Consolidate git root discovery and remove Paths.GitCommonRoot static

Three changes:

1. FileSystemFactory.FindGitRoot removed — ForPath/ForPathWrite now call
   Paths.FindGitRoot, which is the single canonical git-root walker.

2. Paths.DetermineSourceDirectoryRoot simplified — the loop body had a
   dead branch (checked GetDirectories.Length == 0 in the while condition
   then re-checked inside). Rewritten to a clean while-loop matching
   FindGitRoot's structure; semantics unchanged.

3. Paths.GitCommonRoot static field and InitGitCommonRoot removed —
   the static ran complex logic (ScopedFileSystem creation + file read)
   at class init time and was only used by AssembleContext and CodexContext.
   Both now call Paths.ResolveGitCommonRoot(readFileSystem, workingRoot)
   directly, which is already public and takes explicit dependencies.
   Paths.cs no longer references Nullean.ScopedFileSystem.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: Mpdreamz

src/Elastic.Codex/CodexContext.cs

@@ -46,7 +46,9 @@ public CodexContext(
 		ReadFileSystem = readFileSystem;
 		WriteFileSystem = writeFileSystem;
 
-		var defaultCheckoutDirectory = Path.Join(Paths.GitCommonRoot.FullName, ".artifacts", "codex", "clone");
+		var workingRoot = ReadFileSystem.DirectoryInfo.New(Paths.WorkingDirectoryRoot.FullName);
+		var gitCommonRoot = Paths.ResolveGitCommonRoot(ReadFileSystem, workingRoot);
+		var defaultCheckoutDirectory = Path.Join(gitCommonRoot.FullName, ".artifacts", "codex", "clone");
 		CheckoutDirectory = ReadFileSystem.DirectoryInfo.New(checkoutDirectory ?? defaultCheckoutDirectory);
 
 		var defaultOutputDirectory = Path.Join(Paths.WorkingDirectoryRoot.FullName, ".artifacts", "codex", "docs");

src/Elastic.Documentation.Configuration/FileSystemFactory.cs

@@ -107,7 +107,7 @@ public static ScopedFileSystem ForPath(string? path)
 	{
 		if (path is null)
 			return RealRead;
-		var root = FindGitRoot(path);
+		var root = Paths.FindGitRoot(path);
 		return new ScopedFileSystem(new FileSystem(), new ScopedFileSystemOptions([root, Paths.ApplicationData.FullName])
 		{
 			AllowedHiddenFolderNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { ".git", ".artifacts" },
@@ -126,7 +126,7 @@ public static ScopedFileSystem ForPathWrite(string? path, string? output = null)
 		if (path is null && output is null)
 			return RealWrite;
 
-		var gitRoot = path is not null ? FindGitRoot(path) : Paths.WorkingDirectoryRoot.FullName;
+		var gitRoot = path is not null ? Paths.FindGitRoot(path) : Paths.WorkingDirectoryRoot.FullName;
 		var roots = new List<string> { gitRoot, Paths.ApplicationData.FullName };
 
 		if (output is not null)
@@ -143,20 +143,4 @@ public static ScopedFileSystem ForPathWrite(string? path, string? output = null)
 		});
 	}
 
-	// Walks up from startPath to find the nearest .git directory or file (worktree support).
-	// Uses System.IO directly — acceptable bootstrap, same pattern as Paths.DetermineWorkingDirectoryRoot.
-	private static string FindGitRoot(string startPath)
-	{
-		var resolved = Path.IsPathRooted(startPath) ? startPath : Path.GetFullPath(startPath);
-		var dir = Directory.Exists(resolved)
-			? new DirectoryInfo(resolved)
-			: new DirectoryInfo(Path.GetDirectoryName(resolved) ?? resolved);
-		while (dir != null)
-		{
-			if (dir.GetDirectories(".git").Length > 0 || dir.GetFiles(".git").Length > 0)
-				return dir.FullName;
-			dir = dir.Parent;
-		}
-		return Path.GetPathRoot(resolved) ?? resolved;
-	}
 }

src/Elastic.Documentation.Configuration/Paths.cs

@@ -4,18 +4,35 @@
 
 using System.Diagnostics.CodeAnalysis;
 using System.IO.Abstractions;
-using Nullean.ScopedFileSystem;
 
 namespace Elastic.Documentation.Configuration;
 
 public static class Paths
 {
 	public static readonly DirectoryInfo WorkingDirectoryRoot = DetermineWorkingDirectoryRoot();
 
-	public static readonly DirectoryInfo GitCommonRoot = InitGitCommonRoot();
-
 	public static readonly DirectoryInfo ApplicationData = GetApplicationFolder();
 
+	/// <summary>
+	/// Walks up from <paramref name="startPath"/> until a <c>.git</c> directory or file
+	/// (worktree pointer) is found and returns that ancestor. Returns <paramref name="startPath"/>
+	/// itself when no git root is found.
+	/// </summary>
+	public static string FindGitRoot(string startPath)
+	{
+		var resolved = Path.IsPathRooted(startPath) ? startPath : Path.GetFullPath(startPath);
+		var dir = Directory.Exists(resolved)
+			? new DirectoryInfo(resolved)
+			: new DirectoryInfo(Path.GetDirectoryName(resolved) ?? resolved);
+		while (dir != null)
+		{
+			if (dir.GetDirectories(".git").Length > 0 || dir.GetFiles(".git").Length > 0)
+				return dir.FullName;
+			dir = dir.Parent;
+		}
+		return resolved;
+	}
+
 	private static DirectoryInfo DetermineWorkingDirectoryRoot()
 	{
 		var directory = new DirectoryInfo(Directory.GetCurrentDirectory());
@@ -33,22 +50,23 @@ private static DirectoryInfo DetermineWorkingDirectoryRoot()
 		return directory ?? new DirectoryInfo(Directory.GetCurrentDirectory());
 	}
 
+	/// <summary>
+	/// Walks up from <paramref name="sourceDirectory"/> via <see cref="IFileSystem"/> until a
+	/// <c>.git</c> directory or file (worktree pointer) is found.
+	/// </summary>
 	public static IDirectoryInfo? DetermineSourceDirectoryRoot(IDirectoryInfo sourceDirectory)
 	{
-		IDirectoryInfo? sourceRoot = null;
 		var directory = sourceDirectory;
-		while (directory != null && directory.GetDirectories(".git").Length == 0)
+		while (directory != null)
 		{
 			if (directory.GetDirectories(".git").Length > 0)
-				break;
+				return directory;
 			// support for git worktrees
 			if (directory.GetFiles(".git").Length > 0)
-				break;
-
+				return directory;
 			directory = directory.Parent;
 		}
-		sourceRoot ??= directory;
-		return sourceRoot;
+		return null;
 	}
 
 	/// <summary>Resolves the root of the main git repository, following worktree links when present. Disabled on CI.</summary>
@@ -80,18 +98,6 @@ public static IDirectoryInfo ResolveGitCommonRoot(IFileSystem fileSystem, IDirec
 		return dir?.Parent ?? workingDirectoryRoot;
 	}
 
-	private static DirectoryInfo InitGitCommonRoot()
-	{
-		var root = WorkingDirectoryRoot.FullName;
-		var fs = new ScopedFileSystem(new FileSystem(), new ScopedFileSystemOptions(root)
-		{
-			AllowedHiddenFileNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { ".git" },
-			AllowedHiddenFolderNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { ".git" }
-		});
-		var rootDir = fs.DirectoryInfo.New(root);
-		return new DirectoryInfo(ResolveGitCommonRoot(fs, rootDir).FullName);
-	}
-
 	/// Used in debug to locate static folder, so we can change js/css files while the server is running
 	public static DirectoryInfo? GetSolutionDirectory()
 	{

src/services/Elastic.Documentation.Assembler/AssembleContext.cs

@@ -89,7 +89,9 @@ public AssembleContext(
 		Endpoints.Environment = environment;
 
 		var contentSource = Environment.ContentSource.ToStringFast(true);
-		var defaultCheckoutDirectory = Path.Join(Paths.GitCommonRoot.FullName, ".artifacts", "checkouts", contentSource);
+		var workingRoot = ReadFileSystem.DirectoryInfo.New(Paths.WorkingDirectoryRoot.FullName);
+		var gitCommonRoot = Paths.ResolveGitCommonRoot(ReadFileSystem, workingRoot);
+		var defaultCheckoutDirectory = Path.Join(gitCommonRoot.FullName, ".artifacts", "checkouts", contentSource);
 		CheckoutDirectory = ReadFileSystem.DirectoryInfo.New(checkoutDirectory ?? defaultCheckoutDirectory);
 		var defaultOutputDirectory = Path.Join(Paths.WorkingDirectoryRoot.FullName, ".artifacts", "assembly");
 		OutputDirectory = ReadFileSystem.DirectoryInfo.New(output ?? defaultOutputDirectory);