From 1926476780685fefbf60893c5bf0b527a9e22d5e Mon Sep 17 00:00:00 2001
From: Viacheslav Poturaev <vearutop@gmail.com>
Date: Tue, 9 Feb 2021 17:56:27 +0100
Subject: [PATCH] Wait for io.EOF when decoding a stream, fixes #123

---
 decode_stream.go |  2 +-
 stream_test.go   | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/decode_stream.go b/decode_stream.go
index 561de91..f54400d 100644
--- a/decode_stream.go
+++ b/decode_stream.go
@@ -75,7 +75,7 @@ func (s *stream) read() bool {
 	buf[last] = nul
 	n, err := s.r.Read(buf[:last])
 	s.length = s.cursor + int64(n)
-	if n < last || err == io.EOF {
+	if err == io.EOF {
 		s.allRead = true
 	} else if err != nil {
 		return false
diff --git a/stream_test.go b/stream_test.go
index 8fee6cd..43588e4 100644
--- a/stream_test.go
+++ b/stream_test.go
@@ -6,6 +6,7 @@ package json_test
 
 import (
 	"bytes"
+	"compress/gzip"
 	"io"
 	"io/ioutil"
 	"log"
@@ -463,3 +464,41 @@ func TestHTTPDecoding(t *testing.T) {
 		t.Errorf("err = %v; want io.EOF", err)
 	}
 }
+
+func TestGzipStreaming(t *testing.T) {
+	type someStruct struct {
+		ID   int      `json:"id"`
+		Text []string `json:"text"`
+	}
+
+	manyItems := strings.Repeat(`"Quis autem vel eum iure reprehenderit, qui in ea voluptate velit esse, quam`+
+		` nihil molestiae consequatur, vel illum, qui dolorem eum fugiat, quo voluptas nulla pariatur?",`, 400)
+
+	longJSON := `{"id":123,"text":[` + manyItems[0:len(manyItems)-1] + `]}`
+
+	compressed := bytes.NewBuffer(nil)
+	gw := gzip.NewWriter(compressed)
+
+	_, err := io.Copy(gw, bytes.NewReader([]byte(longJSON)))
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	err = gw.Close()
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	gr, err := gzip.NewReader(bytes.NewReader(compressed.Bytes()))
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	var v someStruct
+	dec := json.NewDecoder(gr)
+
+	err = dec.Decode(&v)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+}