mikefarah/yq · error

could not parse datetime of [%v] using layout [%v]: %w

Error message

could not parse datetime of [%v] using layout [%v]: %w

What it means

Inside the tz operator's per-node loop, parseDateTime could not interpret the node's scalar value using the currently active datetime layout (context.GetDateTimeLayout()). The value being converted and the layout are both printed; either the value is not a datetime at all or it uses a format that does not match the configured layout.

Source

Thrown at pkg/yqlib/operator_datetime.go:117

	timezoneStr, err := getStringParameter("timezone", d, context, expressionNode.RHS)
	layout := context.GetDateTimeLayout()

	if err != nil {
		return Context{}, err
	}
	var results = list.New()

	timezone, err := time.LoadLocation(timezoneStr)
	if err != nil {
		return Context{}, fmt.Errorf("could not load tz [%v]: %w", timezoneStr, err)
	}

	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)

		parsedTime, err := parseDateTime(layout, candidate.Value)
		if err != nil {
			return Context{}, fmt.Errorf("could not parse datetime of [%v] using layout [%v]: %w", candidate.GetNicePath(), layout, err)
		}
		tzTime := parsedTime.In(timezone)

		results.PushBack(candidate.CreateReplacement(ScalarNode, candidate.Tag, tzTime.Format(layout)))
	}

	return context.ChildContext(results), nil
}

func parseUnixTime(unixTime string) (time.Time, error) {
	seconds, err := strconv.ParseFloat(unixTime, 64)

	if err != nil {
		return time.Now(), err
	}

	return time.UnixMilli(int64(seconds * 1000)), nil
}

View on GitHub (pinned to 8b5af0694b)

Solutions

1. Set the matching layout first, e.g. --datetime-format / with_datetime_format before tz
2. Ensure the node values really are datetimes (filter or select them first)
3. Fix malformed datetime strings in the source data

When it happens

Trigger: Thrown at pkg/yqlib/operator_datetime.go:117 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mikefarah/yq@8b5af0694b (2026-09-05). Data as JSON: /api/errors/ad8729bf441d8583. Report an issue: GitHub.