etcd: remove assertion when creating bucket and value with the same key

This commit removes an assertion which is not needed because with etcd
we can safely create keys and values with the same key since they are
stored under different keys in the DB. This saves us one unnecessary Get
on every Put.

kvdb/debug.go

@@ -0,0 +1,8 @@
+// +build dev
+
+package kvdb
+
+const (
+	// Switch on extra debug code.
+	etcdDebug = true
+)

kvdb/etcd/debug.go

@@ -0,0 +1,8 @@
+// +build dev
+
+package etcd
+
+const (
+	// Switch on extra debug code.
+	etcdDebug = true
+)

kvdb/etcd/nodebug.go

@@ -0,0 +1,8 @@
+// +build !dev
+
+package etcd
+
+const (
+	// Switch off extra debug code.
+	etcdDebug = false
+)

kvdb/etcd/readwrite_bucket.go

@@ -118,6 +118,10 @@ func (b *readWriteBucket) NestedReadWriteBucket(key []byte) walletdb.ReadWriteBu
 
 // assertNoValue checks if the value for the passed key exists.
 func (b *readWriteBucket) assertNoValue(key []byte) error {
+	if !etcdDebug {
+		return nil
+	}
+
 	val, err := b.tx.stm.Get(string(makeValueKey(b.id, key)))
 	if err != nil {
 		return err
@@ -130,6 +134,24 @@ func (b *readWriteBucket) assertNoValue(key []byte) error {
 	return nil
 }
 
+// assertNoBucket checks if the bucket for the passed key exists.
+func (b *readWriteBucket) assertNoBucket(key []byte) error {
+	if !etcdDebug {
+		return nil
+	}
+
+	val, err := b.tx.stm.Get(string(makeBucketKey(b.id, key)))
+	if err != nil {
+		return err
+	}
+
+	if val != nil {
+		return walletdb.ErrIncompatibleValue
+	}
+
+	return nil
+}
+
 // CreateBucket creates and returns a new nested bucket with the given
 // key. Returns ErrBucketExists if the bucket already exists,
 // ErrBucketNameRequired if the key is empty, or ErrIncompatibleValue
@@ -272,15 +294,10 @@ func (b *readWriteBucket) Put(key, value []byte) error {
 		return walletdb.ErrKeyRequired
 	}
 
-	val, err := b.tx.stm.Get(string(makeBucketKey(b.id, key)))
+	if err := b.assertNoBucket(key); err != nil {
-	if err != nil {
 		return err
 	}
 
-	if val != nil {
-		return walletdb.ErrIncompatibleValue
-	}
-
 	// Update the transaction with the new value.
 	b.tx.stm.Put(string(makeValueKey(b.id, key)), string(value))
 

kvdb/etcd_test.go

@@ -19,6 +19,7 @@ var (
 func TestEtcd(t *testing.T) {
 	tests := []struct {
 		name       string
+		debugOnly  bool
 		test       func(*testing.T, walletdb.DB)
 		expectedDb map[string]string
 	}{
@@ -104,6 +105,7 @@ func TestEtcd(t *testing.T) {
 		},
 		{
 			name:      "key clash",
+			debugOnly: true,
 			test:      testKeyClash,
 			expectedDb: map[string]string{
 				bkey("apple"):           bval("apple"),
@@ -137,6 +139,10 @@ func TestEtcd(t *testing.T) {
 	for _, test := range tests {
 		test := test
 
+		if test.debugOnly && !etcdDebug {
+			continue
+		}
+
 		t.Run(test.name, func(t *testing.T) {
 			t.Parallel()
 

kvdb/nodebug.go

@@ -0,0 +1,8 @@
+// +build !dev
+
+package kvdb
+
+const (
+	// Switch off extra debug code.
+	etcdDebug = false
+)