Fix tabs and applies-switch in snippets

docs/_snippets/applies-switch.md

@@ -0,0 +1,11 @@
+::::{applies-switch}
+
+:::{applies-item} stack:
+Content for Stack
+:::
+
+:::{applies-item} serverless:
+Content for Serverless
+:::
+
+::::

docs/testing/index.md

@@ -99,3 +99,10 @@ const foo = "bar"; <1>
 ```
 
 1. This is a JavaScript code block.
+
+
+:::{include} /_snippets/applies-switch.md
+:::
+
+:::{include} /_snippets/applies-switch.md
+:::

src/Elastic.Markdown/Myst/Directives/AppliesSwitch/AppliesSwitchBlock.cs

@@ -22,15 +22,12 @@ public class AppliesSwitchBlock(DirectiveBlockParser parser, ParserContext conte
 
 	private int _index = -1;
 
-	// For simplicity, we use the line number as the index.
-	// It's not ideal, but it's unique.
-	// This is more efficient than finding the root block and then finding the index.
 	public int FindIndex()
 	{
 		if (_index > -1)
 			return _index;
 
-		_index = Line;
+		_index = GetUniqueLineIndex();
 		return _index;
 	}
 }

src/Elastic.Markdown/Myst/Directives/DirectiveBlock.cs

@@ -58,6 +58,12 @@ public abstract class DirectiveBlock(
 
 	public bool SkipValidation { get; } = context.SkipValidation;
 
+	/// <summary>
+	/// The line number of the include directive that brought this block into the document.
+	/// Null if the block is not inside an included snippet.
+	/// </summary>
+	protected int? IncludeLine { get; } = context.IncludeLine;
+
 	public int OpeningLength => Directive.Length;
 
 	public abstract string Directive { get; }
@@ -148,4 +154,12 @@ protected bool PropBool(params string[] keys)
 		return default;
 	}
 
+	/// <summary>
+	/// Gets a unique index based on the block's line number that accounts for include context.
+	/// When the block is inside an included snippet, combines the include directive's line
+	/// with the snippet line to ensure uniqueness across multiple includes and multiple blocks.
+	/// </summary>
+	/// <returns>A unique integer index suitable for generating HTML IDs.</returns>
+	protected int GetUniqueLineIndex() =>
+		IncludeLine.HasValue ? (IncludeLine.Value * 1000) + Line : Line;
 }

src/Elastic.Markdown/Myst/Directives/DirectiveHtmlRenderer.cs

@@ -361,7 +361,7 @@ private static void WriteIncludeBlock(HtmlRenderer renderer, IncludeBlock block)
 		var snippet = block.Build.ReadFileSystem.FileInfo.New(block.IncludePath);
 
 		var parentPath = block.Context.MarkdownParentPath ?? block.Context.MarkdownSourcePath;
-		var document = MarkdownParser.ParseSnippetAsync(block.Build, block.Context, snippet, parentPath, block.Context.YamlFrontMatter, default)
+		var document = MarkdownParser.ParseSnippetAsync(block.Build, block.Context, snippet, parentPath, block.Context.YamlFrontMatter, default, block.Line)
 			.GetAwaiter().GetResult();
 
 		var html = document.ToHtml(MarkdownParser.Pipeline);

src/Elastic.Markdown/Myst/Directives/Tabs/TabSetBlock.cs

@@ -19,15 +19,12 @@ public class TabSetBlock(DirectiveBlockParser parser, ParserContext context)
 
 	private int _index = -1;
 
-	// For simplicity, we use the line number as the index.
-	// It's not ideal, but it's unique.
-	// This is more efficient than finding the root block and then finding the index.
 	public int FindIndex()
 	{
 		if (_index > -1)
 			return _index;
 
-		_index = Line;
+		_index = GetUniqueLineIndex();
 		return _index;
 	}
 }

src/Elastic.Markdown/Myst/MarkdownParser.cs

@@ -83,7 +83,7 @@ public static MarkdownDocument ParseMarkdownStringAsync(BuildContext build, IPar
 	}
 
 	public static Task<MarkdownDocument> ParseSnippetAsync(BuildContext build, IParserResolvers resolvers, IFileInfo path, IFileInfo parentPath,
-		YamlFrontMatter? matter, Cancel ctx)
+		YamlFrontMatter? matter, Cancel ctx, int? includeLine = null)
 	{
 		var state = new ParserState(build)
 		{
@@ -93,7 +93,8 @@ public static Task<MarkdownDocument> ParseSnippetAsync(BuildContext build, IPars
 			TryFindDocumentByRelativePath = resolvers.TryFindDocumentByRelativePath,
 			CrossLinkResolver = resolvers.CrossLinkResolver,
 			NavigationTraversable = resolvers.NavigationTraversable,
-			ParentMarkdownPath = parentPath
+			ParentMarkdownPath = parentPath,
+			IncludeLine = includeLine
 		};
 		var context = new ParserContext(state);
 		return ParseAsync(path, context, Pipeline, ctx);

src/Elastic.Markdown/Myst/ParserContext.cs

@@ -54,6 +54,12 @@ public record ParserState(BuildContext Build) : ParserResolvers
 
 	public IFileInfo? ParentMarkdownPath { get; init; }
 	public bool SkipValidation { get; init; }
+
+	/// <summary>
+	/// The line number of the include directive in the parent file.
+	/// Used to generate unique IDs for blocks within included snippets.
+	/// </summary>
+	public int? IncludeLine { get; init; }
 }
 
 public class ParserContext : MarkdownParserContext, IParserResolvers
@@ -72,13 +78,20 @@ public class ParserContext : MarkdownParserContext, IParserResolvers
 	public IReadOnlyDictionary<string, string> ContextSubstitutions { get; }
 	public INavigationTraversable NavigationTraversable { get; }
 
+	/// <summary>
+	/// The line number of the include directive in the parent file.
+	/// Used to generate unique IDs for blocks within included snippets.
+	/// </summary>
+	public int? IncludeLine { get; }
+
 	public ParserContext(ParserState state)
 	{
 		Build = state.Build;
 		Configuration = state.Configuration;
 		YamlFrontMatter = state.YamlFrontMatter;
 		SkipValidation = state.SkipValidation;
 		MarkdownParentPath = state.ParentMarkdownPath;
+		IncludeLine = state.IncludeLine;
 
 		CrossLinkResolver = state.CrossLinkResolver;
 		MarkdownSourcePath = state.MarkdownSourcePath;

src/Elastic.Markdown/Myst/Renderers/LlmMarkdown/LlmBlockRenderers.cs

@@ -520,7 +520,7 @@ private void WriteIncludeBlock(LlmMarkdownRenderer renderer, IncludeBlock block)
 			try
 			{
 				var parentPath = block.Context.MarkdownParentPath ?? block.Context.MarkdownSourcePath;
-				var document = MarkdownParser.ParseSnippetAsync(block.Build, block.Context, snippet, parentPath, block.Context.YamlFrontMatter, Cancel.None)
+				var document = MarkdownParser.ParseSnippetAsync(block.Build, block.Context, snippet, parentPath, block.Context.YamlFrontMatter, Cancel.None, block.Line)
 					.GetAwaiter().GetResult();
 				_ = renderer.Render(document);
 			}

tests/Elastic.Markdown.Tests/FileInclusion/IncludedAppliesSwitchTests.cs

@@ -0,0 +1,106 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// 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 System.IO.Abstractions.TestingHelpers;
+using Elastic.Markdown.Myst.Directives.Include;
+using Elastic.Markdown.Tests.Directives;
+using FluentAssertions;
+
+namespace Elastic.Markdown.Tests.FileInclusion;
+
+/// <summary>
+/// Tests that when the same snippet containing applies-switch is included multiple times,
+/// each include generates unique IDs to avoid HTML ID collisions.
+/// </summary>
+public class IncludedAppliesSwitchTests(ITestOutputHelper output) : DirectiveTest<IncludeBlock>(output,
+"""
+:::{include} _snippets/applies-switch.md
+:::
+
+Some content between includes.
+
+:::{include} _snippets/applies-switch.md
+:::
+"""
+)
+{
+	protected override void AddToFileSystem(MockFileSystem fileSystem)
+	{
+		// language=markdown
+		var snippet =
+"""
+::::{applies-switch}
+:::{applies-item} stack:
+Content for Stack
+:::
+:::{applies-item} serverless:
+Content for Serverless
+:::
+::::
+""";
+		fileSystem.AddFile(@"docs/_snippets/applies-switch.md", snippet);
+	}
+
+	[Fact]
+	public void ParsesBlock() => Block.Should().NotBeNull();
+
+	[Fact]
+	public void EachIncludeHasUniqueIds()
+	{
+		// First include at line 2: (2 * 1000) + 0 = 2000
+		// Second include at line 7: (7 * 1000) + 0 = 7000
+		Html.Should().Contain("applies-switch-item-2000-0");
+		Html.Should().Contain("applies-switch-item-2000-1");
+		Html.Should().Contain("applies-switch-set-2000");
+
+		Html.Should().Contain("applies-switch-item-7000-0");
+		Html.Should().Contain("applies-switch-item-7000-1");
+		Html.Should().Contain("applies-switch-set-7000");
+	}
+}
+
+/// <summary>
+/// Tests that a snippet with multiple applies-switches generates unique IDs for each one.
+/// </summary>
+public class IncludedMultipleAppliesSwitchTests(ITestOutputHelper output) : DirectiveTest<IncludeBlock>(output,
+"""
+:::{include} _snippets/multi-applies-switch.md
+:::
+"""
+)
+{
+	protected override void AddToFileSystem(MockFileSystem fileSystem)
+	{
+		// language=markdown
+		var snippet =
+"""
+::::{applies-switch}
+:::{applies-item} stack:
+First switch - Stack
+:::
+::::
+
+Some content between.
+
+::::{applies-switch}
+:::{applies-item} serverless:
+Second switch - Serverless
+:::
+::::
+""";
+		fileSystem.AddFile(@"docs/_snippets/multi-applies-switch.md", snippet);
+	}
+
+	[Fact]
+	public void ParsesBlock() => Block.Should().NotBeNull();
+
+	[Fact]
+	public void EachAppliesSwitchHasUniqueIds()
+	{
+		// Include at line 2, first applies-switch at line 0: (2 * 1000) + 0 = 2000
+		// Include at line 2, second applies-switch at line 8: (2 * 1000) + 8 = 2008
+		Html.Should().Contain("applies-switch-set-2000");
+		Html.Should().Contain("applies-switch-set-2008");
+	}
+}

tests/Elastic.Markdown.Tests/FileInclusion/IncludedTabSetTests.cs

@@ -0,0 +1,106 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// 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 System.IO.Abstractions.TestingHelpers;
+using Elastic.Markdown.Myst.Directives.Include;
+using Elastic.Markdown.Tests.Directives;
+using FluentAssertions;
+
+namespace Elastic.Markdown.Tests.FileInclusion;
+
+/// <summary>
+/// Tests that when the same snippet containing tab-set is included multiple times,
+/// each include generates unique IDs to avoid HTML ID collisions.
+/// </summary>
+public class IncludedTabSetTests(ITestOutputHelper output) : DirectiveTest<IncludeBlock>(output,
+"""
+:::{include} _snippets/tab-set.md
+:::
+
+Some content between includes.
+
+:::{include} _snippets/tab-set.md
+:::
+"""
+)
+{
+	protected override void AddToFileSystem(MockFileSystem fileSystem)
+	{
+		// language=markdown
+		var snippet =
+"""
+::::{tab-set}
+:::{tab-item} First
+Content for first tab
+:::
+:::{tab-item} Second
+Content for second tab
+:::
+::::
+""";
+		fileSystem.AddFile(@"docs/_snippets/tab-set.md", snippet);
+	}
+
+	[Fact]
+	public void ParsesBlock() => Block.Should().NotBeNull();
+
+	[Fact]
+	public void EachIncludeHasUniqueIds()
+	{
+		// First include at line 2: (2 * 1000) + 0 = 2000
+		// Second include at line 7: (7 * 1000) + 0 = 7000
+		Html.Should().Contain("tabs-item-2000-0");
+		Html.Should().Contain("tabs-item-2000-1");
+		Html.Should().Contain("tabs-set-2000");
+
+		Html.Should().Contain("tabs-item-7000-0");
+		Html.Should().Contain("tabs-item-7000-1");
+		Html.Should().Contain("tabs-set-7000");
+	}
+}
+
+/// <summary>
+/// Tests that a snippet with multiple tab-sets generates unique IDs for each one.
+/// </summary>
+public class IncludedMultipleTabSetTests(ITestOutputHelper output) : DirectiveTest<IncludeBlock>(output,
+"""
+:::{include} _snippets/multi-tab-set.md
+:::
+"""
+)
+{
+	protected override void AddToFileSystem(MockFileSystem fileSystem)
+	{
+		// language=markdown
+		var snippet =
+"""
+::::{tab-set}
+:::{tab-item} First
+First tab set
+:::
+::::
+
+Some content between.
+
+::::{tab-set}
+:::{tab-item} Second
+Second tab set
+:::
+::::
+""";
+		fileSystem.AddFile(@"docs/_snippets/multi-tab-set.md", snippet);
+	}
+
+	[Fact]
+	public void ParsesBlock() => Block.Should().NotBeNull();
+
+	[Fact]
+	public void EachTabSetHasUniqueIds()
+	{
+		// Include at line 2, first tab-set at line 0: (2 * 1000) + 0 = 2000
+		// Include at line 2, second tab-set at line 8: (2 * 1000) + 8 = 2008
+		Html.Should().Contain("tabs-set-2000");
+		Html.Should().Contain("tabs-set-2008");
+	}
+}