From bcc8f03b95c35e8988f90e5fd3b58112fd634016 Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Fri, 11 Apr 2025 16:51:37 -0700
Subject: Fix a bug in PopAll when the queue is full

---
 deque.go      |  9 ++-------
 deque_test.go | 36 +++++++++++++++++++++++++-----------
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/deque.go b/deque.go
index 1208019..d4ef4be 100644
--- a/deque.go
+++ b/deque.go
@@ -182,15 +182,10 @@ func (q *Deque[T]) PopAll() func(func(T) bool) {
 	n := len(q.buf)
 	q.buf = q.buf[:0]
 	return func(yield func(T) bool) {
-		endIdx := q.toPhysicalIdx(n)
-		for i := q.head; ; {
-			if !yield(q.buf[:cap(q.buf)][i]) {
+		for i := range n {
+			if !yield(q.buf[:cap(q.buf)][q.toPhysicalIdx(i)]) {
 				return
 			}
-			i = q.wrapAdd(i, 1)
-			if i == endIdx {
-				break
-			}
 		}
 	}
 }
diff --git a/deque_test.go b/deque_test.go
index 4f298e1..fede96b 100644
--- a/deque_test.go
+++ b/deque_test.go
@@ -260,17 +260,31 @@ func TestReset(t *testing.T) {
 func TestPopAll(t *testing.T) {
 	t.Parallel()
 
-	q := From([]int{1, 2, 3})
-	got := make([]int, 0, q.Len())
-	for x := range q.PopAll() {
-		got = append(got, x)
-	}
-	if got, want := q.Len(), 0; got != want {
-		t.Errorf("Len() = %d, want %d", got, want)
-	}
-	want := []int{1, 2, 3}
-	if !slices.Equal(got, want) {
-		t.Errorf("PopAll() returned values %d, want %d", got, want)
+	for _, tc := range []struct {
+		desc    string
+		content []int
+	}{{
+		desc:    "PopAll",
+		content: []int{1, 2, 3},
+	}, {
+		desc:    "PopAllEmpty",
+		content: make([]int, 0, 3),
+	}} {
+		t.Run(tc.desc, func(t *testing.T) {
+			t.Parallel()
+
+			q := From(tc.content)
+			got := make([]int, 0, q.Len())
+			for x := range q.PopAll() {
+				got = append(got, x)
+			}
+			if got, want := q.Len(), 0; got != want {
+				t.Errorf("Len() = %d, want %d", got, want)
+			}
+			if !slices.Equal(got, tc.content) {
+				t.Errorf("PopAll() returned values %d, want %d", got, tc.content)
+			}
+		})
 	}
 }
 
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