Humanizr/Humanizer · error · InvalidOperationException

Property '{propertyName}' must be an integer.

Error message

Property '{propertyName}' must be an integer.

What it means

GenerationHelpers.GetRequiredInt64 (GenerationHelpers.cs:227-233) first ensures the property exists (else error 110) then requires its JSON value to be a Number that fits int64. A float, a quoted string, a boolean, or an out-of-range number fails ValueKind/TryGetInt64 and throws.

Source

Thrown at src/Humanizer.SourceGenerators/Common/GenerationHelpers.cs:232

            ?? GetOptionalString(formatter.ProfileRoot, "pluralRule")
            ?? GetOptionalString(formatter.ProfileRoot, "resourceKeyDetector");
    }

    static bool GetBoolean(JsonElement element, string propertyName) =>
        element.TryGetProperty(propertyName, out var valueElement) &&
        valueElement.ValueKind == JsonValueKind.True;

    static JsonElement GetRequiredProperty(JsonElement element, string propertyName) =>
        element.TryGetProperty(propertyName, out var property)
            ? property
            : throw new InvalidOperationException($"Missing required property '{propertyName}'.");

    static long GetRequiredInt64(JsonElement element, string propertyName)
    {
        var property = GetRequiredProperty(element, propertyName);
        return property.ValueKind == JsonValueKind.Number && property.TryGetInt64(out var value)
            ? value
            : throw new InvalidOperationException($"Property '{propertyName}' must be an integer.");
    }

    static long? GetOptionalInt64(JsonElement element, string propertyName)
    {
        return !element.TryGetProperty(propertyName, out var property) || property.ValueKind != JsonValueKind.Number
            ? null
            : property.TryGetInt64(out var value) ? value : null;
    }

    /// <summary>
    /// Emits a generated <c>string[]</c> from either a plain YAML sequence or a sparse
    /// numeric-slot mapping.
    ///
    /// Supported source shapes:
    ///
    /// 1. Plain array:
    ///    <code>
    ///    unitsMap:

View on GitHub (pinned to ffc2b77c0f)

Solutions

1. Make the value an integer literal with no decimal point.
2. If it is a quoted string, remove the quotes so it parses as a JSON number.
3. Confirm the value is within int64 range.

Example fix

// before
{ "base": "10" }
// after
{ "base": 10 }

// Required integer must be a JSON number fitting int64 (C#)
if (!el.TryGetProperty(name, out var p) || p.ValueKind != JsonValueKind.Number || !p.TryGetInt64(out _))
    throw new InvalidOperationException($"Property '{name}' must be an integer");

static bool IsInt64(JsonElement el, string name) =>
    el.TryGetProperty(name, out var p) && p.ValueKind == JsonValueKind.Number && p.TryGetInt64(out _);

When it happens

Trigger: A required integer property holds a JSON float (1.5), a string ("5"), true/false, or a number too large for int64.

Common situations: YAML number parsed as a float due to a decimal point; value quoted as a string; locale data authored with a numeric-looking string.

Related errors

• Indexed string arrays require string values. Property '{prop
• Expected JSON object.
• Missing required property '{sourcePath}'.
• Missing required property '{propertyName}'.
• Expected JSON array.

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/97a0f3aac428c20b. Report an issue: GitHub.