meziantou/meziantou.framework/use-fullpath

# .NET 10+
dotnet package add Meziantou.Framework.FullPath
 
# .NET 9 and earlier
dotnet add package Meziantou.Framework.FullPath

// From a string (relative paths are resolved against the current directory)
FullPath path = FullPath.FromPath("demo");
 
// Well-known locations
FullPath temp = FullPath.GetTempPath();
FullPath cwd  = FullPath.CurrentDirectory();
FullPath docs = FullPath.GetFolderPath(Environment.SpecialFolder.MyDocuments);

FullPath root = FullPath.FromPath("/repo");
 
// / operator (preferred for readability)
FullPath file = root / "src" / "Program.cs";
 
// Combine (useful when the number of segments is dynamic)
FullPath file2 = FullPath.Combine(root, "src", "Program.cs");

// == and != use the OS-default comparison
if (pathA == pathB) { /* same file */ }
 
// Explicit case-sensitivity control
bool equal = pathA.Equals(pathB, ignoreCase: false);

FullPath file = FullPath.FromPath("/repo/src/Program.cs");
 
FullPath dir       = file.Parent;              // /repo/src
string   name      = file.Name;               // Program.cs
string   nameNoExt = file.NameWithoutExtension; // Program
string   ext       = file.Extension;           // .cs
 
FullPath renamed = file.ChangeExtension(".vb"); // /repo/src/Program.vb

FullPath root = FullPath.FromPath("/repo");
FullPath file = root / "src" / "Program.cs";
 
bool isChild = file.IsChildOf(root); // true

FullPath root = FullPath.FromPath("/repo");
FullPath file = root / "src" / "Program.cs";
 
string relative = file.MakePathRelativeTo(root); // src/Program.cs (or src\Program.cs on Windows)

FullPath start = FullPath.FromPath("/repo/src/deep/nested");
 
// Find the first ancestor (or self) matching a predicate
if (start.TryFindFirstAncestorOrSelf(
        p => File.Exists(p / ".editorconfig"), out FullPath match))
{
    // match is the closest directory containing .editorconfig
}
 
// Shortcut: find the Git repository root
if (start.TryFindGitRepositoryRoot(out FullPath gitRoot))
{
    // gitRoot is the closest directory containing .git
}

FullPath config = root / "appsettings.json";
 
// No .Value or .ToString() needed
string json = File.ReadAllText(config);
File.WriteAllText(config, json);
Directory.CreateDirectory(config.Parent);

logger.LogInformation("Loading config from {Path}", config.Value);

FullPath output = root / "artifacts" / "report.html";
output.CreateParentDirectory(); // creates "artifacts" if it doesn't exist
File.WriteAllText(output, html);

public sealed class AppSettings
{
    public FullPath OutputDirectory { get; set; }
}
 
// { "OutputDirectory": "C:\\repo\\output" }
var settings = JsonSerializer.Deserialize<AppSettings>(json);

// ❌ Ambiguous — is this a full path or a relative fragment?
void Export(string outputPath) { }
 
// ✅ Clear contract — the caller must provide a resolved path
void Export(FullPath outputPath) { }

var seen = new HashSet<FullPath>(); // uses default OS comparison
var map  = new Dictionary<FullPath, int>();
 
// Explicit comparer if needed
var caseSensitiveSet = new HashSet<FullPath>(FullPathComparer.CaseSensitive);