null pointer for empty content files mentioned in [TOC]

Author: MaxMelcher

.vscode/launch.json

@@ -14,11 +14,11 @@
                 "--verbose",
                 //"-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\DeepLink",
                 "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\AzureDevOps.WikiPDFExport.wiki",
-                //                "--attachments-path=..\\AzureDevOps.WikiPDFExport.Test\\Tests\\AzureDevOps.WikiPDFExport.wiki\\.attachments\\",
-                //               "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Code",
-                //                "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Azure-Platform-Design",
-                //                "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\1k",
-                //                "-s..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Test-Emoticon\\emoji.md",
+                //                 "--attachments-path=..\\AzureDevOps.WikiPDFExport.Test\\Tests\\AzureDevOps.WikiPDFExport.wiki\\.attachments\\",
+                //                 "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Code",
+                //                 "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Azure-Platform-Design",
+                //                 "-p..\\AzureDevOps.WikiPDFExport.Test\\Tests\\1k",
+                //                 "-s..\\AzureDevOps.WikiPDFExport.Test\\Tests\\Test-Emoticon\\emoji.md",
                 "--heading",
                 "--breakPage",
                 //              "-m",

AzureDevOps.WikiPDFExport/WikiPDFExporter.cs

@@ -407,8 +407,10 @@ private string ConvertMarkdownToHTML(List<MarkdownFile> files)
             pipelineBuilder.Extensions.RemoveAll(x => x is Markdig.Extensions.AutoIdentifiers.AutoIdentifierExtension);
             //handled by katex
             pipelineBuilder.Extensions.RemoveAll(x => x is Markdig.Extensions.Mathematics.MathExtension);
+            
+            //todo: is this needed? it will stop support of resizing images:
             //this interferes with katex parsing of {} elements.
-            pipelineBuilder.Extensions.RemoveAll(x => x is Markdig.Extensions.GenericAttributes.GenericAttributesExtension);
+            //pipelineBuilder.Extensions.RemoveAll(x => x is Markdig.Extensions.GenericAttributes.GenericAttributesExtension);
 
             DeepLinkExtension deeplink = new DeepLinkExtension();
             pipelineBuilder.Extensions.Add(deeplink);
@@ -461,6 +463,10 @@ private string ConvertMarkdownToHTML(List<MarkdownFile> files)
 
                 var md = mf.Content;
 
+                if (string.IsNullOrEmpty(md)) { 
+                    Log($"File {file.FullName} is empty and will be skipped!", LogLevel.Warning, 1);
+                    continue;}
+
                 //rename TOC tags to fit to MarkdigToc or delete them from each markdown document
                 var newTOCString = _options.GlobalTOC != null ? "" : "[TOC]"; 
                 md = md.Replace("[[_TOC_]]", newTOCString);