From 212c84564495fe99a337d0407cea91e8b71258be Mon Sep 17 00:00:00 2001
From: zhenweijin <zhenwei.jin@intel.com>
Date: Thu, 21 Mar 2024 23:25:01 +0800
Subject: [PATCH] fs: keep fs.promises.readFile read until EOF is reached

---
 lib/internal/fs/promises.js | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 676583ffea5d00..0a5725915261f6 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -535,6 +535,7 @@ async function readFileHandle(filehandle, options) {
     throw new ERR_FS_FILE_TOO_LARGE(size);
 
   let totalRead = 0;
+  const noSize = size === 0;
   let buffer = Buffer.allocUnsafeSlow(length);
   let result = '';
   let offset = 0;
@@ -557,7 +558,7 @@ async function readFileHandle(filehandle, options) {
 
     if (bytesRead === 0 ||
         totalRead === size ||
-        (bytesRead !== buffer.length && !chunkedRead)) {
+        (bytesRead !== buffer.length && !chunkedRead && !noSize)) {
       const singleRead = bytesRead === totalRead;
 
       const bytesToCheck = chunkedRead ? totalRead : bytesRead;
@@ -567,7 +568,7 @@ async function readFileHandle(filehandle, options) {
       }
 
       if (!encoding) {
-        if (size === 0 && !singleRead) {
+        if (noSize && !singleRead) {
           ArrayPrototypePush(buffers, buffer);
           return Buffer.concat(buffers, totalRead);
         }
@@ -582,7 +583,8 @@ async function readFileHandle(filehandle, options) {
     }
 
     if (encoding) {
-      result += decoder.write(buffer);
+      result += decoder.write(noSize && bytesRead !== kReadFileUnknownBufferLength ?
+        buffer.subarray(0, bytesRead) : buffer);
     } else if (size !== 0) {
       offset = totalRead;
     } else {