slint-ui/slint · error · CompileError

Could not compile {path}

Error message

Could not compile {path}

What it means

slint.load_file()/load_str() compile .slint through the native interpreter and collect diagnostics; warnings are logged (unless quiet=True) and any diagnostic of level Error causes slint.CompileError to be raised with message 'Could not compile <path>'. Each PyDiagnostic in error.diagnostics (also attached as exception notes) carries file, line, column and message pinpointing the failure.

Source

Thrown at api/python/slint/slint/__init__.py:349

    if translation_domain is not None:
        compiler.translation_domain = translation_domain

    result = compiler.build_from_path(Path(path))

    diagnostics = result.diagnostics
    if diagnostics:
        if not quiet:
            for diag in diagnostics:
                if diag.level == native.DiagnosticLevel.Warning:
                    _logger.warning(diag)
                if diag.level == native.DiagnosticLevel.Note:
                    _logger.debug(diag)

        errors = [
            diag for diag in diagnostics if diag.level == native.DiagnosticLevel.Error
        ]
        if errors:
            raise CompileError(f"Could not compile {path}", diagnostics)

    module = types.SimpleNamespace()
    for comp_name in result.component_names:
        wrapper_class = _build_class(result.component(comp_name))

        setattr(module, comp_name, wrapper_class)

    structs, enums = result.structs_and_enums

    for name, struct_prototype in structs.items():
        name = _normalize_prop(name)
        struct_wrapper = _build_struct(name, struct_prototype)
        setattr(module, name, struct_wrapper)

    for name, enum_class in enums.items():
        name = _normalize_prop(name)
        setattr(module, name, enum_class)

View on GitHub (pinned to a9ea814a58)

Solutions

1. Catch slint.CompileError and print each diagnostic (its str() includes file:line:column and message) to find the exact markup problem.
2. Fix the reported locations in the .slint source.
3. Ensure imports resolve: run from the right working directory or adjust include paths.
4. Validate markup beforehand with the Slint LSP / VS Code extension or slint-viewer.
5. Reinstall/upgrade the slint Python package to match the markup's feature level.

Example fix

# before
import slint
module = slint.load_file("app.slint")  # raises CompileError

# after
import slint
try:
    module = slint.load_file("app.slint")
except slint.CompileError as e:
    for diag in e.diagnostics:
        print(diag)  # [file:line:col] message
    raise SystemExit(1)

def is_compile_error(e: BaseException) -> bool:
    return isinstance(e, slint.CompileError)

try:
    module = slint.load_file("app.slint")
except slint.CompileError as e:
    for diag in e.diagnostics:
        print(diag)  # [file:line:col] message
    raise SystemExit(1)

When it happens

Trigger: Calling slint.load_file("app.slint") (or load_str) on markup with syntax errors, unknown elements/properties, type mismatches, or unresolvable imports; also when an imported file is missing from the include paths.

Common situations: Typos in .slint, renamed APIs after a slint-python upgrade, wrong relative import paths, styles not installed, or loading a file written for a newer Slint version.

Related errors

• Could not compile ${filePath}
• Callback '{name}' in global '{global_name}' cannot be used w
• Callback '{name}' in global '{global_name}' cannot be used w
• Callback '{name}' cannot be used with a callback decorator f
• Callback '{name}' cannot be used with a callback decorator f

AI-assisted analysis of slint-ui/slint@a9ea814a58 (2026-08-16). Data as JSON: /api/errors/8b717858e30003d1. Report an issue: GitHub.