--- title: "Error codes" description: "Every error code the Aontu engine can raise — 111 codes across 7 classes, with the class that decides your next move." source: "https://aontu.dev/errors/" --- # Error codes Every error Aontu raises carries a **code**, and every code has a **class**. The class says what kind of thing went wrong, which is what decides your next move. This is the registry itself, not a description of it: [`test/spec/errcodes.tsv`](https://github.com/aontu-lang/aontu/blob/main/test/spec/errcodes.tsv) is a shared contract both implementations execute, and each asserts set equality against — a code in one engine and not the file fails that engine's suite. Codes are append-only; renames are forbidden. Machine-readable: [`/errors.json`](https://aontu.dev/errors.json), or `/errors/.json` for one. ## `parse` 24 the text is not a document — fix the syntax at the site the frame points at - [`decimal_syntax`](https://aontu.dev/errors/decimal_syntax) - [`each_data`](https://aontu.dev/errors/each_data) - [`elided_value`](https://aontu.dev/errors/elided_value) - [`filter_data`](https://aontu.dev/errors/filter_data) - [`func_arity`](https://aontu.dev/errors/func_arity) - [`id_name`](https://aontu.dev/errors/id_name) - [`id_spread`](https://aontu.dev/errors/id_spread) - [`include_denied`](https://aontu.dev/errors/include_denied) - [`incomplete_expression`](https://aontu.dev/errors/incomplete_expression) - [`merge_conflict`](https://aontu.dev/errors/merge_conflict) - [`module_integrity`](https://aontu.dev/errors/module_integrity) - [`module_missing`](https://aontu.dev/errors/module_missing) - [`negative`](https://aontu.dev/errors/negative) - [`not_number`](https://aontu.dev/errors/not_number) - [`pack_data`](https://aontu.dev/errors/pack_data) - [`pack_key`](https://aontu.dev/errors/pack_key) - [`parse`](https://aontu.dev/errors/parse) - [`parse_bad_src`](https://aontu.dev/errors/parse_bad_src) - [`parse_unknown`](https://aontu.dev/errors/parse_unknown) - [`patch_assignment`](https://aontu.dev/errors/patch_assignment) - [`pipe_target`](https://aontu.dev/errors/pipe_target) - [`refer_address`](https://aontu.dev/errors/refer_address) - [`syntax`](https://aontu.dev/errors/syntax) - [`unify_no_src`](https://aontu.dev/errors/unify_no_src) ## `conflict` 45 two values cannot both hold — one of them is wrong: `aontu why` names both and where they were written - [`|:empty`](https://aontu.dev/errors/~7c~3aempty) - [`|:empty-dist`](https://aontu.dev/errors/~7c~3aempty-dist) - [`aggregate_data`](https://aontu.dev/errors/aggregate_data) - [`aggregate_empty`](https://aontu.dev/errors/aggregate_empty) - [`arg`](https://aontu.dev/errors/arg) - [`close`](https://aontu.dev/errors/close) - [`closed`](https://aontu.dev/errors/closed) - [`constraint`](https://aontu.dev/errors/constraint) - [`constraint_pattern`](https://aontu.dev/errors/constraint_pattern) - [`decimal_budget`](https://aontu.dev/errors/decimal_budget) - [`divide_by_zero`](https://aontu.dev/errors/divide_by_zero) - [`exact_float_mix`](https://aontu.dev/errors/exact_float_mix) - [`float_overflow`](https://aontu.dev/errors/float_overflow) - [`func`](https://aontu.dev/errors/func) - [`func:`](https://aontu.dev/errors/func~3a) family - [`id_conflict`](https://aontu.dev/errors/id_conflict) - [`inexact_divide`](https://aontu.dev/errors/inexact_divide) - [`inexact_integer_sum`](https://aontu.dev/errors/inexact_integer_sum) - [`invalid-arg`](https://aontu.dev/errors/invalid-arg) - [`key_level`](https://aontu.dev/errors/key_level) - [`list`](https://aontu.dev/errors/list) - [`literal_nil`](https://aontu.dev/errors/literal_nil) - [`lossy_integer_literal`](https://aontu.dev/errors/lossy_integer_literal) - [`make`](https://aontu.dev/errors/make) - [`map`](https://aontu.dev/errors/map) - [`match_none`](https://aontu.dev/errors/match_none) - [`must`](https://aontu.dev/errors/must) - [`nil_gen`](https://aontu.dev/errors/nil_gen) - [`no_first_arg`](https://aontu.dev/errors/no_first_arg) - [`no_scalar_unify`](https://aontu.dev/errors/no_scalar_unify) - [`not-scalar-type`](https://aontu.dev/errors/not-scalar-type) - [`op`](https://aontu.dev/errors/op) - [`op:`](https://aontu.dev/errors/op~3a) family - [`op[`](https://aontu.dev/errors/op~5b) family - [`operate`](https://aontu.dev/errors/operate) - [`pick_key`](https://aontu.dev/errors/pick_key) - [`place_pair`](https://aontu.dev/errors/place_pair) - [`relation_cycle`](https://aontu.dev/errors/relation_cycle) - [`relation_inverse_missing`](https://aontu.dev/errors/relation_inverse_missing) - [`relation_target_unmet`](https://aontu.dev/errors/relation_target_unmet) - [`resolve`](https://aontu.dev/errors/resolve) - [`scalar_kind`](https://aontu.dev/errors/scalar_kind) - [`scalar_value`](https://aontu.dev/errors/scalar_value) - [`scalar-type`](https://aontu.dev/errors/scalar-type) - [`unite`](https://aontu.dev/errors/unite) ## `incomplete` 10 nothing contradicts, but the value is not concrete — supply what is missing, or accept it with `--partial` - [`conjunct`](https://aontu.dev/errors/conjunct) - [`disjunct_no_gen`](https://aontu.dev/errors/disjunct_no_gen) - [`listval_no_gen`](https://aontu.dev/errors/listval_no_gen) - [`listval_required`](https://aontu.dev/errors/listval_required) - [`listval_spread_required`](https://aontu.dev/errors/listval_spread_required) - [`mapval_no_gen`](https://aontu.dev/errors/mapval_no_gen) - [`mapval_required`](https://aontu.dev/errors/mapval_required) - [`mapval_spread_required`](https://aontu.dev/errors/mapval_spread_required) - [`no_gen`](https://aontu.dev/errors/no_gen) - [`required_listelem`](https://aontu.dev/errors/required_listelem) ## `reference` 13 a path names nothing — check the spelling; `aontu get $ --keys` lists what is there - [`invalid_var_kind`](https://aontu.dev/errors/invalid_var_kind) - [`multisource_not_found`](https://aontu.dev/errors/multisource_not_found) - [`no_path`](https://aontu.dev/errors/no_path) - [`patch_ambiguous`](https://aontu.dev/errors/patch_ambiguous) - [`patch_not_editable`](https://aontu.dev/errors/patch_not_editable) - [`path_cycle`](https://aontu.dev/errors/path_cycle) - [`ref`](https://aontu.dev/errors/ref) - [`ref[`](https://aontu.dev/errors/ref~5b) family - [`refer_unresolved`](https://aontu.dev/errors/refer_unresolved) - [`unknown_function`](https://aontu.dev/errors/unknown_function) - [`unknown_var`](https://aontu.dev/errors/unknown_var) - [`var`](https://aontu.dev/errors/var) - [`var[`](https://aontu.dev/errors/var~5b) family ## `compat` 11 a change breaks an earlier version — that is `aontu subsume` / `aontu breaking` talking: widen the change or version it - [`compat_default_changed`](https://aontu.dev/errors/compat_default_changed) - [`compat_marks_changed`](https://aontu.dev/errors/compat_marks_changed) - [`compat_narrowed`](https://aontu.dev/errors/compat_narrowed) - [`compat_required_added`](https://aontu.dev/errors/compat_required_added) - [`deprecated`](https://aontu.dev/errors/deprecated) - [`pref_not_instance`](https://aontu.dev/errors/pref_not_instance) - [`sub_default_indeterminate`](https://aontu.dev/errors/sub_default_indeterminate) - [`sub_disjunct_distribution`](https://aontu.dev/errors/sub_disjunct_distribution) - [`sub_evaluate_only`](https://aontu.dev/errors/sub_evaluate_only) - [`sub_path_dependent_spread`](https://aontu.dev/errors/sub_path_dependent_spread) - [`sub_unresolved`](https://aontu.dev/errors/sub_unresolved) ## `budget` 4 evaluation hit a deterministic limit — usually a cycle; simplify, or raise the budget deliberately - [`budget_passes`](https://aontu.dev/errors/budget_passes) - [`max_depth`](https://aontu.dev/errors/max_depth) - [`module_depth`](https://aontu.dev/errors/module_depth) - [`unify_cycle`](https://aontu.dev/errors/unify_cycle) ## `internal` 4 the engine surprised itself — a bug worth reporting - [`internal`](https://aontu.dev/errors/internal) - [`patch_span_mismatch`](https://aontu.dev/errors/patch_span_mismatch) - [`unify_no_res`](https://aontu.dev/errors/unify_no_res) - [`unknown_op`](https://aontu.dev/errors/unknown_op)