gohugoio/hugo · error

'increment' must not be 0

Error message

'increment' must not be 0

What it means

Thrown by Seq in the 3-argument form when the increment (second argument) is exactly 0 (line 460). A zero step would loop infinitely (val += 0 never progresses), so it is rejected before the size is computed.

Solutions

1. Use a non-zero increment: {{ seq 1 1 10 }} for step 1, {{ seq 10 -1 1 }} for step -1.
2. Clamp the computed step away from zero: {{ $step := cond (eq $step 0) 1 $step }} {{ seq 1 $step 10 }}.
3. Validate user-provided step params to reject 0 at the content/config level.

Example fix

// before
{{ seq 1 0 10 }}
// after
{{ seq 1 1 10 }}

{{ $step := cond (eq $step 0) 1 $step }}
{{ seq 1 $step 10 }}

When it happens

Trigger: Calling {{ seq 1 0 10 }} explicitly; passing a computed increment that resolves to 0 such as {{ seq 1 (sub $a $a) 10 }}; a front matter 'step' param set to 0.

Common situations: Dynamic step math collapsing to zero; user-configurable step params not bounded away from zero; defaulting a step variable to 0 by mistake.

Related errors

• 'increment' must be > 0
• 'increment' must be < 0
• size of result exceeds limit
• invalid arguments to Seq
• invalid number of arguments to Seq

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/fb7df680a7499257. Report an issue: GitHub.

Appendix: source

Thrown at tpl/collections/collections.go:461

		last = first
		if last == 0 {
			return []int{}, nil
		} else if last > 0 {
			first = 1
		} else {
			first = -1
			inc = -1
		}
	} else if len(intArgs) == 2 {
		last = intArgs[1]
		if last < first {
			inc = -1
		}
	} else {
		inc = intArgs[1]
		last = intArgs[2]
		if inc == 0 {
			return nil, errors.New("'increment' must not be 0")
		}
		if first < last && inc < 0 {
			return nil, errors.New("'increment' must be > 0")
		}
		if first > last && inc > 0 {
			return nil, errors.New("'increment' must be < 0")
		}
	}

	// sanity check
	if last < -maxSeqSize {
		return nil, errSeqSizeExceedsLimit
	}
	size := ((last - first) / inc) + 1

	// sanity check
	if size <= 0 || size > maxSeqSize {
		return nil, errSeqSizeExceedsLimit

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