denoland/deno · error

No valid icon images found for .ico

Error message

No valid icon images found for .ico

What it means

Error "No valid icon images found for .ico" thrown in denoland/deno.

Source

Thrown at cli/tools/desktop.rs:5253

  cwd: &Path,
  entries: &[crate::args::IconSetEntry],
  ico_path: &Path,
) -> Result<(), deno_core::error::AnyError> {
  use std::io::Write;

  let mut images: Vec<(u32, Vec<u8>)> = Vec::new();
  for entry in entries {
    let src = cwd.join(&entry.path);
    if !src.exists() {
      log::warn!("Icon '{}' not found, skipping", src.display());
      continue;
    }
    let data = std::fs::read(&src)?;
    images.push((entry.size, data));
  }

  if images.is_empty() {
    deno_core::anyhow::bail!("No valid icon images found for .ico");
  }

  let count = images.len() as u16;
  // ICO header: 6 bytes
  // Each directory entry: 16 bytes
  let header_size = 6 + (count as u32) * 16;

  let mut buf = Vec::new();
  // ICO header
  buf.write_all(&0u16.to_le_bytes())?; // reserved
  buf.write_all(&1u16.to_le_bytes())?; // type: 1 = ICO
  buf.write_all(&count.to_le_bytes())?; // image count

  // Directory entries
  let mut data_offset = header_size;
  for (size, data) in &images {
    // Width/height: 0 means 256 in ICO format
    let dim = if *size >= 256 { 0u8 } else { *size as u8 };

View on GitHub (pinned to 89f33cbef2)

When it happens

Trigger: Thrown at cli/tools/desktop.rs:5253 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of denoland/deno@89f33cbef2 (2026-08-16). Data as JSON: /api/errors/dc9719696c6f4b93. Report an issue: GitHub.