Request parameters are not correctly pct-encoded in the Request Line

Hi,

I have noticed that when a request parameter contains parameters that "look" URL-encoded, feign skips encoding the % character.
For a basic example such as :
@RequestLine("GET /path?param={param}") void test(@Param("param") String value);
I have reproduced the below encoding examples :

        "label" => "label" (ok)
        "labelWithEscaped\\_Symbol" => "labelWithEscaped%5C_Symbol" (ok)
        "labelWithEscaped\\%Symbol" => "labelWithEscaped%5C%25Symbol" (ok)
        "filterWith%Symbol" => "filterWith%25Symbol" (ok)
        "filterWith%25Symbol" => "filterWith%25Symbol" (NOK - same encoding as above)
        "%2500%25" => "%2500%25" (NOK - % should be encoded)
        "%00%" => "%00%25" (NOK - first % should be encoded)
        "%25%20GA%20%25", "%25%20GA%20%25"  (NOK - % should be encoded)
        "%25 %25GA%25 %25", "%2525%20%2525GA%2525%20%2525" (OK; the presence of a reserved char other than % seem to force the whole value to be correctly encoded)

I have attached a small case to reproduce it here :
feign-query-bug.zip

I also note that there is a similar issue here : #1225
What I can observe is :

• The issue is still active at head (feign-core 12.1)
• The behavior has become a bit 'random' depending on the variable value between versions 10.1.0 and 11.8. It seems now that reserved characters force the "%" characters to be properly tackled.
• The issue appears whether the Request parameter is used as a query parameter (/path?param={value}) or in the path (/path/{value})

I first observed this in a service where the end user can use queries to search in a repository. The service calls another service using feign, and '%' can be used as a wildcard parameter. Anytime '%00' is used for example, the resulting query is incorrect.
But in general, when the Request Parameter value comes from uncontrolled input, which is frequent it can contain any sort of URL-encoded like value.

Is there any chance to see this fixed ?

Thanks,

Adrien

Start by reproducing the examples from the issue with the attached feign-query-bug.zip case against feign-core 12.1, then inspect the request-parameter encoding path for both query and path values. Done means percent signs in URL-encoded-looking input are encoded consistently without breaking the other examples, with regression coverage for the reported cases.