denoland/deno · error

No lockfile found. Run `deno install` first.

Error message

No lockfile found. Run `deno install` first.

What it means

`deno why` explains why a package is in the dependency graph by walking the lockfile (deno.lock). It hard-requires a lockfile; without one there are no resolutions to explain, hence the pointer to `deno install`.

Source

Thrown at cli/tools/pm/why.rs:65

/// The string portion is the lockfile's key:
/// - npm: e.g. "express@4.22.1" or "react-dom@18.2.0_react@18.2.0"
/// - jsr: e.g. "@std/async@1.2.0"
type PkgId = (PackageKind, String);

fn display_base(id: &PkgId) -> &str {
  match id.0 {
    PackageKind::Npm => strip_peer_suffix(&id.1),
    PackageKind::Jsr => &id.1,
  }
}

pub async fn why(
  flags: Arc<Flags>,
  why_flags: WhyFlags,
) -> Result<(), AnyError> {
  let factory = CliFactory::from_flags(flags);
  let lockfile = factory.maybe_lockfile().await?.cloned().ok_or_else(|| {
    deno_core::anyhow::anyhow!("No lockfile found. Run `deno install` first.")
  })?;

  // Workspace-declared root dependency requirements (from deno.json `imports`,
  // `scopes`, `jsxImportSource`, etc., and from package.json
  // `dependencies`/`devDependencies`). These are matched against the lockfile's
  // `specifiers` map to decide which entries are user-imported roots vs.
  // transitive resolutions that the lockfile also stores under `specifiers`
  // (as JSR does for every dep req).
  let workspace = factory.cli_options()?.workspace();
  let mut root_reqs: HashSet<JsrDepPackageReq> = HashSet::new();
  for deno_json in workspace.deno_jsons() {
    root_reqs.extend(deno_json.dependencies(workspace.catalogs()));
  }
  for pkg_json in workspace.package_jsons() {
    let deps = pkg_json.resolve_local_package_json_deps();
    for dep in deps
      .dependencies
      .values()

View on GitHub (pinned to 89f33cbef2)

Solutions

1. Run `deno install` to generate deno.lock, then retry deno why
2. Make sure you are in the workspace directory the lockfile belongs to
3. Remove --no-lock / re-enable the lockfile if you want deno why to work
4. Restore deno.lock from version control if it was deleted

Example fix

# before
$ deno why chalk
Error: No lockfile found. Run `deno install` first.
# after
$ deno install && deno why chalk

test -f deno.lock || { echo 'no lockfile — run deno install first' >&2; exit 2; }
deno why "$1"

When it happens

Trigger: `deno why <pkg>` in a project that never ran `deno install`, with deno.lock deleted, or with the lockfile disabled (--no-lock or lockfile disabled in config).

Common situations: Fresh clones where install was skipped; CI jobs disabling the lockfile for speed; lockfiles gitignored or removed during cleanup.

Related errors

• A deno.json file could not be found or created
• Could not load or create deno.json
• Could not determine directory of '{}'
• Could not resolve package req '{}' from graph because it was

AI-assisted analysis of denoland/deno@89f33cbef2 (2026-08-16). Data as JSON: /api/errors/433368dfbcc44c71. Report an issue: GitHub.