From 8d1f78dbd46cc6a5bd97b392c3a24283dcbfc9a6 Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Mon, 13 Nov 2023 18:29:47 +0900
Subject: [PATCH 1/5] fix: implement `Headers#delete` correctly

---
 lib/fetch/headers.js | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/lib/fetch/headers.js b/lib/fetch/headers.js
index f37c5c99e03..cf6f45f267c 100644
--- a/lib/fetch/headers.js
+++ b/lib/fetch/headers.js
@@ -301,14 +301,10 @@ class Headers {
 
     // 6. If this’s header list does not contain name, then
     //    return.
-    if (!this[kHeadersList].contains(name)) {
-      return
-    }
-
     // 7. Delete name from this’s header list.
     // 8. If this’s guard is "request-no-cors", then remove
     //    privileged no-CORS request headers from this.
-    return this[kHeadersList].delete(name)
+    this[kHeadersList].delete(name)
   }
 
   // https://fetch.spec.whatwg.org/#dom-headers-get

From 125611ef31b733745d1ef274e4488e959a4b77f1 Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Mon, 13 Nov 2023 18:38:59 +0900
Subject: [PATCH 2/5] fix: HeadersList

---
 lib/fetch/headers.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/fetch/headers.js b/lib/fetch/headers.js
index cf6f45f267c..29587763bac 100644
--- a/lib/fetch/headers.js
+++ b/lib/fetch/headers.js
@@ -203,7 +203,7 @@ class HeadersList {
       this.cookies = null
     }
 
-    return this[kHeadersMap].delete(name)
+    this[kHeadersMap].delete(name)
   }
 
   // https://fetch.spec.whatwg.org/#concept-header-list-get

From 8f12309417d92ccb35542c3df95a6403c524b10c Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Tue, 14 Nov 2023 03:55:56 +0900
Subject: [PATCH 3/5] test: add

---
 test/fetch/headers.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/test/fetch/headers.js b/test/fetch/headers.js
index c4b4e03d297..d47d6412102 100644
--- a/test/fetch/headers.js
+++ b/test/fetch/headers.js
@@ -160,7 +160,7 @@ tap.test('Headers append', t => {
 })
 
 tap.test('Headers delete', t => {
-  t.plan(3)
+  t.plan(4)
 
   t.test('deletes valid header entry from instance', t => {
     t.plan(3)
@@ -193,6 +193,14 @@ tap.test('Headers delete', t => {
     t.throws(() => headers.delete(), 'throws on missing namee')
     t.throws(() => headers.delete('invalid @ header ? name'), 'throws on invalid name')
   })
+
+  t.test('`Headers#delete` returns undefined', t => {
+    t.plan(2)
+    const headers = new Headers({ test: 'test' })
+
+    t.same(headers.delete('test'), undefined)
+    t.same(headers.delete('test2'), undefined)
+  })
 })
 
 tap.test('Headers get', t => {

From ae27be77b648f196808368bcb5f49d6807d5322d Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Tue, 14 Nov 2023 03:59:38 +0900
Subject: [PATCH 4/5] test: add comment

---
 test/fetch/headers.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/fetch/headers.js b/test/fetch/headers.js
index d47d6412102..6b4b413c277 100644
--- a/test/fetch/headers.js
+++ b/test/fetch/headers.js
@@ -194,6 +194,7 @@ tap.test('Headers delete', t => {
     t.throws(() => headers.delete('invalid @ header ? name'), 'throws on invalid name')
   })
 
+  // https://github.com/nodejs/undici/issues/2429
   t.test('`Headers#delete` returns undefined', t => {
     t.plan(2)
     const headers = new Headers({ test: 'test' })

From f198341af4c209b4c5aab3ef55f491aeec2cfdad Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Tue, 14 Nov 2023 04:18:02 +0900
Subject: [PATCH 5/5] revert

---
 lib/fetch/headers.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/fetch/headers.js b/lib/fetch/headers.js
index 29587763bac..2971e63746d 100644
--- a/lib/fetch/headers.js
+++ b/lib/fetch/headers.js
@@ -301,6 +301,10 @@ class Headers {
 
     // 6. If this’s header list does not contain name, then
     //    return.
+    if (!this[kHeadersList].contains(name)) {
+      return
+    }
+
     // 7. Delete name from this’s header list.
     // 8. If this’s guard is "request-no-cors", then remove
     //    privileged no-CORS request headers from this.