Raise exception on nil status

lib/faraday/error.rb

@@ -13,7 +13,10 @@ def initialize(exc, response = nil)
         super(exc.message)
         @wrapped_exception = exc
       elsif exc.respond_to?(:each_key)
-        super("the server responded with status #{exc[:status]}")
+        nil_status_message = 'the server responded with a nil status'
+        status_exists_msg = "the server responded with status #{exc[:status]}"
+        message = exc[:status].nil? ? nil_status_message : status_exists_msg
+        super(message)
         @response = exc
       else
         super(exc.to_s)
@@ -69,6 +72,10 @@ class ConflictError < ClientError
   class UnprocessableEntityError < ClientError
   end
 
+  # Raised by Faraday::Response::RaiseError in case of a nil status in response.
+  class NilStatusError < ClientError
+  end
+
   # Faraday server error class. Represents 5xx status responses.
   class ServerError < Error
   end

lib/faraday/response/raise_error.rb

@@ -28,6 +28,8 @@ def on_complete(env)
           raise Faraday::ConflictError, response_values(env)
         when 422
           raise Faraday::UnprocessableEntityError, response_values(env)
+        when nil
+          raise Faraday::NilStatusError, response_values(env)
         when ClientErrorStatuses
           raise Faraday::ClientError, response_values(env)
         when ServerErrorStatuses

spec/faraday/response/raise_error_spec.rb

@@ -14,6 +14,7 @@
         stub.get('conflict') { [409, { 'X-Reason' => 'because' }, 'keep looking'] }
         stub.get('unprocessable-entity') { [422, { 'X-Reason' => 'because' }, 'keep looking'] }
         stub.get('4xx') { [499, { 'X-Reason' => 'because' }, 'keep looking'] }
+        stub.get('nil-status') { [nil, { 'X-Reason' => 'because' }, 'keep looking'] }
         stub.get('server-error') { [500, { 'X-Error' => 'bailout' }, 'fail'] }
       end
     end
@@ -72,6 +73,13 @@
     end
   end
 
+  it 'raises Faraday::NilStatusError for nil status in response' do
+    expect { conn.get('nil-status') }.to raise_error(Faraday::NilStatusError) do |ex|
+      expect(ex.message).to eq('the server responded with a nil status')
+      expect(ex.response[:headers]['X-Reason']).to eq('because')
+    end
+  end
+
   it 'raises Faraday::ClientError for other 4xx responses' do
     expect { conn.get('4xx') }.to raise_error(Faraday::ClientError) do |ex|
       expect(ex.message).to eq('the server responded with status 499')