expandQueryParams methos in HierarchicalUriComponents.java has bug

[smallflyfly250]

In HierarchicalUriComponents.java , expandQueryParams method want the params expand to uri, but for this method is not.

you can find this issue by use RestTemplate.exchange(String url, HttpMethod method, @nullable HttpEntity requestEntity, Class responseType, Map uriVariables) method.
Through this method, we can find stack trace calls HierarchicalUriComponents.expandQueryParams method,。 During this calling process，no assignment to the queryParams property in this class anywhere， so queryParams size is zero, alwalys can not append variables.

[bclozel]

Instead of explaining where you think the problem is in the codebase please share a minimal sample that reproduces the problem and explain the expected behavior.

[remeio]

For no assignment to the queryParams property in this class anywhere, It is not correct. queryParams will assign on constructor.

# On constructor
this.queryParams = query != null ? CollectionUtils.unmodifiableMultiValueMap(query) : EMPTY_QUERY_PARAMS;

For test case, it also work:

UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://example.com?name={name}").build();
Map<String, Object> map = new HashMap<>();
map.put("name", "foo");
UriComponents uriComponentsNew = uriComponents.expand(map);

assert uriComponents.getQueryParams().get("name").equals("foo");

I think @bclozel you can close this issue. No bug here.

[bclozel]

If I understand correctly, the expectation here is that uriVariables are applied as query parameters to the resulting URI. As pointed out by @remeio this is not the expected nor documented behavior. There are dedicated methods for query parameters, or as shown in the last comment, they can be used with URI variables.