List classes with no class-level conditions in the auto-config report

This commit adds a new "Unconditional classes" section to the
auto-configuration report. It lists any auto-configuration classes
that do not have any class-level conditions, i.e. the class will be
always be part of the application's configuration.

Closes gh-2209

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfigurationImportSelector.java

@@ -80,6 +80,8 @@ class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
 			excluded.addAll(Arrays.asList(attributes.getStringArray("excludeName")));
 			factories.removeAll(excluded);
 			ConditionEvaluationReport.get(this.beanFactory).recordExclusions(excluded);
+			ConditionEvaluationReport.get(this.beanFactory).recordEvaluationCandidates(
+					factories);
 
 			// Sort
 			factories = new AutoConfigurationSorter(this.resourceLoader)

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/ConditionEvaluationReport.java

@@ -19,6 +19,7 @@ package org.springframework.boot.autoconfigure.condition;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -58,6 +59,8 @@ public class ConditionEvaluationReport {
 
 	private List<String> exclusions = Collections.emptyList();
 
+	private Set<String> unconditionalClasses = new HashSet<String>();
+
 	/**
 	 * Private constructor.
 	 * @see #get(ConfigurableListableBeanFactory)
@@ -76,6 +79,7 @@ public class ConditionEvaluationReport {
 		Assert.notNull(source, "Source must not be null");
 		Assert.notNull(condition, "Condition must not be null");
 		Assert.notNull(outcome, "Outcome must not be null");
+		this.unconditionalClasses.remove(source);
 		if (!this.outcomes.containsKey(source)) {
 			this.outcomes.put(source, new ConditionAndOutcomes());
 		}
@@ -92,6 +96,16 @@ public class ConditionEvaluationReport {
 		this.exclusions = new ArrayList<String>(exclusions);
 	}
 
+	/**
+	 * Records the names of the classes that are candidates for condition evaluation
+	 * @param evaluationCandidates the names of the classes whose conditions will be
+	 * evaluated
+	 */
+	public void recordEvaluationCandidates(List<String> evaluationCandidates) {
+		Assert.notNull(evaluationCandidates, "evaluationCandidates must not be null");
+		this.unconditionalClasses = new HashSet<String>(evaluationCandidates);
+	}
+
 	/**
 	 * Returns condition outcomes from this report, grouped by the source.
 	 * @return the condition outcomes
@@ -127,6 +141,14 @@ public class ConditionEvaluationReport {
 		return Collections.unmodifiableList(this.exclusions);
 	}
 
+	/**
+	 * Returns the name of the classes that were evaluated but were not conditional.
+	 * @return the names of the unconditional classes
+	 */
+	public Set<String> getUnconditionalClasses() {
+		return Collections.unmodifiableSet(this.unconditionalClasses);
+	}
+
 	/**
 	 * The parent report (from a parent BeanFactory if there is one).
 	 * @return the parent report (or null if there isn't one)

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/logging/AutoConfigurationReportLoggingInitializer.java

@@ -151,6 +151,17 @@ public class AutoConfigurationReportLoggingInitializer implements
 			}
 		}
 		message.append("\n\n");
+		message.append("Unconditional classes:\n");
+		message.append("----------------------\n");
+		if (report.getUnconditionalClasses().isEmpty()) {
+			message.append("\n    None\n");
+		}
+		else {
+			for (String unconditionalClass : report.getUnconditionalClasses()) {
+				message.append("\n   " + unconditionalClass + "\n");
+			}
+		}
+		message.append("\n\n");
 		return message;
 	}