Humanizr/Humanizer · error · InvalidOperationException

'{path}.provenance' must contain non-empty source identifier

Error message

'{path}.provenance' must contain non-empty source identifiers.

What it means

Thrown by ParseProvenance when iterating the provenance sequence and encountering an item that is not a SimpleYamlScalar or whose scalar value is empty/whitespace. Every provenance entry must be a non-empty source identifier string.

Source

Thrown at src/Humanizer.SourceGenerators/Common/DurationCaseModels.cs:1058

            if (!mapping.TryGetValue("provenance", out var value))
            {
                return required
                    ? throw new InvalidOperationException($"'{path}' must define provenance.")
                    : [];
            }

            if (value is not SimpleYamlSequence sequence)
            {
                throw new InvalidOperationException($"'{path}.provenance' must be a sequence.");
            }

            var result = ImmutableArray.CreateBuilder<string>(sequence.Items.Length);
            var seen = new HashSet<string>(StringComparer.Ordinal);
            foreach (var item in sequence.Items)
            {
                if (item is not SimpleYamlScalar scalar || string.IsNullOrWhiteSpace(scalar.Value))
                {
                    throw new InvalidOperationException(
                        $"'{path}.provenance' must contain non-empty source identifiers.");
                }

                if (!seen.Add(scalar.Value))
                {
                    throw new InvalidOperationException(
                        $"'{path}.provenance' contains duplicate source '{scalar.Value}'.");
                }

                result.Add(scalar.Value);
            }

            if (required && result.Count == 0)
            {
                throw new InvalidOperationException($"'{path}.provenance' must not be empty.");
            }

            return result.MoveToImmutable();

View on GitHub (pinned to ffc2b77c0f)

Solutions

Inspect each element of the provenance list at the reported path.
Remove or replace any non-scalar or empty/whitespace entries with a valid non-empty source ID string.
Rebuild to confirm all entries are valid scalars.

Example fix

# before (empty entry from trailing comma)
provenance: [cldr-42, ]
# after
provenance: [cldr-42]

Defensive patterns

Strategy: validation

Validate before calling

# Verify every provenance item is a non-empty string
# python: for item in unit['provenance']:
#     assert isinstance(item, str) and item.strip(), 'empty or non-scalar provenance entry'

Prevention

Avoid trailing commas in flow-style YAML lists that create empty entries.
Keep each provenance entry as a bare scalar string.
Run a YAML linter that flags empty list elements.

When it happens

Trigger: The provenance list contains a null/empty element, a mapping, a nested sequence, or a scalar value that is whitespace-only.

Common situations: A contributor leaves a trailing comma in a flow-style list creating an empty entry, or accidentally nests a mapping inside the provenance list. Also occurs when a source ID is accidentally left blank.

Related errors

AI-assisted analysis of Humanizr/Humanizer@ffc2b77c0f (2026-08-13). Data as JSON: /api/errors/4eda2bd625ae7601. Report an issue: GitHub.