SpringBoot Configuration property parsing list has unexpected behavior

Hi, so I think there is an unexpected behavior around the configuration parsing

See the following application.yml

some:
  values-string: "this is a string"
  values-string-list: "this, is, a, list"

And my configuration class

@Configuration
@Getter
public class SomeConfig {
    @Value("${some.values-string}")
    private List<String> valuesString = new ArrayList<>();

    @Value("${some.values-string-list}")
    private List<String> valuesStringList = new ArrayList<>();
}

Then we will have the following in SomeConfig

valuesString == ["this is a string"]
valuesStringList == ["this", "is", "a", "list"]

I would have expected valuesStringList to be ["this, is, a, string"]

Comment From: wilkinsona

This is to be expected and is described in table 3 of this section of the documentation where it says that a list in a YAML file can be declared using "standard YAML list syntax or comma-separated values". When you declare a list as a comma-separated value, it's automatically split on those commas. If you want it to be a single value containing commas, declare it as a list with a single entry:

some:
  values-string:
      - "this is a string"
  values-string-list
      - "this, is, a, list"

The same applies to properties files although the syntax is different:

some.values-string[0]=this is a string
some.values-string-list[0]=this, is, a, list

You may also need to use @ConfigurationProperties rather than @Value to consume the values.

Comment From: AminArria

Thanks for quick reply, missed that comment in the docs