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

{manifest_key_name} `{}` does not appear to exist{}.

Error message

{manifest_key_name} `{}` does not appear to exist{}.
                Please update the {manifest_key_name} setting in the manifest at `{}`.

What it means

During packaging, Cargo validates manifest path fields (`license-file` and `readme`) by joining them to the package root and checking is_file(). If the referenced file is missing, error_on_nonexistent_file pushes a message (naming the manifest key, the path, and the manifest location) into invalid_manifest_field; once all checks finish, if that buffer is non-empty it is thrown as a single aggregated anyhow error at cargo_package/mod.rs:621.

Source

Thrown at src/ops/cargo_package/mod.rs:621

                &pkg,
                &license_path,
                "license-file",
                &mut invalid_manifest_field,
            );
        }
    }
    if let Some(readme) = &pkg.manifest().metadata().readme {
        let readme_path = Path::new(readme);
        let abs_file_path = paths::normalize_path(&pkg.root().join(readme_path));
        if abs_file_path.is_file() {
            check_for_file_and_add("readme", readme_path, abs_file_path, pkg, &mut result, ws)?;
        } else {
            error_on_nonexistent_file(&pkg, &readme_path, "readme", &mut invalid_manifest_field);
        }
    }

    if !invalid_manifest_field.is_empty() {
        return Err(anyhow::anyhow!(invalid_manifest_field.join("\n")));
    }

    for t in pkg
        .manifest()
        .targets()
        .iter()
        .filter(|t| t.is_custom_build())
    {
        if let Some(custom_build_path) = t.src_path().path() {
            let abs_custom_build_path = paths::normalize_path(&pkg.root().join(custom_build_path));
            if !abs_custom_build_path.is_file() || !abs_custom_build_path.starts_with(pkg.root()) {
                error_custom_build_file_not_in_package(pkg, &abs_custom_build_path, t)?;
            }
        }
    }

    result.sort_unstable_by(|a, b| a.rel_path.cmp(&b.rel_path));

View on GitHub (pinned to 0e07a15537)

Solutions

1. Create or restore the referenced file (e.g. `touch README.md` or restore LICENSE)
2. Update Cargo.toml so `license-file`/`readme` points to the correct existing path
3. Remove the field from Cargo.toml entirely if the file is not needed
4. Ensure the path is relative to the package root and the file is committed (not gitignored)

Example fix

# before
# Cargo.toml: readme = "README.md"  (file missing)
cargo package   # -> error
# after (option A): create the file
echo '# mycrate' > README.md
# after (option B): fix the path
# readme = "docs/README.md"
# after (option C): drop the field
# (remove the readme = line)

use std::path::{Path, PathBuf};
fn validate_manifest_paths(root: &Path, fields: &[(&str, &str)]) -> Result<(), String> {
    for (key, val) in fields {
        let abs = root.join(val);
        if !abs.is_file() {
            return Err(format!("{key} `{val}` does not exist at {}", abs.display()));
        }
    }
    Ok(())
}

validate_manifest_paths(root, &[("readme", readme), ("license-file", license)])?;

import { existsSync } from 'fs';
import { join } from 'path';
function manifestPathsExist(root: string, fields: Record<string,string>): boolean {
  return Object.entries(fields).every(([_, rel]) => existsSync(join(root, rel)));
}

When it happens

Trigger: `cargo package` with `license-file = "LICENSE"` when no LICENSE file exists, or `readme = "README.md"` after the README was deleted/renamed. Also fires if the path is relative but resolves outside the package.

Common situations: Deleted the README but left `readme = ` in Cargo.toml; renamed LICENSE-MIT to LICENSE without updating the manifest; path typos; CI packaging a sparse checkout that omitted the license/readme; relative paths that escape the package root.

Related errors

• could not compile due to {error_count} previous target resol
• {}This may cause issue during packaging, as modules resoluti
• `resolver` setting `{}` is not valid, valid options are "1",
• '{}' is not a valid artifact specifier
• Cannot specify both 'bin' and 'bin:<name>' binary artifacts,

AI-assisted analysis of rust-lang/cargo@0e07a15537 (2026-08-06). Data as JSON: /data/errors/a57572a1b715dcfc.json. Report an issue: GitHub.