From 007d25d608ebcb020c1e901df6f803aba7361295 Mon Sep 17 00:00:00 2001
From: Benjamin Pannell <benjamin@pannell.dev>
Date: Wed, 25 Sep 2019 21:44:30 +0100
Subject: [PATCH 1/3] fix: Correct a potential race condition when serializing
 breadcrumbs

---
 breadcrumbs.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/breadcrumbs.go b/breadcrumbs.go
index b966e5a..e60057f 100644
--- a/breadcrumbs.go
+++ b/breadcrumbs.go
@@ -66,7 +66,7 @@ type breadcrumbsList struct {
 	Head   *breadcrumbListNode
 	Tail   *breadcrumbListNode
 	Length int
-	mutex  sync.Mutex
+	mutex  sync.RWMutex
 }
 
 func (l *breadcrumbsList) Class() string {
@@ -82,7 +82,7 @@ func (l *breadcrumbsList) WithSize(length int) BreadcrumbsList {
 	for l.Length > l.MaxLength {
 		if l.Head == nil {
 			break
-		}
+	}
 		l.Head = l.Head.Next
 		l.Length--
 	}
@@ -157,6 +157,9 @@ func (l *breadcrumbsList) append(b Breadcrumb) {
 }
 
 func (l *breadcrumbsList) list() []Breadcrumb {
+	l.mutex.RLock()
+	defer l.mutex.RUnlock()
+
 	current := l.Head
 	out := []Breadcrumb{}
 	for current != nil {

From 67286c02ba36bb83c6932c233ae9f1174f847976 Mon Sep 17 00:00:00 2001
From: Benjamin Pannell <benjamin@pannell.dev>
Date: Wed, 25 Sep 2019 21:45:05 +0100
Subject: [PATCH 2/3] fix: Correct an issue with the use of
 breadcrumbs.WithSize(0) to clear the buffer

---
 breadcrumbs.go | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/breadcrumbs.go b/breadcrumbs.go
index e60057f..bf330f0 100644
--- a/breadcrumbs.go
+++ b/breadcrumbs.go
@@ -79,10 +79,13 @@ func (l *breadcrumbsList) WithSize(length int) BreadcrumbsList {
 
 	l.MaxLength = length
 
-	for l.Length > l.MaxLength {
-		if l.Head == nil {
-			break
+	if length == 0 {
+		l.Head = nil
+		l.Tail = nil
+		l.Length = 0
 	}
+
+	for l.Length > l.MaxLength && l.Head != nil {
 		l.Head = l.Head.Next
 		l.Length--
 	}
@@ -147,10 +150,7 @@ func (l *breadcrumbsList) append(b Breadcrumb) {
 	l.Tail = n
 	l.Length++
 
-	for l.Length > l.MaxLength {
-		if l.Head == nil {
-			break
-		}
+	for l.Length > l.MaxLength && l.Head != nil {
 		l.Head = l.Head.Next
 		l.Length--
 	}

From 7a2d535939376ef0adf311effead922e97ab2175 Mon Sep 17 00:00:00 2001
From: Benjamin Pannell <benjamin@pannell.dev>
Date: Wed, 25 Sep 2019 21:57:05 +0100
Subject: [PATCH 3/3] test: Add tests to ensure that the new WithSize(0) works

---
 breadcrumbs_test.go | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/breadcrumbs_test.go b/breadcrumbs_test.go
index b5b649c..c453397 100644
--- a/breadcrumbs_test.go
+++ b/breadcrumbs_test.go
@@ -214,6 +214,21 @@ func TestBreadcrumbs(t *testing.T) {
 						"index": 2,
 					})
 				})
+
+				Convey("Should empty the list if the size is set to 0", func() {
+					var b Breadcrumb
+					for i := 0; i < 3; i++ {
+						b = l.NewDefault(map[string]interface{}{
+							"index": i,
+						})
+						So(b, ShouldNotBeNil)
+					}
+
+					l.WithSize(0).WithSize(3)
+					So(ll.Length, ShouldEqual, 0)
+					So(ll.Head, ShouldBeNil)
+					So(ll.Tail, ShouldBeNil)
+				})
 			})
 
 			Convey("append()", func() {