few extra changes to appease the type checker

lib/httpx/connection/http1.rb

@@ -322,7 +322,7 @@ module HTTPX
     end
 
     def join_body(request)
-      return if request.empty?
+      return if request.body.empty?
 
       while (chunk = request.drain_body)
         log(color: :green) { "<- DATA: #{chunk.bytesize} bytes..." }
@@ -331,7 +331,9 @@ module HTTPX
         throw(:buffer_full, request) if @buffer.full?
       end
 
-      raise request.drain_error if request.drain_error
+      return unless (error = request.drain_error)
+
+      raise error
     end
 
     def join_trailers(request)
@@ -358,7 +360,7 @@ module HTTPX
     }.freeze
 
     def capitalized(field)
-      UPCASED[field] || field.to_s.split("-").map(&:capitalize).join("-")
+      UPCASED[field] || field.split("-").map(&:capitalize).join("-")
     end
   end
   Connection.register "http/1.1", Connection::HTTP1

lib/httpx/connection/http2.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "securerandom"
-require "io/wait"
 require "http/2/next"
 
 module HTTPX
@@ -218,7 +217,7 @@ module HTTPX
       log(level: 1, color: :yellow) do
         request.headers.merge(extra_headers).each.map { |k, v| "#{stream.id}: -> HEADER: #{k}: #{v}" }.join("\n")
       end
-      stream.headers(request.headers.each(extra_headers), end_stream: request.empty?)
+      stream.headers(request.headers.each(extra_headers), end_stream: request.body.empty?)
     end
 
     def join_trailers(stream, request)
@@ -234,7 +233,7 @@ module HTTPX
     end
 
     def join_body(stream, request)
-      return if request.empty?
+      return if request.body.empty?
 
       chunk = @drains.delete(request) || request.drain_body
       while chunk
@@ -249,7 +248,9 @@ module HTTPX
         chunk = next_chunk
       end
 
-      on_stream_refuse(stream, request, request.drain_error) if request.drain_error
+      return unless (error = request.drain_error)
+
+      on_stream_refuse(stream, request, error)
     end
 
     ######
@@ -257,8 +258,10 @@ module HTTPX
     ######
 
     def on_stream_headers(stream, request, h)
-      if request.response && request.response.version == "2.0"
-        on_stream_trailers(stream, request, h)
+      response = request.response
+
+      if response.is_a?(Response) && response.version == "2.0"
+        on_stream_trailers(stream, response, h)
         return
       end
 
@@ -274,11 +277,11 @@ module HTTPX
       handle(request, stream) if request.expects?
     end
 
-    def on_stream_trailers(stream, request, h)
+    def on_stream_trailers(stream, response, h)
       log(color: :yellow) do
         h.map { |k, v| "#{stream.id}: <- HEADER: #{k}: #{v}" }.join("\n")
       end
-      request.response.merge_headers(h)
+      response.merge_headers(h)
     end
 
     def on_stream_data(stream, request, data)
@@ -304,7 +307,7 @@ module HTTPX
         emit(:response, request, response)
       else
         response = request.response
-        if response.status == 421
+        if response && response.status == 421
           ex = MisdirectedRequestError.new(response)
           ex.set_backtrace(caller)
           emit(:error, request, ex)

lib/httpx/headers.rb

@@ -57,7 +57,7 @@ module HTTPX
     def merge(other)
       headers = dup
       other.each do |field, value|
-        headers[field] = value
+        headers[downcased(field)] = value
       end
       headers
     end

lib/httpx/parser/http1.rb

@@ -60,7 +60,7 @@ module HTTPX
         (m = %r{\AHTTP(?:/(\d+\.\d+))?\s+(\d\d\d)(?:\s+(.*))?}in.match(@buffer)) ||
           raise(Error, "wrong head line format")
         version, code, _ = m.captures
-        raise(Error, "unsupported HTTP version (HTTP/#{version})") unless VERSIONS.include?(version)
+        raise(Error, "unsupported HTTP version (HTTP/#{version})") unless version && VERSIONS.include?(version)
 
         @http_version = version.split(".").map(&:to_i)
         @status_code = code.to_i

lib/httpx/plugins/multipart/mime_type_detector.rb

@@ -17,7 +17,7 @@ module HTTPX
 
       elsif defined?(MimeMagic)
 
-        def call(file, *)
+        def call(file, _)
           mime = MimeMagic.by_magic(file)
           mime.type if mime
         end
@@ -25,7 +25,7 @@ module HTTPX
       elsif system("which file", out: File::NULL)
         require "open3"
 
-        def call(file, *)
+        def call(file, _)
           return if file.eof? # file command returns "application/x-empty" for empty files
 
           Open3.popen3(*%w[file --mime-type --brief -]) do |stdin, stdout, stderr, thread|
@@ -56,7 +56,7 @@ module HTTPX
 
       else
 
-        def call(*); end
+        def call(_, _); end
 
       end
     end

lib/httpx/plugins/multipart/part.rb

@@ -8,7 +8,7 @@ module HTTPX
       def call(value)
         # take out specialized objects of the way
         if value.respond_to?(:filename) && value.respond_to?(:content_type) && value.respond_to?(:read)
-          return [value, value.content_type, value.filename]
+          return value, value.content_type, value.filename
         end
 
         content_type = filename = nil
@@ -19,7 +19,7 @@ module HTTPX
           value = value[:body]
         end
 
-        value = value.open(:binmode => true) if Object.const_defined?(:Pathname) && value.is_a?(Pathname)
+        value = value.open(File::RDONLY) if Object.const_defined?(:Pathname) && value.is_a?(Pathname)
 
         if value.is_a?(File)
           filename ||= File.basename(value.path)

lib/httpx/request.rb

@@ -46,9 +46,10 @@ module HTTPX
       @options = Options.new(options)
       @uri     = Utils.to_uri(uri)
       if @uri.relative?
-        raise(Error, "invalid URI: #{@uri}") unless @options.origin
+        origin = @options.origin
+        raise(Error, "invalid URI: #{@uri}") unless origin
 
-        @uri = @options.origin.merge(@uri)
+        @uri = origin.merge(@uri)
       end
 
       raise(Error, "unknown method: #{verb}") unless METHODS.include?(@verb)
@@ -96,7 +97,7 @@ module HTTPX
     def response=(response)
       return unless response
 
-      if response.status == 100
+      if response.is_a?(Response) && response.status == 100
         @informational_status = response.status
         return
       end
@@ -156,7 +157,7 @@ module HTTPX
 
     class Body < SimpleDelegator
       class << self
-        def new(*, options)
+        def new(_, options)
           return options.body if options.body.is_a?(self)
 
           super