aws-autoscaling-common: intervals can never be absolute

[cheruvian]

Describe the bug

In this function, absolute changes get changed to all undefined which then breaks the validateAtMostOneUndefined call.

export function normalizeIntervals(intervals: ScalingInterval[], changesAreAbsolute: boolean): CompleteScalingInterval[] {
  // Make intervals a complete numberline
  const full = orderAndCompleteIntervals(intervals);
  // Add 'undefined's in uncovered areas of the number line
  makeGapsUndefined(full);

  // In case of relative changes, treat 0-change also as 'undefined' (= no change action)
  if (!changesAreAbsolute) { makeZerosUndefined(full); }

  // Combine adjacent undefines and make sure there's at most one of them
  combineUndefineds(full);
  validateAtMostOneUndefined(full);

  return full;
}

This means that any step scaling with AdjustmentType.EXACT_CAPACITY and > 2 steps will fail validation

Expected Behavior

Allow this use case.

Current Behavior

Error: Can have at most one no-change interval, got [{"lower":0.99,"upper":1},{"lower":1.99,"upper":2},{"lower":2.99,"upper":3},{"lower":3.99,"upper":4},{"lower":4.99,"upper":5},{"lower":5.99,"upper":6},{"lower":6.99,"upper":7},{"lower":7.99,"upper":8},{"lower":8.99,"upper":9}]

Reproduction Steps

    scalableTaskCount.scaleOnMetric(`TargetScaling`, {
      scalingSteps: [
        { upper: 0.99, change: 0 },
        { lower: 1, upper: 1.99, change: 1 },
        { lower: 2, change: 2 }
      ],
      metric: targetMetric,
      adjustmentType: AdjustmentType.EXACT_CAPACITY,
    });

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

latest on gh

Framework Version

No response

Node.js Version

20.14.0

OS

OSX

Language

TypeScript

Language Version

No response

Other information

No response

[khushail]

Hey @cheruvian , thanks for reaching out. Could you please share the complete repro code for this issue?

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