Function updateRsFromPrimary

src/sdam/topology_description.ts:372–493

(
  serverDescriptions: Map<string, ServerDescription>,
  serverDescription: ServerDescription,
  setName: string | null = null,
  maxSetVersion: number | null = null,
  maxElectionId: ObjectId | null = null
)

}

function updateRsFromPrimary(
  serverDescriptions: Map<string, ServerDescription>,
  serverDescription: ServerDescription,
  setName: string | null = null,
  maxSetVersion: number | null = null,
  maxElectionId: ObjectId | null = null
): [TopologyType, string | null, number | null, ObjectId | null] {
  const setVersionElectionIdMismatch = (
    serverDescription: ServerDescription,
    maxSetVersion: number | null,
    maxElectionId: ObjectId | null
  ) => {
    return (
      `primary marked stale due to electionId/setVersion mismatch:` +
      ` server setVersion: ${serverDescription.setVersion},` +
      ` server electionId: ${serverDescription.electionId},` +
      ` topology setVersion: ${maxSetVersion},` +
      ` topology electionId: ${maxElectionId}`
    );
  };
  setName = setName || serverDescription.setName;
  if (setName !== serverDescription.setName) {
    serverDescriptions.delete(serverDescription.address);
    return [checkHasPrimary(serverDescriptions), setName, maxSetVersion, maxElectionId];
  }

  if (serverDescription.maxWireVersion >= 17) {
    const electionIdComparison = compareObjectId(maxElectionId, serverDescription.electionId);
    const maxElectionIdIsEqual = electionIdComparison === 0;
    const maxElectionIdIsLess = electionIdComparison === -1;
    const maxSetVersionIsLessOrEqual =
      (maxSetVersion ?? -1) <= (serverDescription.setVersion ?? -1);

    if (maxElectionIdIsLess || (maxElectionIdIsEqual && maxSetVersionIsLessOrEqual)) {
      // The reported electionId was greater
      // or the electionId was equal and reported setVersion was greater
      // Always update both values, they are a tuple
      maxElectionId = serverDescription.electionId;
      maxSetVersion = serverDescription.setVersion;
    } else {
      // Stale primary
      // replace serverDescription with a default ServerDescription of type "Unknown"
      serverDescriptions.set(
        serverDescription.address,
        new ServerDescription(serverDescription.address, undefined, {
          error: new MongoStalePrimaryError(
            setVersionElectionIdMismatch(serverDescription, maxSetVersion, maxElectionId)
          )
        })
      );

      return [checkHasPrimary(serverDescriptions), setName, maxSetVersion, maxElectionId];
    }
  } else {
    const electionId = serverDescription.electionId ? serverDescription.electionId : null;
    if (serverDescription.setVersion && electionId) {
      if (maxSetVersion && maxElectionId) {
        if (