Gateway MVC: space character in POSTed JSON leads to IOException: insufficient data written

[mindhaq]

Describe the bug

I'm using spring-boot 3.2.5 with spring cloud 2023.0.1 and JDK 21

I'm using Proxy Exchange Gateway with Spring MVC.

When I POST JSON data to a proxy controller that contains a space character, the proxy exchange fails with the exception in the title:

java.io.IOException: insufficient data written
	at java.base/sun.net.www.protocol.http.HttpURLConnection$StreamingOutputStream.close(HttpURLConnection.java:3848) ~[na:na]
	at org.springframework.http.client.SimpleClientHttpRequest.executeInternal(SimpleClientHttpRequest.java:84) ~[spring-web-6.1.6.jar:6.1.6]
	at org.springframework.http.client.AbstractStreamingClientHttpRequest.executeInternal(AbstractStreamingClientHttpRequest.java:70) ~[spring-web-6.1.6.jar:6.1.6]
	at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66) ~[spring-web-6.1.6.jar:6.1.6]
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:889) ~[spring-web-6.1.6.jar:6.1.6]
	at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:740) ~[spring-web-6.1.6.jar:6.1.6]
	at org.springframework.cloud.gateway.mvc.ProxyExchange.exchange(ProxyExchange.java:347) ~[spring-cloud-gateway-mvc-4.1.2.jar:4.1.2]
	at org.springframework.cloud.gateway.mvc.ProxyExchange.post(ProxyExchange.java:308) ~[spring-cloud-gateway-mvc-4.1.2.jar:4.1.2]
	at com.mindhaq.demogatewayproxy.GatewayController.handlePost(GatewayController.kt:17) ~[main/:na]

       ....

With everything being the same, but not having any space characters in the JSON, there is no problem.

This was found while migrating a spring-boot monolith running on boot 2.2.x with netflix zuul which was updated to spring boot 3.2.x, cloud gateway, latest JDK etc. It took quite some time to reduce the error scenario to this.

Sample

I created a sample repository which proxies requests to httpbin.org

https://github.com/mindhaq/spring-demo-gateway-proxyexchange-mvc

This request fails with the exception above:

curl -X POST -H "Content-Type: application/json" -d '{"foo": "bar"}' http://localhost:8080/post 

This one works just fine:

curl -X POST -H "Content-Type: application/json" -d '{"foo":"bar"}' http://localhost:8080/post 

Going directly to httpbin.org works in both cases, so that is not the problem.

Do I miss any configuration or is this some deeper lying bug which got revealed by that space character?

[mindhaq]

It might be related to #3154