Handle file with name matching an optional wildcard location

Previously, the presence of a file with the same name
as an optional wildcard location would cause a failure. With
this change the pattern is resolved only if the resource is a
directory.

Additionally, if an optional wildcard search location that was a file
would also fail with an exception. This commit fixes that so that those
locations are not resolved.

Fixes gh-27120
Fixes gh-27209

Author: mbhave

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

@@ -95,12 +95,15 @@ Resource[] getResources(String location, ResourceType type) {
 		validatePattern(location, type);
 		String directoryPath = location.substring(0, location.indexOf("*/"));
 		String fileName = location.substring(location.lastIndexOf("/") + 1);
-		Resource directoryResource = getResource(directoryPath);
-		if (!directoryResource.exists()) {
-			return new Resource[] { directoryResource };
+		Resource resource = getResource(directoryPath);
+		if (!resource.exists()) {
+			return EMPTY_RESOURCES;
+		}
+		File file = getFile(location, resource);
+		if (!file.isDirectory()) {
+			return EMPTY_RESOURCES;
 		}
-		File directory = getDirectory(location, directoryResource);
-		File[] subDirectories = directory.listFiles(this::isVisibleDirectory);
+		File[] subDirectories = file.listFiles(this::isVisibleDirectory);
 		if (subDirectories == null) {
 			return EMPTY_RESOURCES;
 		}
@@ -131,11 +134,9 @@ private void validatePattern(String location, ResourceType type) {
 		Assert.state(directoryPath.endsWith("*/"), () -> String.format("Location '%s' must end with '*/'", location));
 	}
 
-	private File getDirectory(String patternLocation, Resource resource) {
+	private File getFile(String patternLocation, Resource resource) {
 		try {
-			File directory = resource.getFile();
-			Assert.state(directory.isDirectory(), () -> "'" + directory + "' is not a directory");
-			return directory;
+			return resource.getFile();
 		}
 		catch (Exception ex) {
 			throw new IllegalStateException(

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

@@ -257,7 +257,9 @@ private Collection<StandardConfigDataResource> resolveEmptyDirectories(
 			Set<StandardConfigDataReference> references) {
 		Set<StandardConfigDataResource> empty = new LinkedHashSet<>();
 		for (StandardConfigDataReference reference : references) {
-			empty.addAll(resolveEmptyDirectories(reference));
+			if (reference.getDirectory() != null) {
+				empty.addAll(resolveEmptyDirectories(reference));
+			}
 		}
 		return empty;
 	}

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

@@ -709,6 +709,18 @@ void runWhenHasWildcardLocationLoadsFromAllMatchingLocations() {
 		assertThat(environment.getProperty("second.property")).isEqualTo("ball");
 	}
 
+	@Test
+	void runWhenOptionalWildcardLocationDoesNotExistDoesNotThrowException() {
+		assertThatNoException().isThrownBy(() -> this.application.run(
+				"--spring.config.location=optional:file:src/test/resources/nonexistent/*/testproperties.properties"));
+	}
+
+	@Test
+	void runWhenMandatoryWildcardLocationDoesNotExistThrowsException() {
+		assertThatExceptionOfType(ConfigDataLocationNotFoundException.class).isThrownBy(() -> this.application
+				.run("--spring.config.location=file:src/test/resources/nonexistent/*/testproperties.properties"));
+	}
+
 	@Test
 	void runWhenMandatoryWildcardLocationHasEmptyFileDirectory() {
 		assertThatNoException()

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

@@ -34,6 +34,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatNoException;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 
@@ -151,6 +152,12 @@ void resolveWhenLocationIsWildcardDirectoriesSortsAlphabeticallyBasedOnAbsoluteP
 				filePath("src", "test", "resources", "config", "2-second", "testproperties.properties"));
 	}
 
+	@Test
+	void resolveWhenLocationIsWildcardAndMatchingFilePresentShouldNotFail() {
+		ConfigDataLocation location = ConfigDataLocation.of("optional:file:src/test/resources/a-file/*/");
+		assertThatNoException().isThrownBy(() -> this.resolver.resolve(this.context, location));
+	}
+
 	@Test
 	void resolveWhenLocationIsWildcardFilesLoadsAllFilesThatMatch() {
 		ConfigDataLocation location = ConfigDataLocation