From 96caa6f24211e90ce623de54a6d8a42ba32ba6fb Mon Sep 17 00:00:00 2001
From: Andras Banki-Horvath <bhandras@gmail.com>
Date: Wed, 16 Jun 2021 16:56:38 +0200
Subject: [PATCH] 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                 |  8 ++++++++
 kvdb/etcd/debug.go            |  8 ++++++++
 kvdb/etcd/nodebug.go          |  8 ++++++++
 kvdb/etcd/readwrite_bucket.go | 29 +++++++++++++++++++++++------
 kvdb/etcd_test.go             | 10 ++++++++--
 kvdb/nodebug.go               |  8 ++++++++
 6 files changed, 63 insertions(+), 8 deletions(-)
 create mode 100644 kvdb/debug.go
 create mode 100644 kvdb/etcd/debug.go
 create mode 100644 kvdb/etcd/nodebug.go
 create mode 100644 kvdb/nodebug.go

diff --git a/kvdb/debug.go b/kvdb/debug.go
new file mode 100644
index 00000000..07874bea
--- /dev/null
+++ b/kvdb/debug.go
@@ -0,0 +1,8 @@
+// +build dev
+
+package kvdb
+
+const (
+	// Switch on extra debug code.
+	etcdDebug = true
+)
diff --git a/kvdb/etcd/debug.go b/kvdb/etcd/debug.go
new file mode 100644
index 00000000..5b67b0bb
--- /dev/null
+++ b/kvdb/etcd/debug.go
@@ -0,0 +1,8 @@
+// +build dev
+
+package etcd
+
+const (
+	// Switch on extra debug code.
+	etcdDebug = true
+)
diff --git a/kvdb/etcd/nodebug.go b/kvdb/etcd/nodebug.go
new file mode 100644
index 00000000..9494f8cc
--- /dev/null
+++ b/kvdb/etcd/nodebug.go
@@ -0,0 +1,8 @@
+// +build !dev
+
+package etcd
+
+const (
+	// Switch off extra debug code.
+	etcdDebug = false
+)
diff --git a/kvdb/etcd/readwrite_bucket.go b/kvdb/etcd/readwrite_bucket.go
index 0be2f88e..7591d7f9 100644
--- a/kvdb/etcd/readwrite_bucket.go
+++ b/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 != nil {
+	if err := b.assertNoBucket(key); 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))
 
diff --git a/kvdb/etcd_test.go b/kvdb/etcd_test.go
index fc81bb93..6d96d284 100644
--- a/kvdb/etcd_test.go
+++ b/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
 	}{
@@ -103,8 +104,9 @@ func TestEtcd(t *testing.T) {
 			test: testBucketSequence,
 		},
 		{
-			name: "key clash",
-			test: testKeyClash,
+			name:      "key clash",
+			debugOnly: true,
+			test:      testKeyClash,
 			expectedDb: map[string]string{
 				bkey("apple"):           bval("apple"),
 				bkey("apple", "banana"): bval("apple", "banana"),
@@ -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()
 
diff --git a/kvdb/nodebug.go b/kvdb/nodebug.go
new file mode 100644
index 00000000..76225182
--- /dev/null
+++ b/kvdb/nodebug.go
@@ -0,0 +1,8 @@
+// +build !dev
+
+package kvdb
+
+const (
+	// Switch off extra debug code.
+	etcdDebug = false
+)