openolat#95: check if the precondition is null before trying to replace the...

openolat#95: check if the precondition is null before trying to replace the ids in the migration process

src/main/java/de/bps/course/nodewizard/coursenode/AbstractCourseNodeCopyConfigurator.java

@@ -24,7 +24,6 @@ import java.util.Arrays;
 import java.util.List;
 
 import org.olat.core.CoreSpringFactory;
-import org.olat.core.gui.translator.Translator;
 import org.olat.core.id.Identity;
 import org.olat.course.condition.Condition;
 import org.olat.course.condition.KeyAndNameConverter;
@@ -135,8 +134,10 @@ public class AbstractCourseNodeCopyConfigurator implements ICourseNodeCopyConfig
 			preCondition.setEasyModeNodePassedId(easyModeNodePassedId);
 		}
 		if (preCondition.isExpertMode()) {
-			preCondition.setConditionExpression(
+			if (preCondition.getConditionExpression() != null) {
+				preCondition.setConditionExpression(
 					replaceIdsInCondition(preCondition.getConditionExpression()));
+			}
 		} else {
 			preCondition.setConditionExpression(
 					preCondition.getConditionFromEasyModeConfiguration());