fix(expressions): Apparently the getMessage() of an exception can b…

…e null

… which is bad when you then generate an NPE in the finally block of some error handling code.

orca-core/src/main/java/com/netflix/spinnaker/orca/pipeline/expressions/ExpressionTransform.java

@@ -16,17 +16,19 @@
 
 package com.netflix.spinnaker.orca.pipeline.expressions;
 
-import java.util.*;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-import java.util.stream.Stream;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ExpressionParser;
 import org.springframework.expression.ParserContext;
 import org.springframework.expression.common.CompositeStringExpression;
+
+import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
 import static java.lang.String.format;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
@@ -100,7 +102,7 @@ public <T> T transform(T source, EvaluationContext evaluationContext, Expression
           Object fields = !keys.isEmpty() ? keys : literalExpression;
           String errorDescription = format("Failed to evaluate %s ", fields);
           Throwable originalException = unwrapOriginalException(exception);
-          if (originalException == null || originalException.getMessage().contains(exception.getMessage())) {
+          if (originalException == null || originalException.getMessage() == null || originalException.getMessage().contains(exception.getMessage())) {
             errorDescription += exception.getMessage();
           } else {
             errorDescription += originalException.getMessage() + " - " + exception.getMessage();