slint-ui/slint · error

Not a workspace, can not extract version info.

Error message

Not a workspace, can not extract version info.

What it means

CargoToml::workspace_version was called on a Cargo.toml that is not a workspace root (it has no [workspace] table), so no workspace.package.version can be extracted. The xtask license/version consistency check uses this to resolve inherited fields in member crates; calling it on a member manifest is an unsupported operation for that file kind.

Solutions

1. Call workspace_version only on manifests where is_workspace() is true; route member manifests through the package() path instead.
2. Run the xtask license/version check from the workspace root so the root Cargo.toml is used for version extraction.
3. If this fires unexpectedly, check the manifest for a [workspace] table; add one or fix the file-walk glob that picked the wrong manifest.
4. Refactor to a single resolver that checks is_workspace() once and returns the version from either workspace.package.version or package.version.

Example fix

// before
let version = cargo_toml.workspace_version()?;

// after
let version = if cargo_toml.is_workspace() {
    cargo_toml.workspace_version()?.to_owned()
} else {
    cargo_toml.package()?.get("version").and_then(|v| v.as_str()).unwrap_or_default().to_owned()
};

let version = if cargo_toml.is_workspace() {
    cargo_toml.workspace_version()?.to_owned()
} else {
    // fall back to the member's own package version or look up the root manifest
    cargo_toml.package()?.get("version")
        .and_then(|v| v.as_str()).unwrap_or("").to_owned()
};

fn is_workspace_root(doc: &toml_edit::DocumentMut) -> bool {
    doc.as_table().get("workspace").is_some()
}

match cargo_toml.workspace_version() {
    Ok(v) => use_version(v),
    Err(e) if e.to_string().contains("Not a workspace") => {
        // manifest is a member: resolve the version from the workspace root instead
        use_version(&resolve_root_version()?)
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: The check iterates manifests and passes a member crate's Cargo.toml (or any manifest without a [workspace] section) into workspace_version, which requires a workspace root with workspace.package.version.

Common situations: Running the xtask check against a single member crate directory instead of the repo root; a refactoring turned a former workspace root into a member; a vendored/example Cargo.toml without [workspace] is included in the manifest walk.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Invalid Cargo.toml -- cannot find workspace package section…
• Incorrect .workspace found: expected true, found false
• Invalid Cargo.toml -- cannot find package section
• Using workspace .workspace = true in workspace
• cargo failed

AI-assisted analysis of slint-ui/slint@3a7e700487 (2026-09-16). Data as JSON: /api/errors/2ac0f7ead29010a6. Report an issue: GitHub.

Appendix: source

Thrown at xtask/src/license_headers_check.rs:791

struct CargoToml {
    path: std::path::PathBuf,
    doc: toml_edit::DocumentMut,
    edited: bool,
}

impl CargoToml {
    fn new(path: &Path) -> Result<Self> {
        let source = &std::fs::read_to_string(path).context("Error reading file")?;
        Ok(Self { doc: source.parse()?, edited: false, path: path.to_path_buf() })
    }

    fn is_workspace(&self) -> bool {
        self.doc.as_table().get("workspace").is_some()
    }

    fn workspace_version(&self) -> Result<&str> {
        if !self.is_workspace() {
            Err(anyhow!("Not a workspace, can not extract version info."))
        } else {
            Ok(self
                .doc
                .as_table()
                .get("workspace")
                .unwrap()
                .get("package")
                .unwrap()
                .get("version")
                .unwrap()
                .as_str()
                .unwrap())
        }
    }

    fn package(&self) -> Result<&toml_edit::Table> {
        if self.is_workspace() {
            self.doc

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