Cargo "failed to get X as a dependency" in CI

By Daniel Zoghalchali·Latchkey

failed to get X as a dependency of package Y is Cargo’s wrapper message. The real cause - an index update failure, a download error, or an unreachable git source - is in the Caused by: lines beneath it.

What this error means

cargo prints failed to get <crate> as a dependency of package <yours> followed by one or more Caused by: lines. The wrapper is generic; the actual failure (network, auth, missing rev) is in the chain below.

error: failed to get `anyhow` as a dependency of package `app v0.1.0`

Caused by:
  failed to load source for dependency `anyhow`
Caused by:
  Unable to update https://github.com/dtolnay/anyhow
Caused by:
  failed to clone into: /home/runner/.cargo/git/db/anyhow-...

Common causes

A git or path source could not be loaded

For a git = "..." dependency, Cargo could not clone or update the repo - a bad URL, a deleted branch/rev, or missing credentials for a private repo.

An underlying index or download failure

The wrapper often sits on top of a failed to update registry or failed to download cause - a transient network issue fetching the crate.

How to fix it

Read the full Caused-by chain

1. Scroll to the deepest Caused by: line - that is the real error.
2. For a git source, verify the URL, branch, tag, or rev exists and is reachable.
3. For a private git repo, configure credentials (a token or SSH key) for the runner.

Pin a git dependency to a real rev

A dropped branch or moved tag breaks the clone. Pin an existing commit so it stays resolvable.

[dependencies]
anyhow = { git = "https://github.com/dtolnay/anyhow", rev = "abc1234" }

How to prevent it

• Pin git dependencies to a commit or tag that won’t disappear.
• Configure credentials for private git/registry sources in CI.
• Cache ~/.cargo/git so clones don’t repeat on every run.

Frequently asked questions

Related guides

References

• The Cargo Book
• GitHub Actions documentation