paperclipai/paperclip · error

Invalid semver comparison: '${left}' vs '${right}'

Error message

Invalid semver comparison: '${left}' vs '${right}'

What it means

Internal guard in compareSemver: parseSemver failed on one of the two version strings, so they are not valid semver and cannot be ordered. Usually means a malformed version in a manifest or host version; the non-semver string is at fault.

Source

Thrown at server/src/services/plugin-loader.ts:1015

function compareIdentifiers(left: string, right: string): number {
  const leftIsNumeric = /^\d+$/.test(left);
  const rightIsNumeric = /^\d+$/.test(right);

  if (leftIsNumeric && rightIsNumeric) {
    return Number(left) - Number(right);
  }

  if (leftIsNumeric) return -1;
  if (rightIsNumeric) return 1;
  return left.localeCompare(right);
}

function compareSemver(left: string, right: string): number {
  const leftParsed = parseSemver(left);
  const rightParsed = parseSemver(right);

  if (!leftParsed || !rightParsed) {
    throw new Error(`Invalid semver comparison: '${left}' vs '${right}'`);
  }

  const coreOrder = (
    ["major", "minor", "patch"] as const
  ).map((key) => leftParsed[key] - rightParsed[key]).find((delta) => delta !== 0);
  if (coreOrder) {
    return coreOrder;
  }

  if (leftParsed.prerelease.length === 0 && rightParsed.prerelease.length === 0) {
    return 0;
  }
  if (leftParsed.prerelease.length === 0) return 1;
  if (rightParsed.prerelease.length === 0) return -1;

  const maxLength = Math.max(leftParsed.prerelease.length, rightParsed.prerelease.length);
  for (let index = 0; index < maxLength; index += 1) {
    const leftId = leftParsed.prerelease[index];

View on GitHub (pinned to 120ae5428f)

Solutions

1. Fix the malformed semver string(s) in the plugin manifest or host version pin; both sides of the comparison must be valid semver like '1.2.3'.

When it happens

Trigger: Thrown at server/src/services/plugin-loader.ts:1015 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of paperclipai/paperclip@120ae5428f (2026-08-18). Data as JSON: /api/errors/7ef15225ffb0b4cc. Report an issue: GitHub.