diff --git a/go.mod b/go.mod
index 97dbf422f3..2e62168b15 100644
--- a/go.mod
+++ b/go.mod
@@ -32,4 +32,4 @@ replace (
 	k8s.io/code-generator => k8s.io/code-generator v0.16.4
 )
 
-go 1.13
+go 1.14
diff --git a/hack/build.sh b/hack/build.sh
index 214d2aa54e..7dc3e43d0c 100755
--- a/hack/build.sh
+++ b/hack/build.sh
@@ -16,6 +16,9 @@
 
 set -o pipefail
 
+[[ ! -v REPO_ROOT_DIR ]] && REPO_ROOT_DIR="$(git rev-parse --show-toplevel)"
+readonly REPO_ROOT_DIR
+
 source_dirs="cmd pkg test lib"
 
 # Store for later
@@ -110,21 +113,38 @@ go_fmt() {
   find $(echo $source_dirs) -name "*.go" -print0 | xargs -0 gofmt -s -w
 }
 
+# Run a go tool, installing it first if necessary.
+# Parameters: $1 - tool package/dir for go get/install.
+#             $2 - tool to run.
+#             $3..$n - parameters passed to the tool.
+run_go_tool() {
+  local tool=$2
+  local install_failed=0
+  if [[ -z "$(which ${tool})" ]]; then
+    local action=get
+    [[ $1 =~ ^[\./].* ]] && action=install
+    # Avoid running `go get` from root dir of the repository, as it can change go.sum and go.mod files.
+    # See discussions in https://github.com/golang/go/issues/27643.
+    if [[ ${action} == "get" && $(pwd) == "${REPO_ROOT_DIR}" ]]; then
+      local temp_dir="$(mktemp -d)"
+      # Swallow the output as we are returning the stdout in the end.
+      pushd "${temp_dir}" > /dev/null 2>&1
+      GOFLAGS="" go ${action} "$1" || install_failed=1
+      popd > /dev/null 2>&1
+    else
+      GOFLAGS="" go ${action} "$1" || install_failed=1
+    fi
+  fi
+  (( install_failed )) && return ${install_failed}
+  shift 2
+  ${tool} "$@"
+}
+
+
 source_format() {
   set +e
-  which goimports >/dev/null 2>&1
-  if [ $? -ne 0 ]; then
-     echo "✋ No 'goimports' found. Please use"
-     echo "✋   go install golang.org/x/tools/cmd/goimports"
-     echo "✋ to enable import cleanup. Import cleanup skipped."
-
-     # Run go fmt instead
-     go_fmt
-  else
-     echo "🧽 ${X}Format"
-     goimports -w $(echo $source_dirs)
-     find $(echo $source_dirs) -name "*.go" -print0 | xargs -0 gofmt -s -w
-  fi
+  run_go_tool golang.org/x/tools/cmd/goimports goimports -w $(echo $source_dirs)
+  find $(echo $source_dirs) -name "*.go" -print0 | xargs -0 gofmt -s -w
   set -e
 }
 
diff --git a/hack/verify-codegen.sh b/hack/verify-codegen.sh
index ee9036a308..511cabc01e 100755
--- a/hack/verify-codegen.sh
+++ b/hack/verify-codegen.sh
@@ -20,9 +20,6 @@ set -o pipefail
 
 source $(dirname $0)/../scripts/test-infra/library.sh
 
-# Needed later
-go install golang.org/x/tools/cmd/goimports
-
 "${REPO_ROOT_DIR}"/hack/build.sh --codegen
 if output="$(git status --porcelain)" && [ -z "$output" ]; then
   echo "${REPO_ROOT_DIR} is up to date."
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 54c326ad61..3cb3eec76e 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -83,6 +83,7 @@ github.com/mailru/easyjson/buffer
 github.com/mailru/easyjson/jlexer
 github.com/mailru/easyjson/jwriter
 # github.com/mitchellh/go-homedir v1.1.0
+## explicit
 github.com/mitchellh/go-homedir
 # github.com/mitchellh/mapstructure v1.1.2
 github.com/mitchellh/mapstructure
@@ -108,13 +109,16 @@ github.com/spf13/afero/mem
 # github.com/spf13/cast v1.3.1
 github.com/spf13/cast
 # github.com/spf13/cobra v0.0.6 => github.com/chmouel/cobra v0.0.0-20191021105835-a78788917390
+## explicit
 github.com/spf13/cobra
 github.com/spf13/cobra/doc
 # github.com/spf13/jwalterweatherman v1.1.0
 github.com/spf13/jwalterweatherman
 # github.com/spf13/pflag v1.0.5
+## explicit
 github.com/spf13/pflag
 # github.com/spf13/viper v1.6.2
+## explicit
 github.com/spf13/viper
 # github.com/subosito/gotenv v1.2.0
 github.com/subosito/gotenv
@@ -130,6 +134,7 @@ go.uber.org/zap/internal/color
 go.uber.org/zap/internal/exit
 go.uber.org/zap/zapcore
 # golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073
+## explicit
 golang.org/x/crypto/ssh/terminal
 # golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e
 golang.org/x/net/context
@@ -184,12 +189,14 @@ gopkg.in/ini.v1
 # gopkg.in/yaml.v2 v2.3.0
 gopkg.in/yaml.v2
 # gotest.tools v2.2.0+incompatible
+## explicit
 gotest.tools/assert
 gotest.tools/assert/cmp
 gotest.tools/internal/difflib
 gotest.tools/internal/format
 gotest.tools/internal/source
 # k8s.io/api v0.17.6 => k8s.io/api v0.16.4
+## explicit
 k8s.io/api/admissionregistration/v1
 k8s.io/api/admissionregistration/v1beta1
 k8s.io/api/apps/v1
@@ -229,6 +236,7 @@ k8s.io/api/storage/v1
 k8s.io/api/storage/v1alpha1
 k8s.io/api/storage/v1beta1
 # k8s.io/apimachinery v0.17.6 => k8s.io/apimachinery v0.16.4
+## explicit
 k8s.io/apimachinery/pkg/api/apitesting/fuzzer
 k8s.io/apimachinery/pkg/api/equality
 k8s.io/apimachinery/pkg/api/errors
@@ -278,6 +286,7 @@ k8s.io/apimachinery/pkg/watch
 k8s.io/apimachinery/third_party/forked/golang/json
 k8s.io/apimachinery/third_party/forked/golang/reflect
 # k8s.io/cli-runtime v0.17.3 => k8s.io/cli-runtime v0.16.4
+## explicit
 k8s.io/cli-runtime/pkg/genericclioptions
 k8s.io/cli-runtime/pkg/kustomize
 k8s.io/cli-runtime/pkg/kustomize/k8sdeps
@@ -291,6 +300,7 @@ k8s.io/cli-runtime/pkg/kustomize/k8sdeps/validator
 k8s.io/cli-runtime/pkg/printers
 k8s.io/cli-runtime/pkg/resource
 # k8s.io/client-go v11.0.1-0.20190805182717-6502b5e7b1b5+incompatible => k8s.io/client-go v0.16.4
+## explicit
 k8s.io/client-go/discovery
 k8s.io/client-go/discovery/cached/disk
 k8s.io/client-go/dynamic
@@ -462,6 +472,7 @@ k8s.io/utils/buffer
 k8s.io/utils/integer
 k8s.io/utils/trace
 # knative.dev/eventing v0.15.1-0.20200608083719-c024353a712c
+## explicit
 knative.dev/eventing/pkg/apis/config
 knative.dev/eventing/pkg/apis/configs
 knative.dev/eventing/pkg/apis/configs/v1alpha1
@@ -484,6 +495,7 @@ knative.dev/eventing/pkg/client/clientset/versioned/typed/sources/v1alpha2
 knative.dev/eventing/pkg/client/clientset/versioned/typed/sources/v1alpha2/fake
 knative.dev/eventing/pkg/logging
 # knative.dev/pkg v0.0.0-20200606224418-7ed1d4a552bc
+## explicit
 knative.dev/pkg/apis
 knative.dev/pkg/apis/duck
 knative.dev/pkg/apis/duck/v1
@@ -500,6 +512,7 @@ knative.dev/pkg/profiling
 knative.dev/pkg/ptr
 knative.dev/pkg/tracker
 # knative.dev/serving v0.15.1-0.20200608114919-92e849c1db9c
+## explicit
 knative.dev/serving/pkg/apis/autoscaling
 knative.dev/serving/pkg/apis/autoscaling/v1alpha1
 knative.dev/serving/pkg/apis/config
@@ -537,4 +550,12 @@ sigs.k8s.io/kustomize/pkg/transformers/config
 sigs.k8s.io/kustomize/pkg/transformers/config/defaultconfig
 sigs.k8s.io/kustomize/pkg/types
 # sigs.k8s.io/yaml v1.2.0
+## explicit
 sigs.k8s.io/yaml
+# github.com/spf13/cobra => github.com/chmouel/cobra v0.0.0-20191021105835-a78788917390
+# k8s.io/api => k8s.io/api v0.16.4
+# k8s.io/apiextensions-apiserver => k8s.io/apiextensions-apiserver v0.16.4
+# k8s.io/apimachinery => k8s.io/apimachinery v0.16.4
+# k8s.io/cli-runtime => k8s.io/cli-runtime v0.16.4
+# k8s.io/client-go => k8s.io/client-go v0.16.4
+# k8s.io/code-generator => k8s.io/code-generator v0.16.4