rust-lang/cargo · error · anyhow::Error

several `[patch]` entries resolving to same version `{} v{}`

Error message

several `[patch]` entries resolving to same version `{} v{}`
help: check `{}` patch definitions for `{}` in {}

What it means

Error "several `[patch]` entries resolving to same version `{} v{}` help: check `{}` patch definitions for `{}` in {}" thrown in rust-lang/cargo.

Source

Thrown at src/workspace/registry.rs:459

                    url,
                    orig_patch.loc
                ));
            }
            Ok(summary)
        }).collect::<CargoResult<Vec<_>>>()?;

        let mut name_and_version = HashSet::default();
        for summary in unlocked_summaries.iter() {
            let name = summary.package_id().name();
            let version = summary.package_id().version();
            if !name_and_version.insert((name, version)) {
                let duplicate_locations = patch_deps
                    .iter()
                    .filter(|&p| p.0.dep.package_name() == name)
                    .map(|p| format!("`{}`", p.0.loc))
                    .unique()
                    .join(", ");
                return Err(anyhow::anyhow!(
                    "several `[patch]` entries resolving to same version `{} v{}`\n\
                    help: check `{}` patch definitions for `{}` in {}",
                    name,
                    version,
                    name,
                    url,
                    duplicate_locations
                ));
            }
        }

        // Calculate a list of all patches available for this source.
        let mut ids = Vec::new();
        for (summary, (_, lock)) in unlocked_summaries.iter().zip(patch_deps) {
            ids.push(summary.package_id());
            // This is subtle where the list of `ids` for a canonical URL is
            // extend with possibly two ids per summary. This is done to handle
            // the transition from the v2->v3 lock file format where in v2

View on GitHub (pinned to 0e07a15537)

Solutions

1. Keep only one `[patch]` entry resolving to that version; remove or narrow the duplicates.
2. Make patch definitions more specific so they do not overlap.

When it happens

Trigger: Thrown at src/workspace/registry.rs:459 when the library encounters an invalid state.

Common situations: Occurs when multiple `[patch]` entries resolve to the same package version. Consolidate or disambiguate the patch entries so only one patch resolves to that version.

AI-assisted analysis of rust-lang/cargo@0e07a15537 (2026-08-06). Data as JSON: /data/errors/dccb8058fd89f6bb.json. Report an issue: GitHub.