Improve error handling logic and add missing test coverage

lib/faraday/error.rb

@@ -79,26 +79,47 @@ def exc_msg_and_response!(exc, response = nil)
 
     # Pulls out potential parent exception and response hash.
     def exc_msg_and_response(exc, response = nil)
-      if exc.is_a?(Exception)
+      case exc
+      when Exception
         [exc, exc.message, response]
-      elsif exc.is_a?(Hash) || exc.is_a?(Faraday::Env)
-        http_status = exc.fetch(:status)
-
-        request = exc.fetch(:request, nil)
-
-        if request.nil?
-          exception_message = "the server responded with status #{http_status} - method and url are not available " \
-                              'due to include_request: false on Faraday::Response::RaiseError middleware'
-        else
-          exception_message = "the server responded with status #{http_status} for #{request.fetch(:method).upcase} " \
-                              "#{request.fetch(:url)}"
-        end
-
-        [nil, exception_message, exc]
+      when Hash
+        [nil, build_error_message_from_hash(exc), exc]
+      when Faraday::Env
+        [nil, build_error_message_from_env(exc), exc]
       else
         [nil, exc.to_s, response]
       end
     end
+
+    private
+
+    def build_error_message_from_hash(hash)
+      # Be defensive with external Hash objects - they might be missing keys
+      status = hash.fetch(:status, nil)
+      request = hash.fetch(:request, nil)
+
+      return fallback_error_message(status) if request.nil?
+
+      method = request.fetch(:method, nil)
+      url = request.fetch(:url, nil)
+      build_status_error_message(status, method, url)
+    end
+
+    def build_error_message_from_env(env)
+      # Faraday::Env is internal - we can make reasonable assumptions about its structure
+      build_status_error_message(env.status, env.method, env.url)
+    end
+
+    def build_status_error_message(status, method, url)
+      method_str = method ? method.to_s.upcase : ''
+      url_str = url ? url.to_s : ''
+      "the server responded with status #{status} for #{method_str} #{url_str}"
+    end
+
+    def fallback_error_message(status)
+      "the server responded with status #{status} - method and url are not available " \
+        'due to include_request: false on Faraday::Response::RaiseError middleware'
+    end
   end
 
   # Faraday client error class. Represents 4xx status responses.

spec/faraday/error_spec.rb

@@ -89,5 +89,87 @@
       it { expect(subject.response_headers).to eq(headers) }
       it { expect(subject.response_body).to eq(body) }
     end
+
+    context 'with hash missing status key' do
+      let(:exception) { { body: 'error body' } }
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status  - method and url are not available due to include_request: false on Faraday::Response::RaiseError middleware') }
+    end
+
+    context 'with hash with status but missing request data' do
+      let(:exception) { { status: 404, body: 'not found' } } # missing request key
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status 404 - method and url are not available due to include_request: false on Faraday::Response::RaiseError middleware') }
+    end
+
+    context 'with hash with status and request but missing method in request' do
+      let(:exception) { { status: 404, body: 'not found', request: { url: 'http://example.com/test' } } } # missing method
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status 404 for  http://example.com/test') }
+    end
+
+    context 'with hash with status and request but missing url in request' do
+      let(:exception) { { status: 404, body: 'not found', request: { method: :get } } } # missing url
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status 404 for GET ') }
+    end
+
+    context 'with properly formed Faraday::Env' do
+      # This represents the normal case - a well-formed Faraday::Env object
+      # with all the standard properties populated as they would be during
+      # a typical HTTP request/response cycle
+      let(:exception) { Faraday::Env.new }
+
+      before do
+        exception.status = 500
+        exception.method = :post
+        exception.url = URI('https://api.example.com/users')
+        exception.request = Faraday::RequestOptions.new
+        exception.response_headers = { 'content-type' => 'application/json' }
+        exception.response_body = '{"error": "Internal server error"}'
+        exception.request_headers = { 'authorization' => 'Bearer token123' }
+        exception.request_body = '{"name": "John"}'
+      end
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status 500 for POST https://api.example.com/users') }
+    end
+
+    context 'with Faraday::Env missing status key' do
+      let(:exception) { Faraday::Env.new }
+
+      before do
+        exception[:body] = 'error body'
+        # Intentionally not setting status
+      end
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status  for  ') }
+    end
+
+    context 'with Faraday::Env with direct method and url properties' do
+      let(:exception) { Faraday::Env.new }
+
+      before do
+        exception.status = 404
+        exception.method = :get
+        exception.url = URI('http://example.com/test')
+        exception[:body] = 'not found'
+      end
+
+      it { expect(subject.wrapped_exception).to be_nil }
+      it { expect(subject.response).to eq(exception) }
+      it { expect(subject.message).to eq('the server responded with status 404 for GET http://example.com/test') }
+    end
   end
 end