slint-ui/slint · error

URL conversion can not fail here

Error message

URL conversion can not fail here

What it means

In `replace_x_as_y_with_newtype`, a source-file path is converted into an `lsp_types::Url` for a TextEdit. The conversion (`Url::from_file_path`) is expected to be infallible here because the path came from an already-valid document URL. Panicking means the stored file path is not a valid file:// URL-convertible path.

Solutions

1. Ensure the document was loaded from a real, absolute file path
2. Avoid renaming operations on virtual/untitled documents (non-file:// URIs)
3. Use `Url::from_file_path(...).ok()?` and skip the edit instead of panicking
4. Report the offending path to the Slint LSP maintainers if it is a normal absolute path

Example fix

// before
url_from_path(source_file.path()).expect("URL conversion can not fail here")

// after
match lsp_types::Url::from_file_path(source_file.path()) {
    Ok(url) => url,
    Err(_) => return None, // skip non-file documents
}

if !source_file.path().is_absolute() { return None; } // skip virtual/relative paths

fn to_url(p: &std::path::Path) -> Option<lsp_types::Url> { lsp_types::Url::from_file_path(p).ok() }

// if you own the caller
let Ok(url) = lsp_types::Url::from_file_path(path) else { return Ok(None) };

When it happens

Trigger: Renaming an `X as Y` type import when `source_file.path()` returns a path that cannot be converted to a URL (non-UTF-8 or non-absolute path, e.g. a virtual/synthetic document).

Common situations: LSP clients opening virtual in-memory documents with non-file schemes; network drives or Windows paths handled oddly; documents loaded from unusual sources.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• Identifier is in unknown document
• Child has no stdin
• Child has no stdout
• Callbacks were set up earlier
• Could not find executable name of the slint-lsp

AI-assisted analysis of slint-ui/slint@bb937076de (2026-09-16). Data as JSON: /api/errors/27f3fbc946130c95. Report an issue: GitHub.

Appendix: source

Thrown at internal/editor-preview/editing/rename_component.rs:199

        let start_position = util::text_size_to_lsp_position(
            source_file,
            x.text_range().start(),
            document_cache.format,
        );
        let end_position = util::text_size_to_lsp_position(
            source_file,
            y.text_range().end(),
            document_cache.format,
        );
        crate::editing::SingleTextEdit::from_path(
            document_cache,
            source_file.path(),
            lsp_types::TextEdit {
                range: lsp_types::Range::new(start_position, end_position),
                new_text: new_type.to_string(),
            },
        )
        .expect("URL conversion can not fail here")
    }

    let ti = query.parent_token_info();
    let source_file = type_name.source_file()?;

    if i_slint_compiler::parser::normalize_identifier(type_name.text()) == ti.name {
        if let Some(renamed_to) = renamed_to {
            if i_slint_compiler::parser::normalize_identifier(renamed_to.text())
                == i_slint_compiler::parser::normalize_identifier(new_type)
            {
                if query.has_parent_token_info() {
                    return query.update_parent_token_info(renamed_to);
                }

                // `Old as New` => `New`
                edits.push(replace_x_as_y_with_newtype(
                    document_cache,
                    source_file,

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