microsoft/aspire · error · InvalidOperationException

Deno command-line options configured with the WithDeno*…

Error message

Deno command-line options configured with the WithDeno* methods cannot be combined with package manager '{packageManager.ExecutableName}' on resource '{resource.Name}'. Remove the WithDeno* options or use WithDeno().

What it means

Deno-specific command-line options (WithDeno* methods producing a DenoCommandLineAnnotation) are only meaningful when the resource's package manager is deno. Combining them with another package manager produces a contradictory configuration, so AddDenoApp throws when both a DenoCommandLineAnnotation and a non-deno JavaScriptPackageManagerAnnotation are present.

Solutions

  1. Remove the WithDeno* option calls from the resource.
  2. Call WithDeno() to switch the resource's package manager to deno before applying Deno options.
  3. Delete the stale package-manager annotation/detection source (e.g. remove package.json or stop auto-detection) if it is leftover.

Example fix

// before
builder.AddJavaScriptApp("app", "main.ts").WithNpm().WithDenoConfig("deno.json");
// after
builder.AddJavaScriptApp("app", "main.ts").WithDeno(deno => deno.WithConfig("deno.json"));
Defensive patterns

Strategy: validation

Validate before calling

// detect the conflict before calling WithDeno* methods
var hasDenoOptions = resource.TryGetLastAnnotation<DenoCommandLineAnnotation>(out _);
resource.TryGetLastAnnotation<JavaScriptPackageManagerAnnotation>(out var pm);
if (hasDenoOptions && pm is not null && pm.ExecutableName != "deno")
{
    throw new InvalidOperationException($"Deno options conflict with package manager {pm.ExecutableName}.");
}

Try / catch

try
{
    app.WithDeno(deno => deno.WithConfig("deno.json"));
}
catch (InvalidOperationException ex) when (ex.Message.Contains("cannot be combined with package manager"))
{
    // drop the WithDeno* options or switch the resource to WithDeno()
}

Prevention

When it happens

Trigger: Calling WithDeno* options (e.g. WithDenoConfig, WithDenoScript, WithDenoNodeModules) on a resource whose package manager annotation resolves to npm/pnpm/yarn/bun — for example AddJavaScriptApp on a package.json project, then adding Deno options.

Common situations: Refactoring a Node app to Deno where package.json still drives package-manager detection; a shared helper that appends Deno flags to every JavaScript resource; typos where WithDeno() was meant to be called instead.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/365101659d710d4f. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.JavaScript/DenoHostingExtensions.cs:1065

            normalizedSegments.Add(segment);
        }

        normalizedPath = string.Join('/', normalizedSegments);
        return true;
    }

    /// <summary>
    /// Rejects Deno-specific command-line options when a non-Deno package manager is the effective launcher.
    /// The <c>WithDeno*</c> flags produce a Deno argument vector (for example <c>run -A --watch main.ts</c>),
    /// which is meaningless once the command is switched to another package manager such as <c>npm</c>.
    /// </summary>
    private static void ThrowIfDenoOptionsConflictWithPackageManager(IResource resource)
    {
        if (resource.TryGetLastAnnotation<DenoCommandLineAnnotation>(out _) &&
            resource.TryGetLastAnnotation<JavaScriptPackageManagerAnnotation>(out var packageManager) &&
            !string.Equals(packageManager.ExecutableName, "deno", StringComparison.Ordinal))
        {
            throw new InvalidOperationException($"Deno command-line options configured with the WithDeno* methods cannot be combined with package manager '{packageManager.ExecutableName}' on resource '{resource.Name}'. Remove the WithDeno* options or use WithDeno().");
        }
    }

    /// <summary>
    /// Converts a host-relative path to normalized POSIX form for the generated Linux container stages.
    /// </summary>
    /// <remarks>
    /// AppHost-configured paths use the host separator, so on Windows a nested entrypoint is configured as
    /// <c>src\main.ts</c>. Emitting that verbatim into <c>deno cache</c> or <c>ENTRYPOINT</c> makes Linux treat
    /// the whole string as a single file name and the container fails to start.
    /// </remarks>
    private static string ToDenoContainerPath(string path)
        => TryNormalizeDenoContainerRelativePath(path, out var normalizedPath)
            ? normalizedPath
            : path.Replace('\\', '/');

    // Deno options that Aspire emits as a separate flag/value pair where the value is a path that must be
    // rewritten to its container form.

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