slint-ui/slint · error

Invalid Cargo.toml -- cannot find workspace package section…

Error message

Invalid Cargo.toml -- cannot find workspace package section in workspace file

What it means

CargoToml::package() found a [workspace] table but no [workspace.package] table (or it is not a TOML table) in the workspace root manifest, so the workspace-level package settings used for inheritance cannot be read. The manifest is therefore considered invalid for the purposes of the xtask license/version consistency check.

Solutions

1. Add a [workspace.package] section with the shared fields (version, license, etc.) to the workspace root Cargo.toml.
2. Verify the [workspace] table parses as a table and contains package = { ... }; fix any malformed TOML.
3. If this manifest is a virtual workspace with no intended shared package config, exclude it from this check or handle it before calling package().
4. Ensure the check runs against the correct manifest path; a member manifest misdetected as a root would trigger this.

Example fix

// before: workspace root missing inheritance metadata
[workspace]
members = ["crates/foo"]

// after
[workspace]
members = ["crates/foo"]

[workspace.package]
version = "1.0.0"
license = "GPL-3.0-only OR MIT"

fn has_workspace_package(doc: &toml_edit::DocumentMut) -> bool {
    doc.as_table().get("workspace")
        .and_then(|w| w.as_table())
        .and_then(|w| w.get("package"))
        .and_then(|p| p.as_table())
        .is_some()
}

fn workspace_package_table(doc: &toml_edit::DocumentMut) -> Option<&toml_edit::Table> {
    doc.as_table().get("workspace")?.as_table()?.get("package")?.as_table()
}

match cargo_toml.package() {
    Ok(pkg) => check_fields(pkg),
    Err(e) if e.to_string().contains("workspace package section") => {
        anyhow::bail!("{}: add a [workspace.package] section with shared version/license", cargo_toml.path.display())
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: package() is called (from check_and_fix_package_string_field or published) on a workspace root Cargo.toml that lacks a workspace.package section, or whose [workspace] table has no parseable package sub-table.

Common situations: A workspace root created without workspace.package metadata (no shared version/license fields); a malformed edit removed [workspace.package]; a manifest with an empty [workspace] table (e.g. a virtual workspace without package inheritance config) is checked.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Incorrect .workspace found: expected true, found false
• Invalid Cargo.toml -- cannot find package section
• Not a workspace, can not extract version info.
• Using workspace .workspace = true in workspace
• cargo failed

AI-assisted analysis of slint-ui/slint@3a7e700487 (2026-09-16). Data as JSON: /api/errors/9aa14d79e03a1e48. Report an issue: GitHub.

Appendix: source

Thrown at xtask/src/license_headers_check.rs:815

                .unwrap()
                .get("package")
                .unwrap()
                .get("version")
                .unwrap()
                .as_str()
                .unwrap())
        }
    }

    fn package(&self) -> Result<&toml_edit::Table> {
        if self.is_workspace() {
            self.doc
                .as_table()
                .get("workspace")
                .and_then(|w| w.as_table())
                .and_then(|w| w.get("package"))
                .and_then(|p| p.as_table())
                .ok_or_else(|| anyhow!("Invalid Cargo.toml -- cannot find workspace package section in workspace file"))
        } else {
            self.doc
                .as_table()
                .get("package")
                .and_then(|p| p.as_table())
                .ok_or_else(|| anyhow!("Invalid Cargo.toml -- cannot find package section"))
        }
    }

    fn dependencies(&self, dep_type: &str) -> Vec<(String, CargoDependency)> {
        let table = if self.is_workspace() {
            self.doc
                .as_table()
                .get("workspace")
                .and_then(|w| w.as_table())
                .and_then(|w| w.get(dep_type))
                .and_then(|d| d.as_table())
        } else {

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