denoland/deno · error · anyhow::Error

Invalid YAML

Error message

Invalid YAML: {e}

What it means

Deno reads pnpm-workspace.yaml to support pnpm-style workspaces and catalogs, parsing it with the same yaml_parser CST already used by `deno fmt` (parse_pnpm_workspace, cli/util/pnpm_workspace.rs:249-252). Any YAML syntax error — bad indentation, tabs, unclosed quotes or flow collections, duplicate keys — aborts loading with "Invalid YAML: {parser error}", including the position the parser reported.

Solutions

1. Fix the reported position: the {e} in the message carries the parser's line/column detail.
2. Validate the file before retrying: `pnpm install` (pnpm's own parser) or a YAML linter / yq pnpm-workspace.yaml.
3. Check for tabs (YAML requires spaces), smart quotes, and duplicate top-level keys.

Example fix

# pnpm-workspace.yaml — before
packages:
  - 'apps/*'
catalog:
  react: ^18.2.0
    lodash: ^4.17.21   # wrong indentation

# after
catalog:
  react: ^18.2.0
  lodash: ^4.17.21

# Validate pnpm-workspace.yaml before running deno in the workspace
if command -v pnpm >/dev/null; then pnpm install --lockfile-only >/dev/null \
  || { echo 'pnpm-workspace.yaml is invalid'; exit 1; }; fi
deno task build

When it happens

Trigger: Any workspace-root pnpm-workspace.yaml that fails to parse, hit as soon as Deno loads config (deno install/task/run/check) in that directory; hand-edited catalog blocks with misaligned indentation are the classic case.

Common situations: Merging catalog entries by hand; smart quotes or tabs pasted from chat/docs; renaming keys and breaking list syntax; YAML files edited by tools that emit single quotes oddly.

Related errors

• A deno.json file could not be found or created
• Bench attempted to exit with exit code
• workspace root is not a local directory
• Both 'cert' and 'key' must be provided to enable HTTPS
• Cannot generate declarations for files with different…

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/fd201cb16e3e77e8. Report an issue: GitHub.

Appendix: source

Thrown at cli/util/pnpm_workspace.rs:252

}

fn string_map_to_value(map: &IndexMap<String, String>) -> CstInputValue {
  CstInputValue::Object(
    map
      .iter()
      .map(|(k, v)| (k.clone(), CstInputValue::String(v.clone())))
      .collect(),
  )
}

// ===========================================================================
// pnpm-workspace.yaml parsing (via the yaml_parser CST already used by
// `deno fmt`, so no new YAML dependency is introduced).
// ===========================================================================

fn parse_pnpm_workspace(text: &str) -> Result<PnpmWorkspace, AnyError> {
  let tree = yaml_parser::parse(text)
    .map_err(|e| deno_core::anyhow::anyhow!("Invalid YAML: {e}"))?;
  let Some(root) = Root::cast(tree) else {
    return Ok(PnpmWorkspace::default());
  };
  let Some(block_map) = root
    .documents()
    .next()
    .and_then(|doc: Document| doc.block())
    .and_then(|block| block.block_map())
  else {
    return Ok(PnpmWorkspace::default());
  };

  let mut result = PnpmWorkspace::default();
  for entry in block_map.entries() {
    let Some(key) = entry.key().map(|k| k.syntax().clone()) else {
      continue;
    };
    let Some(key_name) = scalar_text(&key) else {

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