Continue failure analysis when an analyzer throws an exception

Previously, if a failure analyzer threw an exception from its
analyze method, failure analysis would stop.

This commit updates FailureAnalyzers to catch and log any Throwable
thrown by an analyzer and continue to the next available analyzer.

Closes gh-7956

Author: wilkinsona

spring-boot/src/main/java/org/springframework/boot/diagnostics/FailureAnalyzers.java

@@ -115,9 +115,14 @@ public boolean analyzeAndReport(Throwable failure) {
 
 	private FailureAnalysis analyze(Throwable failure, List<FailureAnalyzer> analyzers) {
 		for (FailureAnalyzer analyzer : analyzers) {
-			FailureAnalysis analysis = analyzer.analyze(failure);
-			if (analysis != null) {
-				return analysis;
+			try {
+				FailureAnalysis analysis = analyzer.analyze(failure);
+				if (analysis != null) {
+					return analysis;
+				}
+			}
+			catch (Throwable ex) {
+				log.debug("FailureAnalyzer " + analyzer + " failed", ex);
 			}
 		}
 		return null;

spring-boot/src/test/java/org/springframework/boot/diagnostics/FailureAnalyzersTests.java

@@ -62,9 +62,16 @@ public void beanFactoryIsInjectedIntoBeanFactoryAwareFailureAnalyzers() {
 	}
 
 	@Test
-	public void brokenAnalyzerDoesNotPreventOtherAnalyzersFromBeingCalled() {
+	public void analyzerThatFailsDuringInitializationDoesNotPreventOtherAnalyzersFromBeingCalled() {
 		RuntimeException failure = new RuntimeException();
-		analyzeAndReport("broken.factories", failure);
+		analyzeAndReport("broken-initialization.factories", failure);
+		verify(failureAnalyzer, times(1)).analyze(failure);
+	}
+
+	@Test
+	public void analyzerThatFailsDuringAnalysisDoesNotPreventOtherAnalyzersFromBeingCalled() {
+		RuntimeException failure = new RuntimeException();
+		analyzeAndReport("broken-analysis.factories", failure);
 		verify(failureAnalyzer, times(1)).analyze(failure);
 	}
 
@@ -83,7 +90,7 @@ public FailureAnalysis analyze(Throwable failure) {
 
 	}
 
-	static class BrokenFailureAnalyzer implements FailureAnalyzer {
+	static class BrokenInitializationFailureAnalyzer implements FailureAnalyzer {
 
 		static {
 			Object foo = null;
@@ -97,6 +104,15 @@ public FailureAnalysis analyze(Throwable failure) {
 
 	}
 
+	static class BrokenAnalysisFailureAnalyzer implements FailureAnalyzer {
+
+		@Override
+		public FailureAnalysis analyze(Throwable failure) {
+			throw new NoClassDefFoundError();
+		}
+
+	}
+
 	interface BeanFactoryAwareFailureAnalyzer extends BeanFactoryAware, FailureAnalyzer {
 
 	}

spring-boot/src/test/resources/failure-analyzers-tests/broken.factories renamed to spring-boot/src/test/resources/failure-analyzers-tests/broken-analysis.factories

@@ -1,4 +1,4 @@
 # Failure Analyzers
 org.springframework.boot.diagnostics.FailureAnalyzer=\
-org.springframework.boot.diagnostics.FailureAnalyzersTests$BrokenFailureAnalyzer,\
+org.springframework.boot.diagnostics.FailureAnalyzersTests$BrokenAnalysisFailureAnalyzer,\
 org.springframework.boot.diagnostics.FailureAnalyzersTests$BasicFailureAnalyzer

spring-boot/src/test/resources/failure-analyzers-tests/broken-initialization.factories

@@ -0,0 +1,4 @@
+# Failure Analyzers
+org.springframework.boot.diagnostics.FailureAnalyzer=\
+org.springframework.boot.diagnostics.FailureAnalyzersTests$BrokenAnalysisFailureAnalyzer,\
+org.springframework.boot.diagnostics.FailureAnalyzersTests$BasicFailureAnalyzer