Merge pull request #65 from quen2404/fix/issue-64-npe-request-content

Fix NPE when only description changed in request content

Author: quen2404

src/main/java/com/qdesrame/openapi/diff/output/MarkdownRender.java

@@ -104,6 +104,7 @@ protected String listEndpoints(List<ChangedOperation> changedOperations) {
               if (operation.resultRequestBody().isDifferent()) {
                 details
                     .append(titleH5("Request:"))
+                    .append(metadata("Description", operation.getRequestBody().getDescription()))
                     .append(bodyContent(operation.getRequestBody().getContent()));
               }
               if (operation.resultApiResponses().isDifferent()) {
@@ -212,6 +213,9 @@ protected String itemHeader(String title, String mediaType, String description)
   }
 
   protected String bodyContent(String prefix, ChangedContent changedContent) {
+    if (changedContent == null) {
+      return "";
+    }
     StringBuilder sb = new StringBuilder("\n");
     sb.append(listContent(prefix, "New content type", changedContent.getIncreased()));
     sb.append(listContent(prefix, "Deleted content type", changedContent.getMissing()));
@@ -499,7 +503,7 @@ protected String metadata(String beginning, String name, ChangedMetadata changed
     if (changedMetadata == null) {
       return "";
     }
-    if (isUnchanged(changedMetadata) && showChangedMetadata) {
+    if (!isUnchanged(changedMetadata) && showChangedMetadata) {
       return format(
           "Changed %s:\n%s\nto:\n%s\n\n",
           name,