Humanizr/Humanizer · error · InvalidOperationException

Unexpected east-asian scale builder.

Error message

Unexpected east-asian scale builder.

What it means

The builder name 'east-asian-scale-array' is explicitly registered as a throw in the builder switch. This is an intentional guard: east-asian scale words are handled exclusively by the AddEngineMetricScaleWords path for the 'east-asian-grouped' engine, not through the generic builder pipeline. If a contract member references this builder, it signals a misconfiguration.

Source

Thrown at src/Humanizer.SourceGenerators/Generators/ProfileCatalogs/NumberToWordsEngineContractFactory.cs:510

                ? root
                : EngineContractUtilities.GetRequiredElement(root, member.SourcePath);

            // Builders exist for repeated structured rows such as scale tables, suffix rules, and
            // gender-ending records. Keeping these explicit makes the generated output easier to
            // audit than trying to encode a second generic mini-language for nested collections.
            return member.Builder switch
            {
                "harmony-ordinal-scale-array" => CreateHarmonyOrdinalScaleArrayExpression(builderRoot),
                "billion-strategy-cardinal-scale-array" => CreateBillionStrategyCardinalScaleArrayExpression(builderRoot),
                "contracted-one-scale-array" => CreateContractedOneScaleArrayExpression(builderRoot),
                "linking-scale-array" => CreateLinkingScaleArrayExpression(builderRoot),
                "linking-suffix-rule-array" => CreateLinkingSuffixRuleArrayExpression(builderRoot),
                "agglutinative-ordinal-scale-array" => CreateAgglutinativeOrdinalScaleArrayExpression(builderRoot),
                "contextual-decimal-scale-array" => CreateContextualDecimalScaleArrayExpression(builderRoot),
                "conjunctional-scale-array" => CreateConjunctionalScaleArrayExpression(builderRoot),
                "joined-scale-array" => CreateJoinedScaleArrayExpression(builderRoot),
                "west-slavic-scale-forms" => CreateWestSlavicScaleFormsExpression(builderRoot),
                "east-asian-scale-array" => throw new InvalidOperationException("Unexpected east-asian scale builder."),
                "east-slavic-scale-array" => CreateEastSlavicScaleArrayExpression(builderRoot),
                "east-slavic-gender-ending" => CreateEastSlavicGenderEndingExpression(builderRoot),
                "pluralized-scale-array" => CreatePluralizedScaleArrayExpression(builderRoot),
                "ordinal-prefix-scale-array" => CreateOrdinalPrefixScaleArrayExpression(builderRoot),
                "inverted-tens-scale-array" => CreateInvertedTensScaleArrayExpression(builderRoot),
                "indian-scale-form-array" => CreateIndianScaleFormArrayExpression(builderRoot),
                "south-slavic-scale-array" => CreateSouthSlavicScaleArrayExpression(builderRoot),
                "scale-leading-compound-scale-array" => CreateScaleLeadingCompoundScaleArrayExpression(builderRoot),
                "scandinavian-scale-array" => CreateScaleStrategyScaleArrayExpression(builderRoot),
                "unit-leading-compound-scale-array" => CreateUnitLeadingCompoundScaleArrayExpression(builderRoot),
                "conjoined-gendered-scale-array" => CreateConjoinedGenderedScaleArrayExpression(builderRoot),
                "segmented-scale-array" => CreateSegmentedScaleArrayExpression(builderRoot),
                "stemmed-scale-array" => CreateStemmedScaleArrayExpression(builderRoot),
                "linked-vigesimal-scale-array" => CreateLinkedVigesimalScaleArrayExpression(builderRoot),
                "terminal-ordinal-scale-array" => CreateTerminalOrdinalScaleArrayExpression(builderRoot),
                "construct-state-scale-array" => CreateConstructStateScaleArrayExpression(builderRoot),
                "hyphenated-scale" => CreateHyphenatedScaleExpression(builderRoot),
                "hyphenated-scale-array" => CreateHyphenatedScaleArrayExpression(builderRoot),

View on GitHub (pinned to ffc2b77c0f)

Solutions

1. Remove the 'east-asian-scale-array' builder from the contract member — east-asian scales are auto-projected by the 'east-asian-grouped' engine in AddEngineMetricScaleWords.
2. If the locale uses the 'east-asian-grouped' engine, ensure its scale words are defined via smallUnitWords and largeUnits in the YAML, not through a builder contract.
3. If you need a different scale builder, choose one from the supported list (e.g., 'hyphenated-scale-array', 'segmented-scale-array').

Example fix

// before
new EngineContractMember(
    kind: "builder",
    sourcePath: "scales",
    builder: "east-asian-scale-array",
    ...)
// after — remove this member; east-asian-grouped engine handles scales directly
// (delete the EngineContractMember entirely from the contract's Members array)

// Validate that no contract member uses the guarded east-asian-scale-array builder:
foreach (var m in contract.Members)
    if (m.Builder == "east-asian-scale-array")
        throw new ArgumentException(
            "east-asian-scale-array is engine-internal; use the east-asian-grouped engine path instead.");

static bool IsBuilderAllowed(EngineContractMember m) =>
    m.Builder != "east-asian-scale-array";

When it happens

Trigger: An EngineContractMember is constructed with builder='east-asian-scale-array' and the builder dispatch reaches line 510. The switch arm unconditionally throws InvalidOperationException. This indicates the builder was referenced from a contract definition where it should never appear.

Common situations: Copy-pasting builder names from a reference list without checking which are engine-internal. Attempting to use east-asian scale words through a builder contract instead of the dedicated engine path. Misunderstanding the east-asian-grouped engine architecture.

Related errors

• Builder members require a builder name.
• Unsupported number-to-words builder '{member.Builder}'.
• Unsupported number-to-words contract member kind '{member.Ki
• Enum members require an enum type.
• Array-backed metric scale word contracts require a value pro

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/908f1d643aff6295. Report an issue: GitHub.