Allow to map null value from yaml [SPR-15425]

Simon Stratmann opened SPR-15425 and commented

The following issue occured to me while using Spring Boot but is caused by Spring code.

With Spring Boot I have a String property that is mapped to an application.yml by using @ConfigurationProperties. The value in the yml file is null (or ~). But the values are initialized with “” (empty String). According to YAML specification it does allow null values.

The culprit is org.springframework.beans.factory.config.YamlProcessor#buildFlattenedMap which executes result.put(key, (value != null ? value : "")).

I’ve extended the file and configured it to be used and this seems to work fine. But I have to take over a lot of final and private code which makes it a bit brittle. I think the class should support null values, explicitly remark that their converted to “” or make a change in behavior a bit more comfortable.

Code excerpts:

test:
    setting: ~

@ConfigurationProperties("test")
public class Test {

    String setting;

    public void setSetting(String setting) {
        this.setting = setting; //Will set "setting" to "" instead of null
    }
}

Thanks for your time.

Affects: 4.3.7

Attachments:

• demo.zip (5.25 kB)

Issue Links:

• #21310 YamlPropertiesFactoryBean loses entries in the YAML document that have an empty array value

4 votes, 5 watchers