Humanizr/Humanizer · error · InvalidOperationException

Unsupported ordinal date engine '{profile.Engine}'.

Error message

Unsupported ordinal date engine '{profile.Engine}'.

What it means

Thrown during source generation by CreateConverterExpression when an ordinal-date profile's engine value is neither 'default' nor 'pattern'. The generator only supports these two engine identifiers for ordinal-date conversion; any other value causes the switch's default arm to fire.

Source

Thrown at src/Humanizer.SourceGenerators/Generators/ProfileCatalogs/OrdinalDateProfileCatalogInput.cs:179

            {
                builder.AppendLine();
                builder.AppendLine("#endif");
            }

            context.AddSource(sourceName, SourceText.From(builder.ToString(), Encoding.UTF8));
        }

        static string CreateConverterExpression(OrdinalDateProfileDefinition profile, string converterTypeName) =>
            profile.Engine switch
            {
                "default" => converterTypeName switch
                {
                    "PatternDateToOrdinalWordsConverter" => "new DefaultDateToOrdinalWordConverter()",
                    "PatternDateOnlyToOrdinalWordsConverter" => "new DefaultDateOnlyToOrdinalWordConverter()",
                    _ => throw new InvalidOperationException($"Unsupported default ordinal-date converter '{converterTypeName}'.")
                },
                "pattern" => CreatePatternExpression(profile, converterTypeName),
                _ => throw new InvalidOperationException($"Unsupported ordinal date engine '{profile.Engine}'.")
            };

        static string CreatePatternExpression(OrdinalDateProfileDefinition profile, string converterTypeName)
        {
            var pattern = GetRequiredString(profile.Root, "pattern");
            var hasGregorianMonths = profile.Months.Length > 0;
            var hasHijriMonths = profile.HijriMonths.Length > 0;
            var hasAnyMonthOverride = hasGregorianMonths || hasHijriMonths;

            if (hasAnyMonthOverride && ContainsAbbreviatedMonth(pattern))
            {
                throw new InvalidOperationException(
                    $"Ordinal date profile '{profile.ProfileName}' uses MMM (abbreviated month) " +
                    "which is not supported when calendar month overrides are active. " +
                    "Only MMMM (full month name) substitution is supported.");
            }

            if (hasAnyMonthOverride)

View on GitHub (pinned to ffc2b77c0f)

Solutions

1. Open the locale YAML and set the ordinal-date engine to either 'default' or 'pattern' (lowercase, exact spelling).
2. If the engine key is omitted, note that the default is 'pattern' (see AddProfile at line 73) — so this error only fires when an explicit non-matching value is present.
3. Remove the engine key entirely if you want the default 'pattern' behavior.

Example fix

# locale YAML — before
ordinalDate:
  engine: Default
  pattern: "dddd, d MMMM yyyy"

# after
ordinalDate:
  engine: pattern
  pattern: "dddd, d MMMM yyyy"

// Before building, validate that the ordinal-date engine value in each
// locale YAML is exactly 'default' or 'pattern' (lowercase, case-sensitive).
// If the engine key is omitted, 'pattern' is the implicit default.

When it happens

Trigger: A locale YAML has an ordinal-date block with an engine value that is misspelled, uses different casing (the switch is case-sensitive), or names an engine that was never implemented for ordinal dates.

Common situations: A maintainer copies a locale YAML from another feature (e.g. numberToWords) that uses a different engine name and forgets to change it to 'default' or 'pattern'. Or a typo such as 'Default' (capital D) or 'patten' breaks the case-sensitive match.

Related errors

• calendar.{key} items must be strings.
• Ordinal date profile '{profile.ProfileName}' uses MMM (abbre
• Ordinal date profile '{profile.ProfileName}' has calendar mo
• Ordinal date profile '{profile.ProfileName}' has calendar mo
• Billion-word cardinal strategy requires a singular billion w

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/804fad624416ae87. Report an issue: GitHub.