Make build-fuzz work again, test it on CI

.buildkite/pipeline.yml

@@ -176,6 +176,19 @@ steps:
   # to finish running in parallel before continuing.
   - wait
 
+  ###################################################
+  # Test that build-fuzz still works (only on master)
+  ###################################################
+  - label: Test fuzz builds
+    branches: master
+    command:
+      - . .buildkite/scripts/skip_if_only_docs_changes.sh
+      # TODO: Consider making this a part of the development Docker image.
+      - go get -u github.com/dvyukov/go-fuzz/go-fuzz github.com/dvyukov/go-fuzz/go-fuzz-build
+      - make -C go build-fuzz
+    plugins:
+      <<: *docker_plugin
+
   #####################################
   # Test jobs requiring build artifacts
   #####################################

.changelog/2695.internal.md

@@ -0,0 +1 @@
+Make build-fuzz work again, test it on CI

go/consensus/tendermint/abci/mux_mock.go

@@ -4,6 +4,8 @@ package abci
 
 import (
 	"context"
+
+	upgrade "github.com/oasislabs/oasis-core/go/upgrade/api"
 )
 
 // MockABCIMux exports some of the muxer's internal methods for testing use.
@@ -22,8 +24,8 @@ func (mux *MockABCIMux) MockClose() {
 }
 
 // NewMockMux creates a new ABCI mux suitable for testing.
-func NewMockMux(ctx context.Context, cfg *ApplicationConfig) (*MockABCIMux, error) {
-	mux, err := newABCIMux(ctx, cfg)
+func NewMockMux(ctx context.Context, upgrader upgrade.Backend, cfg *ApplicationConfig) (*MockABCIMux, error) {
+	mux, err := newABCIMux(ctx, upgrader, cfg)
 	if err != nil {
 		return nil, err
 	}

go/consensus/tendermint/apps/staking/proposing_rewards.go

@@ -41,7 +41,8 @@ func (app *stakingApplication) rewardBlockProposing(ctx *abci.Context, stakeStat
 	if err != nil {
 		return fmt.Errorf("app state getting current epoch: %w", err)
 	}
-	if epoch == epochtime.EpochInvalid {
+	invalidEpoch := epochtime.EpochInvalid // Workaround for incorrect go-fuzz instrumentation.
+	if epoch == invalidEpoch {
 		ctx.Logger().Info("rewardBlockProposing: this block does not belong to an epoch. no block proposing reward")
 		return nil
 	}

go/consensus/tendermint/fuzz/fuzz.go

@@ -16,6 +16,7 @@ import (
 	"github.com/oasislabs/oasis-core/go/consensus/tendermint/apps/epochtime_mock"
 	registryApp "github.com/oasislabs/oasis-core/go/consensus/tendermint/apps/registry"
 	stakingApp "github.com/oasislabs/oasis-core/go/consensus/tendermint/apps/staking"
+	"github.com/oasislabs/oasis-core/go/upgrade"
 )
 
 var (
@@ -53,7 +54,7 @@ func Fuzz(data []byte) int {
 	}
 
 	// The muxer will start with the previous state, if it exists (the state database isn't cleared).
-	muxer, _ := abci.NewMockMux(ctx, appConfig)
+	muxer, _ := abci.NewMockMux(ctx, upgrade.NewDummyUpgradeManager(), appConfig)
 	defer muxer.MockClose()
 
 	for _, app := range FuzzableApps {

go/storage/fuzz/fuzz.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"io/ioutil"
 
+	"github.com/oasislabs/oasis-core/go/common"
 	"github.com/oasislabs/oasis-core/go/common/crypto/signature"
 	"github.com/oasislabs/oasis-core/go/common/crypto/signature/signers/file"
 	commonFuzz "github.com/oasislabs/oasis-core/go/common/fuzz"
@@ -40,7 +41,7 @@ func init() {
 	}
 
 	// Create the storage backend service.
-	storageBackend, err = storage.New(context.Background(), localDB, identity, nil, nil)
+	storageBackend, err = storage.New(context.Background(), localDB, common.Namespace{}, identity, nil, nil)
 	if err != nil {
 		panic(err)
 	}

go/storage/fuzz/gencorpus/main.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io/ioutil"
 
+	"github.com/oasislabs/oasis-core/go/common"
 	commonFuzz "github.com/oasislabs/oasis-core/go/common/fuzz"
 	"github.com/oasislabs/oasis-core/go/common/identity"
 	"github.com/oasislabs/oasis-core/go/storage"
@@ -19,7 +20,7 @@ const (
 )
 
 func main() {
-	storage, err := storage.New(context.Background(), "/tmp/oasis-node-fuzz-storage", &identity.Identity{}, nil, nil)
+	storage, err := storage.New(context.Background(), "/tmp/oasis-node-fuzz-storage", common.Namespace{}, &identity.Identity{}, nil, nil)
 	if err != nil {
 		panic(err)
 	}