slint-ui/slint · error

dev-dependencies cannot be from the workspace because…

Error message

dev-dependencies cannot be from the workspace because version must be empty {dep_name}

What it means

dev-dependencies on slint/i-slint packages must not use `workspace = true` inheritance because the check requires dev-dependency declarations to carry an explicit (empty-of-workspace) version field; workspace-inherited dev-dependencies lose the explicit version the publish pipeline needs. check_dependencies rejects `CargoDependency::Workspace` for any slint/i-slint entry under `[dev-dependencies]`.

Solutions

1. Replace workspace inheritance with an explicit path + version entry, e.g. `slint = { version = "=1.8.0", path = "../../api/rs/slint" }` under `[dev-dependencies]`.
2. If the dependency is only used by tests, consider pointing at the test-driver or interpreter crate with an explicit version instead.
3. Check the workspace root `[workspace.dependencies]` convention for how slint dev-dependencies are expected to be spelled.

Example fix

// before
[dev-dependencies]
slint = { workspace = true }
// after
[dev-dependencies]
slint = { version = "=1.8.0", path = "../../api/rs/slint" }

const devDeps = toml.parse(fs.readFileSync('Cargo.toml'))['dev-dependencies'] ?? {};
for (const [n, d] of Object.entries(devDeps)) {
  if ((n.startsWith('slint') || n.startsWith('i-slint')) && d?.workspace) {
    throw new Error(`${n} dev-dependency must not use workspace inheritance`);
  }
}

When it happens

Trigger: Writing `slint = { workspace = true }` under `[dev-dependencies]` in a crate's Cargo.toml and running the xtask Cargo.toml/license checks; converting a normal dependency to workspace inheritance without noticing the dev-dependency rule.

Common situations: Refactoring many Cargo.toml files to workspace dependency inheritance and applying it uniformly, including dev-dependencies; an IDE or cargo-add auto-inserting workspace inheritance.

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

• cargo failed
• Incorrect . Found expected
• Invalid Cargo.toml -- cannot find workspace package section…
• Missing description field
• Missing field

AI-assisted analysis of slint-ui/slint@3a7e700487 (2026-09-16). Data as JSON: /api/errors/a59e14cf07cdc5ee. Report an issue: GitHub.

Appendix: source

Thrown at xtask/src/license_headers_check.rs:1192

                            ));
                        }
                        if version != &expected_version {
                            return Err(anyhow!(
                                "Version \"{}\" must be specified for dependency {}",
                                expected_version,
                                dep_name
                            ));
                        }
                    }
                }
            }
        }

        for (dep_name, dep) in doc.dependencies("dev-dependencies").iter() {
            if dep_name.starts_with("slint") || dep_name.starts_with("i-slint") {
                match dep {
                    CargoDependency::Workspace => {
                        return Err(anyhow!(
                            "dev-dependencies cannot be from the workspace because version must be empty {dep_name}"
                        ));
                    }
                    CargoDependency::Full { path, version } => {
                        if path.is_empty() {
                            return Err(anyhow!(
                                "slint package '{}' outside of the repository?",
                                dep_name
                            ));
                        }
                        if !version.is_empty() {
                            return Err(anyhow!(
                                "dev-dependencies version must be empty for dependency {dep_name}"
                            ));
                        }
                    }
                }
            }

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