Support DeferredLogFactory injection

Update `ConfigDataLoader` and `ConfigDataLocationResolver` to support
`DeferredLogFactory` injection.

Closes gh-24988

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLoader.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.
@@ -23,14 +23,16 @@
 import org.springframework.boot.BootstrapContext;
 import org.springframework.boot.BootstrapRegistry;
 import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.logging.DeferredLogFactory;
 
 /**
  * Strategy class that can be used used to load {@link ConfigData} for a given
  * {@link ConfigDataResource}. Implementations should be added as a
  * {@code spring.factories} entries. The following constructor parameter types are
  * supported:
  * <ul>
- * <li>{@link Log} - if the resolver needs deferred logging</li>
+ * <li>{@link Log} or {@link DeferredLogFactory} - if the loader needs deferred
+ * logging</li>
  * <li>{@link ConfigurableBootstrapContext} - A bootstrap context that can be used to
  * store objects that may be expensive to create, or need to be shared
  * ({@link BootstrapContext} or {@link BootstrapRegistry} may also be used).</li>

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLoaders.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.
@@ -68,6 +68,7 @@ class ConfigDataLoaders {
 		Instantiator<ConfigDataLoader<?>> instantiator = new Instantiator<>(ConfigDataLoader.class,
 				(availableParameters) -> {
 					availableParameters.add(Log.class, logFactory::getLog);
+					availableParameters.add(DeferredLogFactory.class, logFactory);
 					availableParameters.add(ConfigurableBootstrapContext.class, bootstrapContext);
 					availableParameters.add(BootstrapContext.class, bootstrapContext);
 					availableParameters.add(BootstrapRegistry.class, bootstrapContext);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocationResolver.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.
@@ -25,6 +25,7 @@
 import org.springframework.boot.BootstrapRegistry;
 import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.context.properties.bind.Binder;
+import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.env.Environment;
@@ -36,7 +37,8 @@
  * {@code spring.factories} entries. The following constructor parameter types are
  * supported:
  * <ul>
- * <li>{@link Log} - if the resolver needs deferred logging</li>
+ * <li>{@link Log} or {@link DeferredLogFactory} - if the resolver needs deferred
+ * logging</li>
  * <li>{@link Binder} - if the resolver needs to obtain values from the initial
  * {@link Environment}</li>
  * <li>{@link ResourceLoader} - if the resolver needs a resource loader</li>

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

@@ -70,6 +70,7 @@ class ConfigDataLocationResolvers {
 		Instantiator<ConfigDataLocationResolver<?>> instantiator = new Instantiator<>(ConfigDataLocationResolver.class,
 				(availableParameters) -> {
 					availableParameters.add(Log.class, logFactory::getLog);
+					availableParameters.add(DeferredLogFactory.class, logFactory);
 					availableParameters.add(Binder.class, binder);
 					availableParameters.add(ResourceLoader.class, resourceLoader);
 					availableParameters.add(ConfigurableBootstrapContext.class, bootstrapContext);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataLoadersTests.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.
@@ -57,6 +57,20 @@ void createWhenLoaderHasLogParameterInjectsLog() {
 				Arrays.asList(LoggingConfigDataLoader.class.getName()));
 	}
 
+	@Test
+	void createWhenLoaderHasDeferredLogFactoryParameterInjectsDeferredLogFactory() {
+		ConfigDataLoaders loaders = new ConfigDataLoaders(this.logFactory, this.bootstrapContext,
+				Arrays.asList(DeferredLogFactoryConfigDataLoader.class.getName()));
+		assertThat(loaders).extracting("loaders").asList()
+				.satisfies(this::containsValidDeferredLogFactoryConfigDataLoader);
+	}
+
+	private void containsValidDeferredLogFactoryConfigDataLoader(List<?> list) {
+		assertThat(list).hasSize(1);
+		DeferredLogFactoryConfigDataLoader loader = (DeferredLogFactoryConfigDataLoader) list.get(0);
+		assertThat(loader.getLogFactory()).isSameAs(this.logFactory);
+	}
+
 	@Test
 	void createWhenLoaderHasBootstrapParametersInjectsBootstrapContext() {
 		new ConfigDataLoaders(this.logFactory, this.bootstrapContext,
@@ -144,6 +158,26 @@ public ConfigData load(ConfigDataLoaderContext context, ConfigDataResource resou
 
 	}
 
+	static class DeferredLogFactoryConfigDataLoader implements ConfigDataLoader<ConfigDataResource> {
+
+		private final DeferredLogFactory logFactory;
+
+		DeferredLogFactoryConfigDataLoader(DeferredLogFactory logFactory) {
+			assertThat(logFactory).isNotNull();
+			this.logFactory = logFactory;
+		}
+
+		@Override
+		public ConfigData load(ConfigDataLoaderContext context, ConfigDataResource resource) throws IOException {
+			throw new AssertionError("Unexpected call");
+		}
+
+		DeferredLogFactory getLogFactory() {
+			return this.logFactory;
+		}
+
+	}
+
 	static class BootstrappingConfigDataLoader implements ConfigDataLoader<ConfigDataResource> {
 
 		BootstrappingConfigDataLoader(ConfigurableBootstrapContext configurableBootstrapContext,

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataLocationResolversTests.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.
@@ -23,6 +23,7 @@
 import java.util.List;
 import java.util.function.Supplier;
 
+import org.apache.commons.logging.Log;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
@@ -68,6 +69,17 @@ class ConfigDataLocationResolversTests {
 
 	private ResourceLoader resourceLoader = new DefaultResourceLoader();
 
+	@Test
+	void createWhenInjectingLogAndDeferredLogFactoryCreatesResolver() {
+		ConfigDataLocationResolvers resolvers = new ConfigDataLocationResolvers(this.logFactory, this.bootstrapContext,
+				this.binder, this.resourceLoader, Collections.singletonList(TestLogResolver.class.getName()));
+		assertThat(resolvers.getResolvers()).hasSize(1);
+		assertThat(resolvers.getResolvers().get(0)).isExactlyInstanceOf(TestLogResolver.class);
+		TestLogResolver resolver = (TestLogResolver) resolvers.getResolvers().get(0);
+		assertThat(resolver.getDeferredLogFactory()).isSameAs(this.logFactory);
+		assertThat(resolver.getLog()).isNotNull();
+	}
+
 	@Test
 	void createWhenInjectingBinderCreatesResolver() {
 		ConfigDataLocationResolvers resolvers = new ConfigDataLocationResolvers(this.logFactory, this.bootstrapContext,
@@ -180,6 +192,27 @@ public List<TestConfigDataResource> resolveProfileSpecific(ConfigDataLocationRes
 
 	}
 
+	static class TestLogResolver extends TestResolver {
+
+		private final DeferredLogFactory deferredLogFactory;
+
+		private final Log log;
+
+		TestLogResolver(DeferredLogFactory deferredLogFactory, Log log) {
+			this.deferredLogFactory = deferredLogFactory;
+			this.log = log;
+		}
+
+		DeferredLogFactory getDeferredLogFactory() {
+			return this.deferredLogFactory;
+		}
+
+		Log getLog() {
+			return this.log;
+		}
+
+	}
+
 	static class TestBoundResolver extends TestResolver {
 
 		private final Binder binder;