slint-ui/slint · error

unexpected header. expected

Error message

unexpected header.
expected: {}
found: {}

What it means

check_file_tags throws this when a file HAS a license tag but its content does not match the expected Slint header (EXPECTED_HEADER). The error shows the expected and found header text for comparison.

Solutions

1. Run `cargo xtask check --fix` to replace the wrong header with EXPECTED_HEADER
2. Manually replace the file's header with the exact expected text shown in the error message
3. Compare the 'found:' output against the expected text to see what differs (usually SPDX id or copyright line)

Example fix

// before
// SPDX-License-Identifier: MIT
// after
// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-commercial

let src = std::fs::read_to_string(path)?;
let expected = "// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-commercial";
if !src.contains(expected) {
    panic!("{path}: wrong SPDX header, expected {expected}");
}

fn header_matches(src: &str, expected: &str) -> bool {
    src.lines().take(5).any(|l| l.trim() == expected)
}

When it happens

Trigger: A file whose header differs in copyright line, SPDX identifier, or formatting (e.g. an older header variant, wrong year range, or `// SPDX-License-Identifier: MIT` instead of the required expression), checked without --fix.

Common situations: License policy change leaving stale headers; copying a header from another project; reformatting tools mangling the header; an import from a fork.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Missing tag
• License ` ` of crate is not in the accepted list
• Missing LICENSES directory for published crate
• No license file found in root LICENSES/ for SPDX id
• Encountered one or multiple errors. See above for details.

AI-assisted analysis of slint-ui/slint@3a7e700487 (2026-09-16). Data as JSON: /api/errors/4d0b3eb4a4232dd7. Report an issue: GitHub.

Appendix: source

Thrown at xtask/src/license_headers_check.rs:991

        let source = SourceFileWithTags::new(source, style);

        if !source.has_tag() {
            if self.fix_it {
                eprintln!("Fixing up {path:?} as instructed. It's missing a license header.");
                let source = source.replace_tag(&EXPECTED_HEADER, license);
                std::fs::write(path, source).context("Error writing source")
            } else {
                Err(anyhow!("Missing tag"))
            }
        } else if source.tag_matches(&EXPECTED_HEADER, license) {
            Ok(())
        } else if self.fix_it {
            eprintln!("Fixing up {path:?} as instructed. It has a wrong license header.");
            let source = source.replace_tag(&EXPECTED_HEADER, license);
            std::fs::write(path, source).context("Error writing new source")
        } else {
            Err(anyhow!(
                "unexpected header.\nexpected: {}\nfound: {}",
                EXPECTED_HEADER.to_string(style, license),
                source.found_tag()
            ))
        }
    }

    fn check_cargo_toml(&self, path: &Path, license: &str) -> Result<()> {
        let mut doc = CargoToml::new(path)?;

        if doc.is_workspace() {
            let mut wv = self.workspace_version.borrow_mut();
            if (*wv).is_empty() {
                *wv = doc.workspace_version()?.to_string();
            }
            let expected_version = wv.clone();

            // Check the workspace.dependencies:

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