feat: implement local contexts (#541)

* Implement local contexts

* Add extra guards in case @local_context is nil

lib/honeybadger/agent.rb

@@ -259,8 +259,8 @@ def track_deployment(environment: nil, revision: nil, local_username: nil, repos
     #   (optional).
     #
     # @return [self] so that method calls can be chained.
-    def context(context = nil)
-      context_manager.set_context(context) unless context.nil?
+    def context(context = nil, &block)
+      context_manager.set_context(context, &block) unless context.nil?
       self
     end
 

lib/honeybadger/context_manager.rb

@@ -21,15 +21,36 @@ def clear!
     # Internal helpers
 
 
-    def set_context(hash)
+    def set_context(hash, &block)
+      local = block_given?
       @mutex.synchronize do
-        @context ||= {}
-        @context.update(Context(hash))
+        @global_context ||= {}
+        @local_context ||= []
+
+        new_context = Context(hash)
+
+        if local
+          @local_context << new_context
+        else
+          @global_context.update(new_context)
+        end
+      end
+
+      if local
+        begin
+          yield
+        ensure
+          @mutex.synchronize { @local_context&.pop }
+        end
       end
     end
 
     def get_context
-      @mutex.synchronize { @context }
+      @mutex.synchronize do
+        return @global_context unless @local_context
+
+        @global_context.merge(@local_context.inject({}, :merge))
+      end
     end
 
     def set_rack_env(env)
@@ -46,10 +67,10 @@ def get_rack_env
 
     def _initialize
       @mutex.synchronize do
-        @context = nil
+        @global_context = nil
+        @local_context = nil
         @rack_env = nil
       end
     end
-
   end
 end

spec/unit/honeybadger_spec.rb

@@ -50,6 +50,7 @@
     let(:c) { {foo: :bar} }
 
     before { described_class.context(c) }
+    after { described_class.context.clear! }
 
     it "sets the context" do
       described_class.context(c)
@@ -67,6 +68,48 @@
     it "clears the context" do
       expect { described_class.context.clear! }.to change { described_class.get_context }.from(c).to(nil)
     end
+
+    context 'with local context' do
+      it 'merges local context' do
+        allow(described_class).to receive(:get_context).and_call_original
+
+        described_class.context({ bar: :baz }) do
+          described_class.context({ bar: :qux }) do
+            expect(described_class.get_context).to eq({ foo: :bar, bar: :qux })
+          end
+          expect(described_class.get_context).to eq({ foo: :bar, bar: :baz })
+        end
+
+        expect(described_class).to have_received(:get_context).at_least(:twice)
+      end
+
+      it 'clears local context' do
+        allow(described_class).to receive(:get_context).and_call_original
+
+        described_class.context({ bar: :baz }) do
+          expect(described_class.get_context).to eq({ foo: :bar, bar: :baz })
+        end
+        expect(described_class.get_context).to eq({ foo: :bar })
+
+        expect(described_class).to have_received(:get_context).at_least(:twice)
+      end
+
+      it 'tracks local context correctly' do
+        allow(described_class).to receive(:get_context).and_call_original
+
+        begin
+          described_class.context({ bar: :qux }) do
+            described_class.context({ baz: :qux })
+
+            raise 'exception'
+          end
+        rescue StandardError
+          # noop
+        end
+
+        expect(described_class.get_context).to eq({ foo: :bar, baz: :qux })
+      end
+    end
   end
 
   describe "#notify" do