Allow auto-configure sort with incomplete chain

Update `AutoConfigurationSorter` so that all `@AutoConfigureBefore` and
`@AutoConfigureAfter` classes are considered even if they are ultimately
not part of the requested set.

Prior to this commit, given classes ordered with annotations such that
A -> B -> C a call to sort only [A, B] could return the incorrect order.

Fixes gh-12660

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationSorter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -52,7 +52,7 @@ class AutoConfigurationSorter {
 	}
 
 	public List<String> getInPriorityOrder(Collection<String> classNames) {
-		final AutoConfigurationClasses classes = new AutoConfigurationClasses(
+		AutoConfigurationClasses classes = new AutoConfigurationClasses(
 				this.metadataReaderFactory, this.autoConfigurationMetadata, classNames);
 		List<String> orderedClassNames = new ArrayList<>(classNames);
 		// Initially sort alphabetically
@@ -71,11 +71,13 @@ class AutoConfigurationSorter {
 	private List<String> sortByAnnotation(AutoConfigurationClasses classes,
 			List<String> classNames) {
 		List<String> toSort = new ArrayList<>(classNames);
+		toSort.addAll(classes.getAllNames());
 		Set<String> sorted = new LinkedHashSet<>();
 		Set<String> processing = new LinkedHashSet<>();
 		while (!toSort.isEmpty()) {
 			doSortByAfterAnnotation(classes, toSort, sorted, processing, null);
 		}
+		sorted.retainAll(classNames);
 		return new ArrayList<>(sorted);
 	}
 
@@ -104,9 +106,32 @@ class AutoConfigurationSorter {
 		AutoConfigurationClasses(MetadataReaderFactory metadataReaderFactory,
 				AutoConfigurationMetadata autoConfigurationMetadata,
 				Collection<String> classNames) {
+			addToClasses(metadataReaderFactory, autoConfigurationMetadata, classNames,
+					true);
+		}
+
+		public Set<String> getAllNames() {
+			return this.classes.keySet();
+		}
+
+		private void addToClasses(MetadataReaderFactory metadataReaderFactory,
+				AutoConfigurationMetadata autoConfigurationMetadata,
+				Collection<String> classNames, boolean required) {
 			for (String className : classNames) {
-				this.classes.put(className, new AutoConfigurationClass(className,
-						metadataReaderFactory, autoConfigurationMetadata));
+				if (!this.classes.containsKey(className)) {
+					AutoConfigurationClass autoConfigurationClass = new AutoConfigurationClass(
+							className, metadataReaderFactory, autoConfigurationMetadata);
+					boolean available = autoConfigurationClass.isAvailable();
+					if (required || available) {
+						this.classes.put(className, autoConfigurationClass);
+					}
+					if (available) {
+						addToClasses(metadataReaderFactory, autoConfigurationMetadata,
+								autoConfigurationClass.getBefore(), false);
+						addToClasses(metadataReaderFactory, autoConfigurationMetadata,
+								autoConfigurationClass.getAfter(), false);
+					}
+				}
 			}
 		}
 
@@ -136,11 +161,11 @@ class AutoConfigurationSorter {
 
 		private final AutoConfigurationMetadata autoConfigurationMetadata;
 
-		private AnnotationMetadata annotationMetadata;
+		private volatile AnnotationMetadata annotationMetadata;
 
-		private final Set<String> before;
+		private volatile Set<String> before;
 
-		private final Set<String> after;
+		private volatile Set<String> after;
 
 		AutoConfigurationClass(String className,
 				MetadataReaderFactory metadataReaderFactory,
@@ -148,15 +173,37 @@ class AutoConfigurationSorter {
 			this.className = className;
 			this.metadataReaderFactory = metadataReaderFactory;
 			this.autoConfigurationMetadata = autoConfigurationMetadata;
-			this.before = readBefore();
-			this.after = readAfter();
+		}
+
+		public boolean isAvailable() {
+			try {
+				if (!wasProcessed()) {
+					getAnnotationMetadata();
+				}
+				return true;
+			}
+			catch (Exception ex) {
+				return false;
+			}
 		}
 
 		public Set<String> getBefore() {
+			if (this.before == null) {
+				this.before = (wasProcessed()
+						? this.autoConfigurationMetadata.getSet(this.className,
+								"AutoConfigureBefore", Collections.emptySet())
+						: getAnnotationValue(AutoConfigureBefore.class));
+			}
 			return this.before;
 		}
 
 		public Set<String> getAfter() {
+			if (this.after == null) {
+				this.after = (wasProcessed()
+						? this.autoConfigurationMetadata.getSet(this.className,
+								"AutoConfigureAfter", Collections.emptySet())
+						: getAnnotationValue(AutoConfigureAfter.class));
+			}
 			return this.after;
 		}
 
@@ -171,22 +218,6 @@ class AutoConfigurationSorter {
 					: (Integer) attributes.get("value"));
 		}
 
-		private Set<String> readBefore() {
-			if (wasProcessed()) {
-				return this.autoConfigurationMetadata.getSet(this.className,
-						"AutoConfigureBefore", Collections.emptySet());
-			}
-			return getAnnotationValue(AutoConfigureBefore.class);
-		}
-
-		private Set<String> readAfter() {
-			if (wasProcessed()) {
-				return this.autoConfigurationMetadata.getSet(this.className,
-						"AutoConfigureAfter", Collections.emptySet());
-			}
-			return getAnnotationValue(AutoConfigureAfter.class);
-		}
-
 		private boolean wasProcessed() {
 			return (this.autoConfigurationMetadata != null
 					&& this.autoConfigurationMetadata.wasProcessed(this.className));

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationSorterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.autoconfigure;
 
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -29,6 +30,7 @@ import org.junit.rules.ExpectedException;
 
 import org.springframework.core.Ordered;
 import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
+import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -82,7 +84,7 @@ public class AutoConfigurationSorterTests {
 
 	@Before
 	public void setup() {
-		this.sorter = new AutoConfigurationSorter(new CachingMetadataReaderFactory(),
+		this.sorter = new AutoConfigurationSorter(new SkipCycleMetadataReaderFactory(),
 				this.autoConfigurationMetadata);
 	}
 
@@ -140,6 +142,8 @@ public class AutoConfigurationSorterTests {
 
 	@Test
 	public void byAutoConfigureAfterWithCycle() {
+		this.sorter = new AutoConfigurationSorter(new CachingMetadataReaderFactory(),
+				this.autoConfigurationMetadata);
 		this.thrown.expect(IllegalStateException.class);
 		this.thrown.expectMessage("AutoConfigure cycle detected");
 		this.sorter.getInPriorityOrder(Arrays.asList(A, B, C, D));
@@ -147,7 +151,7 @@ public class AutoConfigurationSorterTests {
 
 	@Test
 	public void usesAnnotationPropertiesWhenPossible() throws Exception {
-		MetadataReaderFactory readerFactory = mock(MetadataReaderFactory.class);
+		MetadataReaderFactory readerFactory = new SkipCycleMetadataReaderFactory();
 		this.autoConfigurationMetadata = getAutoConfigurationMetadata(A2, B, C, W2, X);
 		this.sorter = new AutoConfigurationSorter(readerFactory,
 				this.autoConfigurationMetadata);
@@ -156,6 +160,27 @@ public class AutoConfigurationSorterTests {
 		assertThat(actual).containsExactly(C, W2, B, A2, X);
 	}
 
+	@Test
+	public void useAnnotationWithNoDirectLink() throws Exception {
+		MetadataReaderFactory readerFactory = new SkipCycleMetadataReaderFactory();
+		this.autoConfigurationMetadata = getAutoConfigurationMetadata(A, B, E);
+		this.sorter = new AutoConfigurationSorter(readerFactory,
+				this.autoConfigurationMetadata);
+		List<String> actual = this.sorter.getInPriorityOrder(Arrays.asList(A, E));
+		assertThat(actual).containsExactly(E, A);
+	}
+
+	@Test
+	public void useAnnotationWithNoDirectLinkAndCycle() throws Exception {
+		MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory();
+		this.autoConfigurationMetadata = getAutoConfigurationMetadata(A, B, D);
+		this.sorter = new AutoConfigurationSorter(readerFactory,
+				this.autoConfigurationMetadata);
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("AutoConfigure cycle detected");
+		this.sorter.getInPriorityOrder(Arrays.asList(D, B));
+	}
+
 	private AutoConfigurationMetadata getAutoConfigurationMetadata(String... classNames)
 			throws Exception {
 		Properties properties = new Properties();
@@ -263,4 +288,17 @@ public class AutoConfigurationSorterTests {
 
 	}
 
+	private static class SkipCycleMetadataReaderFactory
+			extends CachingMetadataReaderFactory {
+
+		@Override
+		public MetadataReader getMetadataReader(String className) throws IOException {
+			if (className.equals(D)) {
+				throw new IOException();
+			}
+			return super.getMetadataReader(className);
+		}
+
+	}
+
 }