Don't attempt to parse a nil response when hooking into Excon (#916)

CHANGELOG.md

@@ -13,6 +13,7 @@ Changelog
 - [patch] Improve error message for syntax error in ERB-using cassettes (#909)
 - [patch] Handle `use_cassette(..., erb: {})` (#908) 
 - [fix] Use fiber-local for `global_hook_disabled_requests` (#907) 
+- [fix] Dont attempt to parse a nil response when hooking into `:excon` (#916)
 
 ## 6.0.0 (May 28, 2020)
 [Full Changelog](https://github.com/vcr/vcr/compare/v5.1.0...v6.0.0)

lib/vcr/middleware/excon.rb

@@ -74,7 +74,7 @@ def before_request(request_params)
         def after_request(response)
           vcr_response = vcr_response_for(response)
 
-          if should_record?
+          if vcr_response && should_record?
             VCR.record_http_interaction(VCR::HTTPInteraction.new(vcr_request, vcr_response))
           end
 

spec/lib/vcr/library_hooks/excon_spec.rb

@@ -45,6 +45,26 @@ def make_request
     end
   end
 
+  context "when Excon raises an internal error before body is processed" do
+    let(:excon) { ::Excon.new('https://expired.badssl.com') }
+    let(:ssl_error) { OpenSSL::SSL::SSLError.new("SSL_connect returned=1 errno=0 state=error: certificate verify failed (certificate has expired)") }
+
+    before do
+      allow(excon).to receive(:socket) { raise ssl_error }
+    end
+
+    def make_request
+      VCR.use_cassette('with_errors', :record => :once) do
+        excon.request(method: :get, :expects => [200])
+      end
+    end
+
+    it 'raises SSL errors and does not try to record a cassette' do
+      expect(VCR).to_not receive(:record_http_interaction)
+      expect { make_request }.to raise_error(Excon::Error::Certificate)
+    end
+  end
+
   include_examples "Excon streaming"
 
   context 'when Excon raises an error due to an unexpected response status' do