From a4566a399547d7419792233e6e3106da148c84ee Mon Sep 17 00:00:00 2001
From: Brad Lugo <brad@bradlugo.com>
Date: Sat, 30 Jul 2022 12:12:32 -0700
Subject: [PATCH] fix!: Unlock doesn't release connection

BREAKING CHANGE: Changes the Locker interface and requires the user
to call Close instead of Unlock to release the connection.
---
 README.md    |  2 +-
 go.mod       |  2 +-
 lock.go      | 12 +++++++-----
 lock_test.go |  8 ++++++++
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 6ec8ea9..4e761e1 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ import (
 	"log"
 	"os"
 
-	pglock "github.com/allisson/go-pglock/v2"
+	"github.com/allisson/go-pglock/v3"
 	_ "github.com/lib/pq"
 )
 
diff --git a/go.mod b/go.mod
index fb63985..6c898f8 100644
--- a/go.mod
+++ b/go.mod
@@ -1,4 +1,4 @@
-module github.com/allisson/go-pglock/v2
+module github.com/allisson/go-pglock/v3
 
 go 1.15
 
diff --git a/lock.go b/lock.go
index 951938c..b6494d5 100644
--- a/lock.go
+++ b/lock.go
@@ -10,6 +10,7 @@ type Locker interface {
 	Lock(ctx context.Context) (bool, error)
 	WaitAndLock(ctx context.Context) error
 	Unlock(ctx context.Context) error
+	Close() error
 }
 
 // Lock implements the Locker interface.
@@ -37,14 +38,15 @@ func (l *Lock) WaitAndLock(ctx context.Context) error {
 	return err
 }
 
-// Unlock releases the lock and DB connection.
+// Unlock releases the lock.
 func (l *Lock) Unlock(ctx context.Context) error {
 	sqlQuery := "SELECT pg_advisory_unlock($1)"
 	_, err := l.conn.ExecContext(ctx, sqlQuery, l.id)
-	if err != nil {
-		return err
-	}
-	// Returns the connection to the connection pool
+	return err
+}
+
+// Close closes the DB connection, consequently releasing all locks.
+func (l *Lock) Close() error {
 	return l.conn.Close()
 }
 
diff --git a/lock_test.go b/lock_test.go
index 081570a..b071f56 100644
--- a/lock_test.go
+++ b/lock_test.go
@@ -47,6 +47,7 @@ func TestNewLock(t *testing.T) {
 	id := int64(10)
 	lock, err := NewLock(context.Background(), id, db)
 	assert.Nil(t, err)
+	defer assert.Nil(t, lock.Close())
 	assert.Equal(t, id, lock.id)
 	assert.NotNil(t, lock.conn)
 }
@@ -63,8 +64,10 @@ func TestLockUnlock(t *testing.T) {
 	id := int64(1)
 	lock1, err := NewLock(ctx, id, db1)
 	assert.Nil(t, err)
+	defer lock1.Close()
 	lock2, err := NewLock(ctx, id, db2)
 	assert.Nil(t, err)
+	defer lock2.Close()
 
 	ok, err := lock1.Lock(ctx)
 	assert.True(t, ok)
@@ -83,6 +86,9 @@ func TestLockUnlock(t *testing.T) {
 
 	err = lock2.Unlock(ctx)
 	assert.Nil(t, err)
+
+	err = lock2.Unlock(ctx)
+	assert.Nil(t, err)
 }
 
 func TestWaitAndLock(t *testing.T) {
@@ -98,8 +104,10 @@ func TestWaitAndLock(t *testing.T) {
 	id := int64(1)
 	lock1, err := NewLock(ctx, id, db1)
 	assert.Nil(t, err)
+	defer lock1.Close()
 	lock2, err := NewLock(ctx, id, db2)
 	assert.Nil(t, err)
+	defer lock2.Close()
 
 	start := time.Now()
 	wg.Add(1)