The bug appears only in Tomcat, using Jetty it is not reproducible
Spring Boot v1.5.7.RELEASE
Apache Tomcat 8.5.20
* Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> GET /echo/YYYYYYY HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200
< Transfer-Encoding: chunked
< Date: Sat, 14 Oct 2017 13:12:37 GMT
<
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
YYYYYYY
^C`
Calling it again (sometimes it is required to be called several times) shows the following:
curl -v -N http://localhost:8080/echo/YYYYYYY 130 ↵
* Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> GET /echo/YYYYYYY HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.54.0
> Accept: */*
>
YYYYYYY
YYYYYYY
8
YYYYYYY
8
YYYYYYY
^C