Adding the same IP to runtime ACL file returns 500 instead of expected 409

[ignoreswing]

Steps to Reproduce

1. [POST] /services/haproxy/runtime/acl_file_entries

   • Add a new IP (192.168.50.2) to the runtime ACL file.
   • Initially, it responds with HTTP status code 201:

     curl --location 'https://192.168.30.169:5566/v2/services/haproxy/runtime/acl_file_entries?acl_id=4' \
     --header 'Content-Type: application/json' \
     --header 'Authorization: Basic aGFwcm94eTpQQHNzdzByZA==' \
     --data '{
       "value": "192.168.50.2"
     }'
     

2. Send the above API request again.

   • It returns a 500 error with the following message:

     {
         "code": 500,
         "message": "cannot add ACL files entry for 4: already exists"
     }
     

Expected Behavior

According to the documentation, in this case, where the specified resource already exists, it should respond with status code 409.

Actual Behavior

It returns a 500 error.

Your Environment

• HAProxy version 2.8.9
• HAProxy Data Plane API v2.9.3 build 59f34ea
• Ubuntu 22.04.1 LTS