ruby on rails - swagger_doc.json returns wrong swagger doc urls -

my https://x.y/api/swagger_doc.json returns this:

{"apiversion":"0.1","swaggerversion":"1.2","produces":["application/xml","application/json","application/vnd.api+json","text/plain"],"apis":[{"path":"/ping.{format}","description":"operations pings"},{"path":"/ping_dev.{format}" 

notice path pointing /ping.{format} should point /swagger_doc/ping.json. because of swagger ui gives me error:

unable read api 'friends' path https://x.y:443/api/ping.json 

i can access manually ping.json form https://x.y:443/api/swagger_doc/ping.json. content needed swagger ui:

{"apiversion":"0.1","swaggerversion":"1.2","resourcepath":"/ping","produces":["application/xml","application/json","application/vnd.api+json","text/plain"],"apis":[{"path":"/api/ping.{format}","operations":[{"notes":"","summary":"returns pong.","nickname":"get-api-ping---format-","method":"get","parameters":[],"type":"void"}]}],"basepath":"http://local.dime.com:3000"} 

any idea appreciated solve mystery:

huh.. tough one.

it grape-swagger bug:

in grape-swagger (0.7.2)

:path => "#{url_base}/#{local_route}#{url_format}", 

in grape-swagger (0.8.0)

path: "/#{local_route}#{url_format}",