Unexpected URI variables handling when expanded into already existing query parameter name (UriComponentsBuilder)

[christophejan]

With spring-web 6.2.5, I get the following behavior :

var uriOk = UriComponentsBuilder.fromUriString(“http://myhost?{pk1}={pv1}&{pk2}={pv2}”).buildAndExpand(“v1”, “v2”, “v3”, “v4”);
System.out.println(uriOk);

Output :

http://myhost?v1=v2&v3=v4

But :

var uriKo = UriComponentsBuilder.fromUriString(“http://myhost?{pk1}={pv1}&{pk2}={pv2}”).buildAndExpand(“v1”, “v2”, “v1”, “v4”);
System.out.println(uriKo);

Output :

http://myhost?v1=v4

I was expecting the following output for uriKo :

http://myhost?v1=v2&v1=v4

[rstoyanchev]

Superseded by #34783.