Humanizr/Humanizer · error · InvalidOperationException

Unsupported inflection countability '{countability}'.

Error message

Unsupported inflection countability '{countability}'.

What it means

The inflection catalog encodes noun countability as a bitmask from a fixed vocabulary: 'count', 'mass', 'collective', and 'plural-only'. Any other countability string in the YAML is rejected by GetCountabilityMask because it cannot be mapped to a bit position.

Source

Thrown at src/Humanizer.SourceGenerators/Generators/ProfileCatalogs/InflectionCatalogValidation.cs:409

                    out var scriptValue);
                mask |= scriptValue;
            }

            return (uint)mask;
        }

        static byte GetCountabilityMask(ImmutableArray<string> countabilities)
        {
            byte mask = 0;
            foreach (var countability in countabilities)
            {
                mask |= countability switch
                {
                    "count" => 1 << 0,
                    "mass" => 1 << 1,
                    "collective" => 1 << 2,
                    "plural-only" => 1 << 3,
                    _ => throw new InvalidOperationException(
                        $"Unsupported inflection countability '{countability}'.")
                };
            }

            return mask;
        }

        static ImmutableArray<string> NormalizeGuards(
            ImmutableArray<string> values,
            string casing,
            ImmutableArray<string> ownerScripts,
            string subject)
        {
            return NormalizeAuthoredTexts(
                values,
                casing,
                ownerScripts,
                subject,

View on GitHub (pinned to ffc2b77c0f)

Solutions

1. Change the countability value to one of the four supported labels: 'count', 'mass', 'collective', or 'plural-only'.
2. If the concept maps to multiple categories, list them as separate entries in the countability array.
3. Check the locale authoring guide for the canonical countability vocabulary.

Example fix

# before
lexemes:
  - id: 'water'
    countability: ['uncountable']
# after
lexemes:
  - id: 'water'
    countability: ['mass']

# Before building, verify countability values are from the allowed set.
python3 -c "
import yaml, sys
ALLOWED = {'count','mass','collective','plural-only'}
for f in sys.argv[1:]:
    d = yaml.safe_load(open(f))
    owners = (d.get('inflection',{}).get('owners') or [])
    for owner in owners:
        for lex in (owner.get('lexemes') or []):
            for c in (lex.get('countability') or []):
                if c not in ALLOWED:
                    print(f'{f}: unsupported countability {c!r} on lexeme {lex.get("id","")!r}')
" src/Humanizer/Locales/*.yml

When it happens

Trigger: A lexeme's or rule's 'countability' field contains a value not in the set {count, mass, collective, plural-only}. The switch expression's default arm throws. For example, 'uncountable' or 'singular-only' would trigger this.

Common situations: Using a synonym like 'uncountable' instead of 'mass'. Copying terminology from a different inflection framework with different countability labels. Typo in the countability string.

Related errors

• Productive evidence '{direction}' requires at least 100 atte
• {subject} references unknown source '{source}'.
• Inflection source '{entry.Key}' must define non-empty kind a
• Inflection source '{entry.Key}' {optionalProperty} must be a
• Inflection rule '{ruleId}' output must contain exactly one b

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/610a222a0788580b. Report an issue: GitHub.