stride3d/stride · error · ArgumentException

A file path cannot end with with directory char '\' or '/'…

Error message

A file path cannot end with with directory char '\' or '/', or a volume separator ':'.

What it means

The internal UPath(string, bool) constructor throws ArgumentException when representing a FILE path whose string ends with a directory separator ('\\' or '/') or a volume separator (':'). A file path must point to a named file, so trailing separator characters make it ambiguous/invalid. Directory paths are exempt via the isDirectory flag.

Solutions

Trim trailing separators from the string before constructing the UPath
Pass isDirectory:true if the path really denotes a directory
Use UDirectory/UFile typed helpers instead of raw string construction

Example fix

// before
var path = new UPath("assets/model/", false); // throws
// after
var path = new UPath("assets/model/".TrimEnd('/', '\\'), false);

Defensive patterns

Strategy: validation

Validate before calling

if (!isDirectory && filePath != null)
    filePath = filePath.TrimEnd('/', '\\', ':');
var path = new UPath(filePath, isDirectory);

Prevention

Trim trailing separators when building paths via string concatenation
Use UFile/UDirectory typed paths instead of raw strings
Validate user-supplied paths before conversion

When it happens

Trigger: Constructing UPath for a file from a string like "C:/dir/file/" or "/assets/model:" — trailing '/' or ':' with isDirectory=false.

Common situations: String concatenation building paths and leaving a trailing slash, copy-pasting a directory path and treating it as a file, parsing user-supplied paths without trimming.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/6ba4b54de10643df. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Design/IO/UPath.cs:62

    /// The directory separator string '/' used to separate directory in an url.
    /// </summary>
    public const string DirectorySeparatorString = "/";

    /// <summary>
    /// The directory separator string '\' used to separate directory in an url.
    /// </summary>
    public const string DirectorySeparatorStringAlt = "\\";

    /// <summary>
    /// Initializes a new instance of the <see cref="UPath" /> class from a file path.
    /// </summary>
    /// <param name="filePath">The full path to a file.</param>
    /// <param name="isDirectory">if set to <c>true</c> the filePath is considered as a directory and not a filename.</param>
    internal UPath(string? filePath, bool isDirectory)
    {
        if (!isDirectory && filePath != null && (filePath.EndsWith(DirectorySeparatorChar) || filePath.EndsWith(DirectorySeparatorCharAlt) || filePath.EndsWith(Path.VolumeSeparatorChar)))
        {
            throw new ArgumentException("A file path cannot end with with directory char '\\' or '/', or a volume separator ':'.");
        }

        FullPath = Decode(filePath, isDirectory, out DriveSpan, out DirectorySpan, out NameSpan, out ExtensionSpan);
        hashCode = ComputeStringHashCodeCaseInsensitive(FullPath);
    }

    protected UPath(string fullPath, StringSpan driveSpan, StringSpan directorySpan)
    {
#if NET6_0_OR_GREATER
        ArgumentNullException.ThrowIfNull(fullPath);
#else
        if (fullPath is null) throw new ArgumentNullException(nameof(fullPath));
#endif
        FullPath = fullPath;
        hashCode = ComputeStringHashCodeCaseInsensitive(fullPath);
        DriveSpan = driveSpan;
        DirectorySpan = directorySpan;
    }

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