Crash in `main` — "Invalid parameter not satisfying: numberOfValues > 0"

[stuartbreckenridge]

Crashing when creating placeholders. There's an underlying NSParameterAssert(numberOfValues > 0); in the rs_SQLValueListWithPlaceholders call.

func unreadCount(feedIDs: Set<String>, since: Date, database: FMDatabase) -> Int? {

    let placeholders = NSString.rs_SQLValueList(withPlaceholders: UInt(feedIDs.count))! // <-- Thread 2: "Invalid parameter not satisfying: numberOfValues > 0"
    let sql = "select count(*) from articles natural join statuses where feedID in \(placeholders) and (datePublished > ? or (datePublished is null and dateArrived > ?)) and read=0;"

    var parameters = [Any]()
    parameters += Array(feedIDs) as [Any]
    parameters += [since] as [Any]
    parameters += [since] as [Any]

    let unreadCount = database.count(sql: sql, parameters: parameters, tableName: name)
    return unreadCount
}