From c6cec81e2cf5966c1c6acdeba1d59acea9b71225 Mon Sep 17 00:00:00 2001
From: Fredrik Petrini <fredrik.petrini@gmail.com>
Date: Mon, 8 Oct 2018 11:39:18 +0200
Subject: [PATCH] Fix: Handle (n > 0 and err == io.EOF) in CopyFromReader as
 per io.Reader documentation

---
 copy_from.go      |  2 +-
 copy_from_test.go | 93 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 1 deletion(-)

diff --git a/copy_from.go b/copy_from.go
index 314d441f..27e2fc9a 100644
--- a/copy_from.go
+++ b/copy_from.go
@@ -298,7 +298,7 @@ func (c *Conn) CopyFromReader(r io.Reader, sql string) error {
 	sp := len(buf)
 	for {
 		n, err := r.Read(buf[5:cap(buf)])
-		if err == io.EOF {
+		if err == io.EOF && n == 0 {
 			break
 		}
 		buf = buf[0 : n+5]
diff --git a/copy_from_test.go b/copy_from_test.go
index 0ed88b72..4c239b05 100644
--- a/copy_from_test.go
+++ b/copy_from_test.go
@@ -1,7 +1,12 @@
 package pgx_test
 
 import (
+	"compress/gzip"
+	"fmt"
+	"io/ioutil"
+	"os"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -639,3 +644,91 @@ func TestConnCopyFromReaderNoTableError(t *testing.T) {
 
 	ensureConnValid(t, conn)
 }
+
+func TestConnCopyFromGzipReader(t *testing.T) {
+	t.Parallel()
+
+	conn := mustConnect(t, *defaultConnConfig)
+	defer closeConn(t, conn)
+
+	mustExec(t, conn, `create temporary table foo(
+		a int4,
+		b varchar
+	)`)
+
+	f, err := ioutil.TempFile("", "*")
+	if err != nil {
+		t.Fatalf("Unexpected error for ioutil.TempFile: %v", err)
+	}
+
+	gw := gzip.NewWriter(f)
+
+	inputRows := [][]interface{}{}
+	for i := 0; i < 1000; i++ {
+		val := strconv.Itoa(i * i)
+		inputRows = append(inputRows, []interface{}{int32(i), val})
+		_, err = gw.Write([]byte(fmt.Sprintf("%d,\"%s\"\n", i, val)))
+		if err != nil {
+			t.Errorf("Unexpected error for gw.Write: %v", err)
+		}
+	}
+
+	err = gw.Close()
+	if err != nil {
+		t.Fatalf("Unexpected error for gw.Close: %v", err)
+	}
+
+	_, err = f.Seek(0, 0)
+	if err != nil {
+		t.Fatalf("Unexpected error for f.Seek: %v", err)
+	}
+
+	gr, err := gzip.NewReader(f)
+	if err != nil {
+		t.Fatalf("Unexpected error for gzip.NewReader: %v", err)
+	}
+
+	err = conn.CopyFromReader(gr, "COPY foo FROM STDIN WITH (FORMAT csv)")
+	if err != nil {
+		t.Errorf("Unexpected error for CopyFromReader: %v", err)
+	}
+
+	err = gr.Close()
+	if err != nil {
+		t.Errorf("Unexpected error for gr.Close: %v", err)
+	}
+
+	err = f.Close()
+	if err != nil {
+		t.Errorf("Unexpected error for f.Close: %v", err)
+	}
+
+	err = os.Remove(f.Name())
+	if err != nil {
+		t.Errorf("Unexpected error for os.Remove: %v", err)
+	}
+
+	rows, err := conn.Query("select * from foo")
+	if err != nil {
+		t.Errorf("Unexpected error for Query: %v", err)
+	}
+
+	var outputRows [][]interface{}
+	for rows.Next() {
+		row, err := rows.Values()
+		if err != nil {
+			t.Errorf("Unexpected error for rows.Values(): %v", err)
+		}
+		outputRows = append(outputRows, row)
+	}
+
+	if rows.Err() != nil {
+		t.Errorf("Unexpected error for rows.Err(): %v", rows.Err())
+	}
+
+	if !reflect.DeepEqual(inputRows, outputRows) {
+		t.Errorf("Input rows and output rows do not equal")
+	}
+
+	ensureConnValid(t, conn)
+}