SpringBoot : characters are removed from application.yaml keys in mapped values when using @ConfigurationProperties

With a configuration properties class like this:

@ConfigurationProperties(prefix = "something")
data class MyConfigurationProperties(val values: Map<String, String>)

I would expect to be able to provide the following application.yaml:

something.values:
  "urn:some:specifier": hello world
  "urn:another:specifier": cool stuff

And then expect to receive MyConfigurationProperties.values as:

mapOf(
  "urn:some:specifier" to "hello world",
  "urn:another:specifier" to "cool stuff",
)

But the actual received values are:

mapOf(
  "urnsomespecifier" to "hello world",
  "urnanotherspecifier" to "cool stuff",
)

Comment From: quaff

It can be reproduced by java:

package com.example.demo;

import java.util.Map;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

import com.example.demo.DemoApplication.MyConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties(MyConfigurationProperties.class)
public class DemoApplication {

    public static void main(String[] args) {
        try (var ctx = SpringApplication.run(DemoApplication.class, args)) {
            System.out.println(ctx.getBean(MyConfigurationProperties.class));
        }
    }

    @ConfigurationProperties(prefix = "something")
    public record MyConfigurationProperties(Map<String, String> values) {

    }
}

Comment From: quaff

Here is a workaround:

something:
  values[urn:some:specifier]: hello world
  values[urn:another:specifier]: cool stuff

Comment From: wilkinsona

Thanks, @quaff. That's not a workaround, it's the documented way to preserve keys as-is when binding to a map.