RUBY-1587 Properly handle error labels sent by server (#1163)

Author: saghm

lib/mongo/error.rb

@@ -96,7 +96,7 @@ def change_stream_resumable?
     TRANSIENT_TRANSACTION_ERROR_LABEL = 'TransientTransactionError'.freeze
 
     def initialize(msg = nil)
-      @labels = []
+      @labels ||= []
       super(msg)
     end
 
@@ -114,6 +114,18 @@ def label?(label)
       @labels.include?(label)
     end
 
+    # Gets the set of labels associated with the error.
+    #
+    # @example
+    #   error.labels
+    #
+    # @return [ Array ] The set of labels.
+    #
+    # @since 2.7.0
+    def labels
+      @labels.dup
+    end
+
     private
 
     def add_label(label)

lib/mongo/error/operation_failure.rb

@@ -181,6 +181,7 @@ def initialize(message = nil, result = nil, options = {})
         @result = result
         @code = options[:code]
         @code_name = options[:code_name]
+        @labels = options[:labels]
         super(message)
       end
     end

lib/mongo/error/parser.rb

@@ -62,6 +62,10 @@ class Parser
       # @since 2.6.0
       attr_reader :code_name
 
+      # @return [ Array ] labels The set of labels associated with the error.
+      # @since 2.7.0
+      attr_reader :labels
+
       # Create the new parser with the returned document.
       #
       # @example Create the new parser.
@@ -88,6 +92,7 @@ def parse!
                      document[WRITE_CONCERN_ERROR]) if document[WRITE_CONCERN_ERROR]
         parse_flag(@message)
         parse_code
+        parse_labels
       end
 
       def parse_single(message, key, doc = document)
@@ -147,6 +152,10 @@ def parse_code
           end
         end
       end
+
+      def parse_labels
+        @labels = document['errorLabels'] || []
+      end
     end
   end
 end

lib/mongo/operation/result.rb

@@ -267,7 +267,7 @@ def raise_operation_failure
         raise Error::OperationFailure.new(
           parser.message,
           self,
-          :code => parser.code, :code_name => parser.code_name)
+          :code => parser.code, :code_name => parser.code_name, :labels => parser.labels)
       end
       private :raise_operation_failure
 
@@ -312,6 +312,18 @@ def cluster_time
         first_document && first_document[CLUSTER_TIME]
       end
 
+      # Gets the set of error labels associated with the result.
+      #
+      # @example Get the labels.
+      #   result.labels
+      #
+      # @return [ Array ] labels The set of labels.
+      #
+      # @since 2.7.0
+      def labels
+        @labels ||= parser.labels
+      end
+
       private
 
       def aggregate_returned_count

spec/mongo/error/operation_failure_spec.rb

@@ -149,4 +149,74 @@
       end
     end
   end
+
+  describe '#labels' do
+
+    context 'when the result is nil' do
+
+      subject do
+        described_class.new('not master (10107)', nil,
+          :code => 10107, :code_name => 'NotMaster')
+      end
+
+      it 'has no labels' do
+        expect(subject.labels).to eq([])
+      end
+    end
+
+    context 'when the result is not nil' do
+
+      let(:reply_document) do
+        {
+            'code' => 251,
+            'codeName' => 'NoSuchTransaction',
+            'errorLabels' => labels,
+        }
+      end
+
+      let(:reply) do
+        Mongo::Protocol::Reply.new.tap do |r|
+          # Because this was not created by Mongo::Protocol::Reply::deserialize, we need to manually
+          # initialize the fields.
+          r.instance_variable_set(:@documents, [reply_document])
+          r.instance_variable_set(:@flags, [])
+        end
+      end
+
+      let(:result) do
+        Mongo::Operation::Result.new(reply)
+      end
+
+      subject do
+        begin
+          result.send(:raise_operation_failure)
+        rescue => e
+          e
+        end
+      end
+
+      context 'when the error has no labels' do
+
+        let(:labels) do
+          []
+        end
+
+        it 'has the correct labels' do
+          expect(subject.labels).to eq(labels)
+        end
+      end
+
+
+      context 'when the error has labels' do
+
+        let(:labels) do
+          [ Mongo::Error::TRANSIENT_TRANSACTION_ERROR_LABEL ]
+        end
+
+        it 'has the correct labels' do
+          expect(subject.labels).to eq(labels)
+        end
+      end
+    end
+  end
 end

spec/mongo/error/parser_spec.rb

@@ -95,7 +95,7 @@
       end
     end
   end
-  
+
   describe '#code' do
     let(:parser) do
       described_class.new(document)
@@ -105,7 +105,7 @@
       let(:document) do
         { 'ok' => 0, 'errmsg' => 'not master', 'code' => 10107, 'codeName' => 'NotMaster' }
       end
-      
+
       it 'returns the code' do
         expect(parser.code).to eq(10107)
       end
@@ -115,7 +115,7 @@
       let(:document) do
         { 'ok' => 0, 'errmsg' => 'not master' }
       end
-      
+
       it 'returns nil' do
         expect(parser.code).to eq(nil)
       end
@@ -143,7 +143,7 @@
       end
     end
   end
-  
+
   describe '#code_name' do
     let(:parser) do
       described_class.new(document)
@@ -153,7 +153,7 @@
       let(:document) do
         { 'ok' => 0, 'errmsg' => 'not master', 'code' => 10107, 'codeName' => 'NotMaster' }
       end
-      
+
       it 'returns the code name' do
         expect(parser.code_name).to eq('NotMaster')
       end
@@ -163,7 +163,7 @@
       let(:document) do
         { 'ok' => 0, 'errmsg' => 'not master' }
       end
-      
+
       it 'returns nil' do
         expect(parser.code_name).to eq(nil)
       end
@@ -192,7 +192,7 @@
       end
     end
   end
-  
+
   describe '#document' do
     let(:parser) do
       described_class.new(document)
@@ -201,12 +201,12 @@
     let(:document) do
       { 'ok' => 0, 'errmsg' => 'not master', 'code' => 10107, 'codeName' => 'NotMaster' }
     end
-    
+
     it 'returns the document' do
       expect(parser.document).to eq(document)
     end
   end
-  
+
   describe '#replies' do
     let(:parser) do
       described_class.new(document)
@@ -216,10 +216,44 @@
       let(:document) do
         { 'ok' => 0, 'errmsg' => 'not master', 'code' => 10107, 'codeName' => 'NotMaster' }
       end
-      
+
       it 'returns nil' do
         expect(parser.replies).to eq(nil)
       end
     end
   end
+
+  describe '#labels' do
+    let(:parser) do
+      described_class.new(document)
+    end
+
+    let(:document) do
+      {
+        'code' => 251,
+        'codeName' => 'NoSuchTransaction',
+        'errorLabels' => labels,
+      }
+    end
+
+    context 'when there are no labels' do
+      let(:labels) do
+        []
+      end
+
+      it 'has the correct labels' do
+        expect(parser.labels).to eq(labels)
+      end
+    end
+
+    context 'when there are labels' do
+      let(:labels) do
+        [ Mongo::Error::TRANSIENT_TRANSACTION_ERROR_LABEL ]
+      end
+
+      it 'has the correct labels' do
+        expect(parser.labels).to eq(labels)
+      end
+    end
+  end
 end

spec/support/transactions/operation.rb

@@ -114,12 +114,12 @@ def execute(collection, session0, session1)
         {
           'errorCodeName' => err_doc['codeName'] || err_doc['writeConcernError']['codeName'],
           'errorContains' => e.message,
-          'errorLabels' => (e.instance_variable_get(:@labels) || []) + (err_doc['errorLabels'] || [])
+          'errorLabels' => e.labels
         }
       rescue Mongo::Error => e
         {
           'errorContains' => e.message,
-          'errorLabels' => e.instance_variable_get(:@labels) || []
+          'errorLabels' => e.labels
         }
       end