title: How to distinguish an empty list from a list of one empty parameter in Swagger?
body: <p>I am implementing a in-house code generator that implements Swagger 2.0 (OpenAPI).</p>
  
  <p>I am facing an ambiguity that I find impossible to resolve from reading the specifications.</p>
  
  <p>Say we have an <code>array</code> type of <code>strings</code> (be it in <code>path</code> or <code>query</code>, it's the same thing here), which is comma separated.</p>
  
  <ul>
  <li>A list of two elements is represented as: <code>a,b</code></li>
  <li>A list of one element is represented as: <code>a</code></li>
  <li>An empty list is represented as: </li>
  <li>A list of two empty elements is represented as : <code>,</code></li>
  <li>A list of one empty element is represented as : </li>
  </ul>
  
  <p>Clearly, having the same representation for an <em>empty list</em> and a <em>list of one empty element</em> is a problem. Of course, I could decide that a list of one empty element is represented as <code>,</code> (Python does that for it's tuples) but then how should I represent a list of two empty elements ?</p>
  
  <p>Of course in the case of the query parameter, I can just solve the ambiguity with the absence of the parameter itself (but that does not solve the problem for <code>path</code> parameters, nor does it give me any guarantee about what other implementations do).</p>
  
  <p>Anyway, I don't want to "decide" anything but rather implement the spec. to maximize interoperability. However, I can't find any authoritative source as to how to handle that situation.</p>
  
  <p>Are empty strings forbidden in swagger strings arrays ? Should I ignore them ? Consider those lists invalid ?</p>
  
  <p>In short: what should I do in those cases ?</p>