diff --git a/.circleci/config.yml b/.circleci/config.yml
index efacf47f1..6484d4458 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -20,48 +20,48 @@ commands:
   add-github-auth:
     steps:
       - run: git config --global url."https://moleculacorp:${GITHUB_PERSONAL_ACCESS_TOKEN}@github.com".insteadOf "https://github.com"
+  restore-mod-cache:
+    steps:
+      - restore_cache:
+          key: mod-cache-{{ checksum "go.sum" }}
+  save-mod-cache:
+    steps:
+      - save_cache:
+          key: mod-cache-{{ checksum "go.sum" }}
+          paths:
+            - /go/pkg/mod/
+  checkout-plus:
+    steps:
+      - add-github-auth
+      - checkout
+      - restore-mod-cache
 
 jobs:
   setup:
     executor:
       name: golang
     steps:
-      - add-github-auth
-      - checkout
-      - restore_cache:
-          keys:
-            - mod-cache-{{ checksum "go.sum" }}
-      - run: "go mod download"
-      - save_cache:
-          key: mod-cache-{{ checksum "go.sum" }}
-          paths:
-            - /go/pkg/mod/
-      - persist_to_workspace:
-          root: .
-          paths: "*"
+      - checkout-plus
+      - run: go mod download
+      - save-mod-cache
   check-license-headers:
     executor:
       name: golang
     steps:
-      - attach_workspace:
-          at: .
+      - checkout-plus
       - run: make check-license-headers
   linter:
     executor:
       name: golang
     steps:
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - run: curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sudo sh -s -- -b /usr/local/bin v1.23.8
       - run: make golangci-lint
   test-build-arm:
     executor:
       name: golang
     steps:
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - run: make build GOOS=linux GOARCH=arm GOARM=5
       - run: make build GOOS=linux GOARCH=arm GOARM=6
       - run: make build GOOS=linux GOARCH=arm GOARM=7
@@ -91,9 +91,7 @@ jobs:
       version: << parameters.golang_version >>
       resource_class: << parameters.resource_class >>
     steps:
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - run: sudo apt-get install lsof
       - run:
           command: make << parameters.test_make_target >> SHARD_WIDTH=<< parameters.shard_width >> GOARCH=<< parameters.goarch >>
@@ -102,18 +100,14 @@ jobs:
     executor:
       name: golang
     steps:
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - setup_remote_docker
       - run: make clustertests-build
   prerelease:
     executor:
       name: golang
     steps:
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - run: make prerelease
       - store_artifacts:
           path: build
@@ -124,6 +118,7 @@ jobs:
     executor:
       name: golang
     steps:
+      - checkout-plus
       - attach_workspace:
           at: .
       - run: make release
@@ -136,6 +131,7 @@ jobs:
     docker:
       - image: circleci/python:2.7-jessie
     steps:
+      - checkout-plus
       - attach_workspace:
           at: .
       - run: sudo pip install awscli
@@ -144,10 +140,7 @@ jobs:
     executor:
       name: golang
     steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - setup_remote_docker
       - run: make docker
       - run: docker login -u $DOCKER_USER -p $DOCKER_PASS
@@ -156,10 +149,7 @@ jobs:
     executor:
       name: golang
     steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - add-github-auth
+      - checkout-plus
       - setup_remote_docker
       - run: make docker
       - run: docker login -u $DOCKER_USER -p $DOCKER_PASS
@@ -170,6 +160,7 @@ workflows:
   build:
     jobs:
       - setup:
+          context: molecula
           filters:
             tags:
               only: /^v.*/
diff --git a/executor.go b/executor.go
index f2dd49fcb..c54ad6d8d 100644
--- a/executor.go
+++ b/executor.go
@@ -3125,11 +3125,19 @@ func (e *executor) executeSetRow(ctx context.Context, indexName string, c *pql.C
 
 	// Merge returned results at coordinating node.
 	reduceFn := func(ctx context.Context, prev, v interface{}) interface{} {
-		val := v.(bool)
-		if prev == nil {
+		val, ok := v.(bool)
+		if !ok {
+			return errors.Errorf("executeSetRow.reduceFn: val is non-bool (%+v)", v)
+		}
+		if val {
 			return val
 		}
-		return val || prev.(bool)
+
+		pval, ok := prev.(bool)
+		if !ok {
+			return errors.Errorf("executeSetRow.reduceFn: prev is non-bool (%+v)", prev)
+		}
+		return pval
 	}
 
 	result, err := e.mapReduce(ctx, indexName, shards, c, opt, mapFn, reduceFn)