From 95e378a28b0e0ba1d05f2a41bc27a7368aac66f4 Mon Sep 17 00:00:00 2001
From: "Kevin (Kun) \"Kassimo\" Qian" <kevinkassimo@gmail.com>
Date: Mon, 31 Dec 2018 04:00:28 -0500
Subject: [PATCH] Avoid textproto crashing on empty reader
 (denoland/deno_std#50)

Original: https://github.com/denoland/deno_std/commit/9eb6aa5fd9da9da9cd2b96a5199cf9b9128fd456
---
 net/textproto.ts      | 5 +++--
 net/textproto_test.ts | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/textproto.ts b/net/textproto.ts
index 342d74b33e..832299e1c2 100644
--- a/net/textproto.ts
+++ b/net/textproto.ts
@@ -118,11 +118,12 @@ export class TextProtoReader {
 
   async readLineSlice(): Promise<[Uint8Array, BufState]> {
     // this.closeDot();
-    let line: null | Uint8Array;
+    let line: Uint8Array;
     while (true) {
       let [l, more, err] = await this.r.readLine();
       if (err != null) {
-        return [null, err];
+        // Go's len(typed nil) works fine, but not in JS
+        return [new Uint8Array(0), err];
       }
       // Avoid the copy if the first call produced a full line.
       if (line == null && !more) {
diff --git a/net/textproto_test.ts b/net/textproto_test.ts
index ad7e6a2c41..3af21247a6 100644
--- a/net/textproto_test.ts
+++ b/net/textproto_test.ts
@@ -93,3 +93,10 @@ test(async function textprotoAppend() {
   const joined = append(u1, u2);
   assertEqual(dec.decode(joined), "Hello World");
 });
+
+test(async function textprotoReadEmpty() {
+  let r = reader("");
+  let [m, err] = await r.readMIMEHeader();
+  // Should not crash!
+  assertEqual(err, "EOF");
+});