Refactor TOC processing to handle excluded and unreachable files (#278)

* Refactor TOC processing to handle excluded and unreachable files

Updated the TOC processing logic to emit errors for excluded or unreachable files and ensure valid navigation indexes. These changes improve diagnostics during documentation builds and prevent invalid entries in the output structure.

* revert changes to assembly conf, unrelated to this PR

src/Elastic.Markdown/IO/DocumentationSet.cs

@@ -64,12 +64,18 @@ public DocumentationSet(BuildContext context)
 			.ToDictionary(g => g.Key, g => g.ToArray());
 
 		var fileIndex = 0;
-		Tree = new DocumentationGroup(Configuration.TableOfContents, FlatMappedFiles, folderFiles, ref fileIndex)
+		Tree = new DocumentationGroup(Context, Configuration.TableOfContents, FlatMappedFiles, folderFiles, ref fileIndex)
 		{
 			Parent = null
 		};
 
-		MarkdownFiles = Files.OfType<MarkdownFile>().ToDictionary(i => i.NavigationIndex, i => i).ToFrozenDictionary();
+		var markdownFiles = Files.OfType<MarkdownFile>().ToArray();
+
+		var excludedChildren = markdownFiles.Where(f => f.NavigationIndex == -1).ToArray();
+		foreach (var excludedChild in excludedChildren)
+			Context.EmitError(Context.ConfigurationPath, $"{excludedChild.RelativePath} is unreachable in the TOC because one of its parents matches exclusion glob");
+
+		MarkdownFiles = markdownFiles.Where(f => f.NavigationIndex > -1).ToDictionary(i => i.NavigationIndex, i => i).ToFrozenDictionary();
 
 	}
 

src/Elastic.Markdown/IO/MarkdownFile.cs

@@ -61,7 +61,7 @@ public string? NavigationTitle
 	public string FileName { get; }
 	public string Url => $"{UrlPathPrefix}/{RelativePath.Replace(".md", ".html")}";
 
-	public int NavigationIndex { get; set; }
+	public int NavigationIndex { get; internal set; } = -1;
 
 	private bool _instructionsParsed;
 	private DocumentationGroup? _parent;

src/Elastic.Markdown/IO/Navigation/DocumentationGroup.cs

@@ -2,6 +2,7 @@
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
 
+using Elastic.Markdown.Diagnostics;
 using Elastic.Markdown.IO.Configuration;
 
 namespace Elastic.Markdown.IO.Navigation;
@@ -33,16 +34,16 @@ public class DocumentationGroup
 	public int Depth { get; }
 
 	public DocumentationGroup(
+		BuildContext context,
 		IReadOnlyCollection<ITocItem> toc,
 		IDictionary<string, DocumentationFile> lookup,
 		IDictionary<string, DocumentationFile[]> folderLookup,
 		ref int fileIndex,
 		int depth = 0,
-		MarkdownFile? index = null
-	)
+		MarkdownFile? index = null)
 	{
 		Depth = depth;
-		Index = ProcessTocItems(index, toc, lookup, folderLookup, depth, ref fileIndex, out var groups, out var files, out var navigationItems);
+		Index = ProcessTocItems(context, index, toc, lookup, folderLookup, depth, ref fileIndex, out var groups, out var files, out var navigationItems);
 
 		GroupsInOrder = groups;
 		FilesInOrder = files;
@@ -55,6 +56,7 @@ public DocumentationGroup(
 	}
 
 	private MarkdownFile? ProcessTocItems(
+		BuildContext context,
 		MarkdownFile? configuredIndex,
 		IReadOnlyCollection<ITocItem> toc,
 		IDictionary<string, DocumentationFile> lookup,
@@ -73,15 +75,26 @@ public DocumentationGroup(
 		{
 			if (tocItem is FileReference file)
 			{
-				if (!lookup.TryGetValue(file.Path, out var d) || d is not MarkdownFile md)
+				if (!lookup.TryGetValue(file.Path, out var d))
+				{
+					context.EmitError(context.ConfigurationPath, $"The following file could not be located: {file.Path} it may be excluded from the build in docset.yml");
+					continue;
+				}
+				if (d is ExcludedFile excluded && excluded.RelativePath.EndsWith(".md"))
+				{
+					context.EmitError(context.ConfigurationPath, $"{excluded.RelativePath} matches exclusion glob from docset.yml yet appears in TOC");
+					continue;
+				}
+				if (d is not MarkdownFile md)
 					continue;
 
 				md.Parent = this;
-				md.NavigationIndex = ++fileIndex;
+				var navigationIndex = Interlocked.Increment(ref fileIndex);
+				md.NavigationIndex = navigationIndex;
 
 				if (file.Children.Count > 0 && d is MarkdownFile virtualIndex)
 				{
-					var group = new DocumentationGroup(file.Children, lookup, folderLookup, ref fileIndex, depth + 1, virtualIndex)
+					var group = new DocumentationGroup(context, file.Children, lookup, folderLookup, ref fileIndex, depth + 1, virtualIndex)
 					{
 						Parent = this
 					};
@@ -111,7 +124,7 @@ public DocumentationGroup(
 						.ToArray();
 				}
 
-				var group = new DocumentationGroup(children, lookup, folderLookup, ref fileIndex, depth + 1)
+				var group = new DocumentationGroup(context, children, lookup, folderLookup, ref fileIndex, depth + 1)
 				{
 					Parent = this
 				};