slint-ui/slint · error · CompileError

Could not compile

Error message

Could not compile {path}

What it means

Raised by _load_file when the Slint compiler produced error-level diagnostics while compiling the given .slint file. The CompileError carries the full diagnostics list, so the actual parse/type errors are available on the exception.

Solutions

  1. Catch slint.CompileError and inspect e.diagnostics to see each error's line/column and message.
  2. Fix the reported .slint errors (syntax, unknown identifiers, type errors) in the referenced file.
  3. Check import paths and that all referenced components/globals exist and are exported.
  4. Validate the file with the slint-viewer or an editor with the Slint LSP before loading it at runtime.

Example fix

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

# after
try:
    module = slint.load_file("app.slint")
except slint.CompileError as e:
    for d in e.diagnostics:
        print(d.filename, d.line, d.column, d.message)
Defensive patterns

Strategy: try-catch

Validate before calling

from pathlib import Path
assert Path("app.slint").exists(), "missing .slint file"

Try / catch

try:
    module = slint.load_file("app.slint")
except slint.CompileError as e:
    for d in e.diagnostics:
        print(f"{d.filename}:{d.line}:{d.column}: {d.message}")
    raise

Prevention

When it happens

Trigger: Calling slint.load_file(path) (directly or via load/compile APIs) on a .slint file containing syntax errors, unknown elements/properties, type errors, or missing imports.

Common situations: Typos in .slint markup; using features not enabled in the compiler version; referencing components or globals that don't exist; broken paths in imports; editing .slint files by hand without an LSP.

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

AI-assisted analysis of slint-ui/slint@bb937076de (2026-09-16). Data as JSON: /api/errors/8b717858e30003d1. Report an issue: GitHub.

Appendix: 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 bb937076de)