stride3d/stride · error · ArgumentException

Expecting an absolute directory

Error message

Expecting an absolute directory

What it means

UPath.MakeRelative throws ArgumentException when the anchorDirectory parameter is not an absolute directory. Making a path relative requires the anchor to be a fully-qualified absolute directory; passing a relative path or a file path cannot define a valid base.

Solutions

1. Resolve the anchor to an absolute path (combine with the project/mount root) before calling MakeRelative
2. Ensure the anchor is a UDirectory, not a UFile
3. Check anchorDirectory.IsAbsolute before calling

Example fix

// before
var rel = filePath.MakeRelative(new UDirectory("assets")); // throws: not absolute
// after
var anchor = new UDirectory(Path.Combine(projectRoot, "assets"));
var rel = filePath.MakeRelative(anchor);

if (!anchorDirectory.IsAbsolute)
    anchorDirectory = new UDirectory(Path.Combine(rootPath, anchorDirectory.ToString()));
var rel = filePath.MakeRelative(anchorDirectory);

When it happens

Trigger: Calling path.MakeRelative(relativeOrNonAbsolutePath) where the anchor is relative (e.g. "assets/textures" without root), or a UFile rather than a UDirectory.

Common situations: Building paths from user/project config where the base directory is stored as a relative path, forgetting to resolve the anchor against the project root first.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• A file path cannot end with with directory char '\' or '/'…
• Path should have no drive information/or both drive…
• Operation 'Read' is not supported
• Operation 'Write' is not supported
• The provided path is not a valid path name.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/0d83f3dcaffec2fe. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Design/IO/UPath.cs:360

    /// <returns>A relative path of this instance to the anchor directory.</returns>
    public UPath MakeRelative(UDirectory anchorDirectory)
    {
#if NET6_0_OR_GREATER
        ArgumentNullException.ThrowIfNull(anchorDirectory);
#else
        if (anchorDirectory is null) throw new ArgumentNullException(nameof(anchorDirectory));
#endif

        // If the toRelativize path is already relative, don't bother
        if (IsRelative)
        {
            return this;
        }

        // If anchor directory is not absolute directory, throw an error
        if (!anchorDirectory.IsAbsolute)
        {
            throw new ArgumentException("Expecting an absolute directory", nameof(anchorDirectory));
        }

        if (anchorDirectory.HasDrive != HasDrive)
        {
            throw new InvalidOperationException("Path should have no drive information/or both drive information simultaneously");
        }

        // Return a "." when the directory is the same
        if (this is UDirectory && anchorDirectory == this)
        {
            return UDirectory.This;
        }

        // Get the full path of the anchor directory
        var anchorPath = anchorDirectory.FullPath;

        // Builds an absolute path for the toRelative path (directory-only)
        var absoluteFile = Combine(anchorDirectory, this);

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