Leniency makes simple_query_string query a match_all

[shoteff]

As far as I can see since 1.3.3 when query is using "lenient" parameter it yelds results when we have format based failures (at least in 1.3.2 it does not return any results).
When searching by non-existing subfields (i.e. "field.nonexisting") no errors and no results are found (which seems to be correct)
The problem comes when I combine queries from both types - with "lenient" and format failure and with non-existing fields in a "should" boolean query
I'm tested with 1.3.4 version and 1.4.0-beta1
Here are the structure, test data and queries I tested with:
Structure
https://gist.github.com/shoteff/3ee9f2ad320410375c91
Data
https://gist.github.com/shoteff/f5c23bd6bb85f6fecdc9
Queries - here I also described what is working and what not
https://gist.github.com/shoteff/20fa2411ede09068ce95

[clintongormley]

Simple demo:

DELETE t

PUT /t/test/1
{
    "id": 1,
    "title": "this is test1"
}

GET /_validate/query?explain
{
  "query": {
    "bool": {
      "should": [
        {
          "simple_query_string": {
            "query": "this",
            "fields": [
              "id",
              "title"
            ],
            "default_operator": "and",
            "lenient": true
          }
        }
      ]
    }
  }
}

The above results in a match-all query:

{
   "valid": true,
   "_shards": {
      "total": 1,
      "successful": 1,
      "failed": 0
   },
   "explanations": [
      {
         "index": "t",
         "valid": true,
         "explanation": "*:*"
      }
   ]
}