Implement crosslink empty text auto-title feature

Co-authored-by: reakaleek <[email protected]>

Author: Copilot

src/Elastic.Documentation.Links/CrossLinks/CrossLinkResolver.cs

@@ -10,6 +10,7 @@ namespace Elastic.Documentation.Links.CrossLinks;
 public interface ICrossLinkResolver
 {
 	bool TryResolve(Action<string> errorEmitter, Uri crossLinkUri, [NotNullWhen(true)] out Uri? resolvedUri);
+	bool TryGetLinkMetadata(Uri crossLinkUri, [NotNullWhen(true)] out LinkMetadata? linkMetadata);
 	IUriEnvironmentResolver UriResolver { get; }
 }
 
@@ -24,6 +25,13 @@ public bool TryResolve(Action<string> errorEmitter, Uri crossLinkUri, [NotNullWh
 		return false;
 	}
 
+	/// <inheritdoc />
+	public bool TryGetLinkMetadata(Uri crossLinkUri, [NotNullWhen(true)] out LinkMetadata? linkMetadata)
+	{
+		linkMetadata = null;
+		return false;
+	}
+
 	/// <inheritdoc />
 	public IUriEnvironmentResolver UriResolver { get; } = new IsolatedBuildEnvironmentUriResolver();
 
@@ -39,6 +47,20 @@ public class CrossLinkResolver(FetchedCrossLinks crossLinks, IUriEnvironmentReso
 	public bool TryResolve(Action<string> errorEmitter, Uri crossLinkUri, [NotNullWhen(true)] out Uri? resolvedUri) =>
 		TryResolve(errorEmitter, _crossLinks, UriResolver, crossLinkUri, out resolvedUri);
 
+	public bool TryGetLinkMetadata(Uri crossLinkUri, [NotNullWhen(true)] out LinkMetadata? linkMetadata)
+	{
+		linkMetadata = null;
+
+		if (!_crossLinks.LinkReferences.TryGetValue(crossLinkUri.Scheme, out var sourceLinkReference))
+			return false;
+
+		var originalLookupPath = (crossLinkUri.Host + '/' + crossLinkUri.AbsolutePath.TrimStart('/')).Trim('/');
+		if (string.IsNullOrEmpty(originalLookupPath) && crossLinkUri.Host.EndsWith(".md", StringComparison.OrdinalIgnoreCase))
+			originalLookupPath = crossLinkUri.Host;
+
+		return sourceLinkReference.Links.TryGetValue(originalLookupPath, out linkMetadata);
+	}
+
 	public FetchedCrossLinks UpdateLinkReference(string repository, RepositoryLinks repositoryLinks)
 	{
 		var dictionary = _crossLinks.LinkReferences.ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

src/Elastic.Documentation/Links/RepositoryLinks.cs

@@ -17,6 +17,10 @@ public record LinkMetadata
 	[JsonPropertyName("hidden")]
 	[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
 	public bool Hidden { get; init; }
+
+	[JsonPropertyName("title")]
+	[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+	public string? Title { get; init; }
 }
 
 public record LinkSingleRedirect

src/Elastic.Markdown/Myst/InlineParsers/DiagnosticLinkInlineParser.cs

@@ -184,6 +184,14 @@ private static void ProcessCrossLink(LinkInline link, InlineProcessor processor,
 				uri, out var resolvedUri)
 			 )
 			link.Url = resolvedUri.ToString();
+
+		// Handle empty link text by trying to get title from crosslink metadata
+		if (link.FirstChild == null && context.CrossLinkResolver.TryGetLinkMetadata(uri, out var linkMetadata))
+		{
+			var title = linkMetadata.Title;
+			if (!string.IsNullOrEmpty(title))
+				_ = link.AppendChild(new LiteralInline(title));
+		}
 	}
 
 	private static void ProcessInternalLink(LinkInline link, InlineProcessor processor, ParserContext context)

tests/Elastic.Markdown.Tests/Inline/InlineLinkTests.cs

@@ -164,6 +164,31 @@ public void EmitsCrossLink()
 	}
 }
 
+public class CrossLinkEmptyTextTest(ITestOutputHelper output) : LinkTestBase(output,
+	"""
+
+	Go to [](kibana://index.md)
+	"""
+)
+{
+	[Fact]
+	public void GeneratesHtml() =>
+		// language=html
+		Html.Should().Contain(
+			"""<p>Go to <a href="https://docs-v3-preview.elastic.dev/elastic/kibana/tree/main/" hx-select-oob="#main-container" preload="mousedown">Kibana Guide</a></p>"""
+		);
+
+	[Fact]
+	public void HasNoErrors() => Collector.Diagnostics.Should().HaveCount(0);
+
+	[Fact]
+	public void EmitsCrossLink()
+	{
+		Collector.CrossLinks.Should().HaveCount(1);
+		Collector.CrossLinks.Should().Contain("kibana://index.md");
+	}
+}
+
 public class LinkWithUnresolvedInterpolationError(ITestOutputHelper output) : LinkTestBase(output,
 	"""
 	[global search field]({{this-variable-does-not-exist}}/introduction.html#kibana-navigation-search)

tests/Elastic.Markdown.Tests/TestCrossLinkResolver.cs

@@ -30,7 +30,9 @@ public TestCrossLinkResolver()
 		           	  "url_path_prefix": "/elastic/docs-content/tree/main",
 		           	  "cross_links": [],
 		           	  "links": {
-		           		"index.md": {},
+		           		"index.md": {
+		           		  "title": "Kibana Guide"
+		           		},
 		           		"get-started/index.md": {
 		           		  "anchors": [
 		           			"elasticsearch-intro-elastic-stack",
@@ -68,4 +70,10 @@ public TestCrossLinkResolver()
 
 	public bool TryResolve(Action<string> errorEmitter, Uri crossLinkUri, [NotNullWhen(true)] out Uri? resolvedUri) =>
 		CrossLinkResolver.TryResolve(errorEmitter, _crossLinks, UriResolver, crossLinkUri, out resolvedUri);
+
+	public bool TryGetLinkMetadata(Uri crossLinkUri, [NotNullWhen(true)] out LinkMetadata? linkMetadata)
+	{
+		var resolver = new CrossLinkResolver(_crossLinks, UriResolver);
+		return resolver.TryGetLinkMetadata(crossLinkUri, out linkMetadata);
+	}
 }

tests/authoring/Framework/TestCrossLinkResolver.fs

@@ -89,4 +89,8 @@ type TestCrossLinkResolver (config: ConfigurationFile) =
         member this.TryResolve(errorEmitter, crossLinkUri, [<Out>]resolvedUri : byref<Uri|null>) =
             CrossLinkResolver.TryResolve(errorEmitter, crossLinks, uriResolver, crossLinkUri, &resolvedUri)
 
+        member this.TryGetLinkMetadata(crossLinkUri, [<Out>]linkMetadata : byref<LinkMetadata|null>) =
+            let resolver = new CrossLinkResolver(crossLinks, uriResolver)
+            resolver.TryGetLinkMetadata(crossLinkUri, &linkMetadata)
+