denoland/deno · error

build failed (exit code: )

Error message

{} build failed (exit code: {})

What it means

`deno desktop` detects the web framework in the project and delegates the build to the framework's own build command (e.g. `vite build`, `next build`) via std::process::Command. This error reports that the child build process exited with a non-zero status; the actual failure reason was printed by the framework's own tooling to the console just before this message.

Solutions

  1. Run the framework's build directly (e.g. `npm run build` or `npx vite build`) to see the full error output and fix what it reports
  2. Install dependencies first (`npm install` or `deno install`), then retry `deno desktop`
  3. Verify required build-time environment variables and the Node.js version the framework needs

Example fix

# before
deno desktop          # Next.js build failed (exit code: 1)

# after
npm run build         # shows the real error (e.g. type error in src/app/page.tsx)
# fix the reported error, then:
deno desktop
Defensive patterns

Strategy: validation

Validate before calling

# prove the framework build passes before invoking deno desktop:
npm install && npm run build   # or: npx vite build / npm run build
# only then:
deno desktop

Try / catch

Wrap `deno desktop` invocation; on failure parse 'build failed (exit code: N)', then re-run the raw build command (`npm run build`) to surface the underlying errors for triage.

Prevention

When it happens

Trigger: Any framework build failure: TypeScript/ESLint errors inside the project, missing dependencies (node_modules absent), missing build-time env vars, out-of-memory, or a Node.js version incompatible with the framework. The spawn itself succeeded (a spawn failure would give the 'Failed to run build command' context instead); the process ran and returned a failing exit code.

Common situations: Running `deno desktop` before installing dependencies (npm install / deno install); projects whose `npm run build` fails on type errors; missing .env values needed at build time; local Node version differs from the one CI pins.

Related errors

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/62e7832067225f67. Report an issue: GitHub.

Appendix: source

Thrown at cli/tools/framework.rs:148

  dir: &Path,
) -> Result<(), AnyError> {
  let Some(build_cmd) = &detection.build_command else {
    return Ok(());
  };
  log::info!(
    "{} {} project...",
    deno_terminal::colors::green("Building"),
    detection.name,
  );
  let status = std::process::Command::new(&build_cmd[0])
    .args(&build_cmd[1..])
    .current_dir(dir)
    .status()
    .with_context(|| {
      format!("Failed to run build command: {}", build_cmd.join(" "))
    })?;
  if !status.success() {
    deno_core::anyhow::bail!(
      "{} build failed (exit code: {})",
      detection.name,
      status.code().unwrap_or(-1)
    );
  }
  Ok(())
}

/// Detect a web framework in the given directory.
///
/// Detection priority:
/// 1. Config-file based detection (highest priority)
/// 2. Package.json dependency-based detection
/// 3. deno.json import-based detection
pub fn detect_framework(
  dir: &Path,
) -> Result<Option<FrameworkDetection>, AnyError> {
  // --- Config-file based detection (highest priority) ---

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