySources().contains(
+				"test-" + StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME));
 	}
 
 	@Test
@@ -70,7 +72,7 @@ public class TestPropertyValuesTests {
 			throws Exception {
 		TestPropertyValues.of("foo.bar=baz", "hello.world=hi").applyTo(this.environment,
 				Type.MAP, "other");
-		TestPropertyValues.of("FOO_BAR=BAZ").applyTo(this.environment, Type.SYSTEM,
+		TestPropertyValues.of("FOO_BAR=BAZ").applyTo(this.environment, Type.SYSTEM_ENVIRONMENT,
 				"other");
 		assertThat(this.environment.getPropertySources().get("other"))
 				.isInstanceOf(SystemEnvironmentPropertySource.class);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringConfigurationPropertySource.java

@@ -27,6 +27,7 @@ import org.springframework.boot.origin.Origin;
 import org.springframework.boot.origin.PropertySourceOrigin;
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.PropertySource;
+import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.env.SystemEnvironmentPropertySource;
 import org.springframework.util.Assert;
 
@@ -150,12 +151,20 @@ class SpringConfigurationPropertySource implements ConfigurationPropertySource {
 	}
 
 	private static PropertyMapper getPropertyMapper(PropertySource<?> source) {
-		if (source instanceof SystemEnvironmentPropertySource) {
+		if (source instanceof SystemEnvironmentPropertySource
+				&& hasSystemEnvironmentName(source)) {
 			return SystemEnvironmentPropertyMapper.INSTANCE;
 		}
 		return DefaultPropertyMapper.INSTANCE;
 	}
 
+	private static boolean hasSystemEnvironmentName(PropertySource<?> source) {
+		String name = source.getName();
+		return StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME.equals(name)
+				|| name.endsWith("-"
+						+ StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME);
+	}
+
 	private static boolean isFullEnumerable(PropertySource<?> source) {
 		PropertySource<?> rootSource = getRootSource(source);
 		if (rootSource.getSource() instanceof Map) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBinderTests.java

@@ -27,6 +27,7 @@ import org.springframework.boot.context.properties.bind.validation.BindValidatio
 import org.springframework.boot.context.properties.bind.validation.ValidationErrors;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.env.SystemEnvironmentPropertySource;
 import org.springframework.mock.env.MockEnvironment;
 import org.springframework.test.context.support.TestPropertySourceUtils;
@@ -192,7 +193,8 @@ public class ConfigurationPropertiesBinderTests {
 	@Test
 	public void bindToMapWithSystemProperties() {
 		MutablePropertySources propertySources = new MutablePropertySources();
-		propertySources.addLast(new SystemEnvironmentPropertySource("system",
+		propertySources.addLast(new SystemEnvironmentPropertySource(
+				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
 				Collections.singletonMap("TEST_MAP_FOO_BAR", "baz")));
 		ConfigurationPropertiesBinder binder = new ConfigurationPropertiesBinder(
 				propertySources, null, null);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/BackCompatibiltyBinderIntegrationTests.java

@@ -34,11 +34,10 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 public class BackCompatibiltyBinderIntegrationTests {
 
-	// gh-10873
-
 	@Test
 	public void bindWhenBindingCamelCaseToEnvironmentWithExtractUnderscore()
 			throws Exception {
+		// gh-10873
 		MockEnvironment environment = new MockEnvironment();
 		SystemEnvironmentPropertySource propertySource = new SystemEnvironmentPropertySource(
 				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
@@ -49,6 +48,17 @@ public class BackCompatibiltyBinderIntegrationTests {
 		assertThat(result.getZkNodes()).isEqualTo("foo");
 	}
 
+	@Test
+	public void bindWhenUsingSystemEnvronmentToOverride() {
+		MockEnvironment environment = new MockEnvironment();
+		SystemEnvironmentPropertySource propertySource = new SystemEnvironmentPropertySource(
+				"override", Collections.singletonMap("foo.password", "test"));
+		environment.getPropertySources().addFirst(propertySource);
+		PasswordProperties result = Binder.get(environment)
+				.bind("foo", Bindable.of(PasswordProperties.class)).get();
+		assertThat(result.getPassword()).isEqualTo("test");
+	}
+
 	public static class ExampleCamelCaseBean {
 
 		private String zkNodes;
@@ -63,4 +73,17 @@ public class BackCompatibiltyBinderIntegrationTests {
 
 	}
 
+	protected static class PasswordProperties {
+
+		private String password;
+
+		public String getPassword() {
+			return this.password;
+		}
+
+		public void setPassword(String password) {
+			this.password = password;
+		}
+
+	}
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringConfigurationPropertySourcesTests.java

@@ -66,7 +66,22 @@ public class SpringConfigurationPropertySourcesTests {
 	@Test
 	public void shouldAdaptSystemEnvironmentPropertySource() throws Exception {
 		MutablePropertySources sources = new MutablePropertySources();
-		sources.addLast(new SystemEnvironmentPropertySource("system",
+		sources.addLast(new SystemEnvironmentPropertySource(
+				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
+				Collections.singletonMap("SERVER_PORT", "1234")));
+		Iterator<ConfigurationPropertySource> iterator = new SpringConfigurationPropertySources(
+				sources).iterator();
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("server.port");
+		assertThat(iterator.next().getConfigurationProperty(name).getValue())
+				.isEqualTo("1234");
+		assertThat(iterator.hasNext()).isFalse();
+	}
+
+	@Test
+	public void shouldExtendedAdaptSystemEnvironmentPropertySource() throws Exception {
+		MutablePropertySources sources = new MutablePropertySources();
+		sources.addLast(new SystemEnvironmentPropertySource(
+				"test-" + StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
 				Collections.singletonMap("SERVER_PORT", "1234")));
 		Iterator<ConfigurationPropertySource> iterator = new SpringConfigurationPropertySources(
 				sources).iterator();
@@ -76,6 +91,19 @@ public class SpringConfigurationPropertySourcesTests {
 		assertThat(iterator.hasNext()).isFalse();
 	}
 
+	@Test
+	public void shouldNotAdaptSystemEnvironmentPropertyOverrideSource() throws Exception {
+		MutablePropertySources sources = new MutablePropertySources();
+		sources.addLast(new SystemEnvironmentPropertySource("override",
+				Collections.singletonMap("server.port", "1234")));
+		Iterator<ConfigurationPropertySource> iterator = new SpringConfigurationPropertySources(
+				sources).iterator();
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("server.port");
+		assertThat(iterator.next().getConfigurationProperty(name).getValue())
+				.isEqualTo("1234");
+		assertThat(iterator.hasNext()).isFalse();
+	}
+
 	@Test
 	public void shouldAdaptMultiplePropertySources() throws Exception {
 		MutablePropertySources sources = new MutablePropertySources();