Nik Everett bcef1e7452 Better error message when _parent isn't an object (#21987)
If you make a mistake and specify a mapping like:
```
{
  "parent": {
    "properties": {}
  },
  "child": {
    "_parent": "parent",
    "properties": {}
  }
}
```

then the error message you get back amounts to
`Failed to parse mapping for [child]: can't cast a String to a Map`.
Since it doens't tell you *which* string can't be cast to a map you
have to dig through the stack trace to figure out what to fix. This
replaces the error message with:
```
Failed to parse mapping [child]: [_parent] must be an object containing [type]
```
so you can tell that the problem is with the `parent` field.
2016-12-09 11:33:31 -05:00
..
2016-11-29 18:34:55 -05:00