* [DOCS] Warn only one date format is added to the field date formats
When using multiple options in `dynamic_date_formats`, only one of the formats of the first document having a date matching one of the date formats provided will be used.
E.g.
```
PUT my-index-000001
{
"mappings": {
"dynamic_date_formats": [ "yyyy/MM", "MM/dd/yyyy"]
}
}
PUT my-index-000001/_doc/1
{
"create_date": "09/25/2015"
}
```
The generated mappings will be:
```
"mappings": {
"dynamic_date_formats": [
"yyyy/MM",
"MM/dd/yyyy"
],
"properties": {
"create_date": {
"type": "date",
"format": "MM/dd/yyyy"
}
}
},
```
Indexing a document with `2015/12` would lead to the `format` `"yyyy/MM"` being used for the `create_date`.
This can be misleading especially if the user is using multiple date formats on the same field.
The first document will determine the format of the `date` field being detected.
Maybe we should provide an additional example, such as:
```
PUT my-index-000001
{
"mappings": {
"dynamic_date_formats": [ "yyyy/MM||MM/dd/yyyy"]
}
}
```
My wording is not great, so feel free to amend/edit.
* Update docs/reference/mapping/dynamic/field-mapping.asciidoc
Reword and add code example
* Turned discussion of the two syntaxes into an admonition
* Fix failing tests
Co-authored-by: Abdon Pijpelink <abdon.pijpelink@elastic.co>
2d3bcc483d