clockworklabs/SpacetimeDB · error · anyhow::Error

The selected C# build path requires the .NET {desired_sdk_ma

Error message

The selected C# build path requires the .NET {desired_sdk_major} SDK, but the active SDK is .NET {active}.
Update {} to select the .NET {desired_sdk_major} SDK, or run `spacetime init --dotnet-version {desired_sdk_major}` to create a project configured for this SDK.
Expected global.json contents:
{}

What it means

Error "The selected C# build path requires the .NET {desired_sdk_major} SDK, but the active SDK is .NET {active}. Update {} to select the .NET {desired_sdk_major} SDK, or run `spacetime init --dotnet-version {desired_sdk_major}` to create a project configured for this SDK. Expected global.json contents: {}" thrown in clockworklabs/SpacetimeDB.

Source

Thrown at crates/cli/src/tasks/csharp.rs:261

                .unwrap_or_else(|| "<unknown>".to_string());
            anyhow::bail!(
                "Unsupported .NET SDK version: {}. SpacetimeDB requires .NET SDK 8.0 or 10.0.\n\
                 If you have multiple versions installed, configure your project using \
                 https://learn.microsoft.com/en-us/dotnet/core/tools/global-json, \
                 or use --dotnet-version to specify the target version explicitly.",
                selected_version
            );
        }
    };

    let desired_sdk_major = match build_path {
        CsharpBuildPath::Net8Jit | CsharpBuildPath::Net8Aot => 8,
        CsharpBuildPath::Net10Aot => 10,
    };
    let active_sdk_major = dotnet_version_str.as_deref().and_then(parse_major_version);
    if active_sdk_major != Some(desired_sdk_major) {
        let active = dotnet_version_str.as_deref().map(str::trim).unwrap_or("<unknown>");
        anyhow::bail!(
            "The selected C# build path requires the .NET {desired_sdk_major} SDK, but the active SDK is .NET {active}.\n\
             Update {} to select the .NET {desired_sdk_major} SDK, or run `spacetime init --dotnet-version {desired_sdk_major}` to create a project configured for this SDK.\n\
             Expected global.json contents:\n{}",
            project_path.join("global.json").display(),
            dotnet_global_json(desired_sdk_major)?
        );
    }

    // Manage the EXPERIMENTAL_WASM_AOT environment variable for MSBuild.
    // - Net8Aot / Net10Aot: must SET it — the ILCompiler.LLVM.targets import in
    //   SpacetimeDB.Runtime.targets is gated on this env var. Without it, the NativeAOT
    //   toolchain is not activated and dotnet produces managed DLLs instead of a .wasm.
    // - Net8Jit: must UNSET it — prevents MSBuild from incorrectly enabling NativeAOT mode
    //   when the env var is set globally (e.g., in CI).
    match &build_path {
        CsharpBuildPath::Net8Aot | CsharpBuildPath::Net10Aot => {
            // SAFETY: We are single-threaded at this point and no other code is reading
            // this environment variable concurrently.

View on GitHub (pinned to 524b4487d9)

When it happens

Trigger: Thrown at crates/cli/src/tasks/csharp.rs:261 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of clockworklabs/SpacetimeDB@524b4487d9 (2026-08-16). Data as JSON: /api/errors/b92cea7902394afa. Report an issue: GitHub.