cross-rs/cross · error

unable to find provided nix-store directory

Error message

unable to find provided nix-store directory {store:?}

What it means

In the Nix cross-compilation path, `assemble` accepts a user-supplied nix-store directory. If one was explicitly provided (via config/flag) but does not exist on disk, it fails rather than silently falling back to the default store path.

Solutions

1. Verify the configured nix-store path exists: `ls /nix/store` or the custom path; fix typos.
2. Remove the custom nix-store override so the default `/nix/store` is used when it exists.
3. Ensure you're running inside the Nix environment (nix-shell/nix develop) where the store is mounted.

Example fix

// before
let opts = Options { nix_store: Some("/nx/store".into()), .. } // typo
// after
let opts = Options { nix_store: Some("/nix/store".into()), .. }

if let Some(store) = &opts.nix_store {
    if !store.exists() {
        return Err(format!("nix-store path {} does not exist", store.display()));
    }
}

fn valid_nix_store(p: &std::path::Path) -> bool { p.is_dir() }

When it happens

Trigger: Calling `assemble` with `nix_store = Some(path)` where `path.exists()` is false — e.g. a custom store path pointing to a non-existent or typo'd directory.

Common situations: Nix store mounted at a non-default location that was moved/deleted, running outside the Nix environment where the configured store path doesn't exist, typos in config, or chroot/container contexts lacking the mount.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• failed to serialize CrossToml as object
• unix paths cannot handle windows prefix
• unsupported rust target for file
• invalid linux version, got
• workspace_root can't end in `..`

AI-assisted analysis of cross-rs/cross@8c1a8aa4b6 (2026-09-13). Data as JSON: /api/errors/16152f09e1cd2b12. Report an issue: GitHub.

Appendix: source

Thrown at src/docker/shared.rs:293

        if let Some(ref nix_store) = nix_store {
            file::create_dir_all(nix_store)?;
        }

        // get our mount paths prior to canonicalizing them
        let cargo_mount_path = cargo.as_posix_absolute()?;

        // now that we know the paths exist, canonicalize them. this avoids creating
        // directories after failed canonicalization into a shared directory.
        let cargo = file::canonicalize(&cargo)?;

        let default_nix_store = PathBuf::from("/nix/store");
        let nix_store = match nix_store {
            Some(store) if store.exists() => {
                let path = file::canonicalize(store)?;
                Some(path)
            }
            Some(store) => {
                eyre::bail!("unable to find provided nix-store directory {store:?}");
            }
            None if cfg!(target_os = "linux") && default_nix_store.exists() => {
                Some(default_nix_store)
            }
            None => None,
        };

        let cargo = mount_finder.find_mount_path(cargo);

        // canonicalize these once to avoid syscalls
        let sysroot_mount_path = toolchain.get_sysroot().as_posix_absolute()?;

        Ok(ToolchainDirectories {
            cargo,
            nix_store,
            toolchain,
            cargo_mount_path,
            sysroot_mount_path,

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