Disable incrementalBuildTypeRenamed test

This commit disables a test that does not test what it is supposed to
and improve the Metadata assertions to fail early if more than one
matching item by name and type is found in the metadata.

See gh-26271

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/IncrementalBuildMetadataGenerationTests.java

 /*
- * 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.boot.configurationprocessor;
 
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
@@ -74,6 +75,7 @@ class IncrementalBuildMetadataGenerationTests extends AbstractMetadataGeneration
 	}
 
 	@Test
+	@Disabled("gh-26271")
 	void incrementalBuildTypeRenamed() throws Exception {
 		TestProject project = new TestProject(this.tempDir, FooProperties.class, BarProperties.class);
 		ConfigurationMetadata metadata = project.fullBuild();

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/metadata/Metadata.java

 /*
- * Copyright 2012-2019 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.
@@ -20,6 +20,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.assertj.core.api.Condition;
 import org.hamcrest.collection.IsMapContaining;
@@ -131,7 +132,7 @@ public final class Metadata {
 
 		@Override
 		public boolean matches(ConfigurationMetadata value) {
-			ItemMetadata itemMetadata = getFirstItemWithName(value, this.name);
+			ItemMetadata itemMetadata = findItem(value, this.name);
 			if (itemMetadata == null) {
 				return false;
 			}
@@ -207,13 +208,14 @@ public final class Metadata {
 					this.description, this.defaultValue, null);
 		}
 
-		private ItemMetadata getFirstItemWithName(ConfigurationMetadata metadata, String name) {
-			for (ItemMetadata item : metadata.getItems()) {
-				if (item.isOfItemType(this.itemType) && name.equals(item.getName())) {
-					return item;
-				}
+		private ItemMetadata findItem(ConfigurationMetadata metadata, String name) {
+			List<ItemMetadata> candidates = metadata.getItems().stream()
+					.filter((item) -> item.isOfItemType(this.itemType) && name.equals(item.getName()))
+					.collect(Collectors.toList());
+			if (candidates.size() > 1) {
+				throw new IllegalStateException("More that one metadata item with name '" + name + "': " + candidates);
 			}
-			return null;
+			return (candidates.size() == 1) ? candidates.get(0) : null;
 		}
 
 	}