Humanizr/Humanizer · error · InvalidOperationException

Inverted tens token '{property.Name}' must map to an integer

Error message

Inverted tens token '{property.Name}' must map to an integer value.

What it means

Thrown while building an InvertedTensToken[] when the YAML node is a mapping but one of its values is not an integer. The builder maps each token name to an integer base value; a non-numeric value (or a number that fails TryGetInt64) cannot be turned into the token's numeric component.

Source

Thrown at src/Humanizer.SourceGenerators/Common/GenerationHelpers.cs:1227

    }

    static string CreateInvertedTensTokenArrayExpression(JsonElement arrayElement)
    {
        if (arrayElement.ValueKind is not (JsonValueKind.Array or JsonValueKind.Object))
        {
            throw new InvalidOperationException("Expected JSON array or mapping.");
        }

        var builder = new StringBuilder("new InvertedTensToken[] { ");
        var first = true;

        if (arrayElement.ValueKind == JsonValueKind.Object)
        {
            foreach (var (Name, Value) in arrayElement.EnumerateObject()
                         .Select(static property =>
                         {
                             return property.Value.ValueKind != JsonValueKind.Number || !property.Value.TryGetInt64(out var value)
                                 ? throw new InvalidOperationException($"Inverted tens token '{property.Name}' must map to an integer value.")
                                 : (property.Name, Value: value);
                         })
                         .OrderByDescending(static entry => entry.Value)
                         .ThenBy(static entry => entry.Name, StringComparer.Ordinal))
            {
                if (!first)
                {
                    builder.Append(", ");
                }

                builder.Append("new(");
                builder.Append(QuoteLiteral(Name));
                builder.Append(", ");
                builder.Append(Value.ToString(CultureInfo.InvariantCulture));
                builder.Append(')');
                first = false;
            }
        }

View on GitHub (pinned to ffc2b77c0f)

Solutions

In the inverted-tens mapping, set each token's value to an integer literal (no quotes): einundzwanzig: 21.
Ensure no value is a string, boolean, or decimal that cannot be parsed as int64.
Rebuild; the generator will name the first offending token if others remain.

Example fix

# before
invertedTens:
  einundzwanzig: 'einundzwanzig'
# after
invertedTens:
  einundzwanzig: 21

Defensive patterns

Strategy: validation

Validate before calling

# For every key in the inverted-tens mapping, the value must be an integer.
#   rg -B1 -A1 "invertedTens" src/Humanizer/Locales/<code>.yml
# Each token line should read '<token>: <integer>' with an unquoted number.

Prevention

Always use unquoted integer values for inverted-tens token magnitudes.
Never reuse the token word as its own value.
Build locally so the generator names the first offending token.

When it happens

Trigger: A locale YAML defines the inverted-tens section as a mapping where at least one entry's value is a string, boolean, or a non-integer number. The Select lambda checks ValueKind and TryGetInt64, then throws naming the offending property (the token string).

Common situations: A contributor adds a token but leaves its value as a word (e.g. 'einundzwanzig: einundzwanzig') instead of the integer 21, or uses a float. The build-time generator output names the specific token that is wrong.

Related errors

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/d1cae9fa3f11a974. Report an issue: GitHub.