From beed0c0e5fbeec32047e2142aaf1380f82286df1 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Fri, 29 Jan 2016 16:23:43 -0600
Subject: [PATCH] Fix (r *msgReader) rxMsg() error guard clause

rxMsg() has a guard clause that checks if the msgReader has already
encountered an error. It should return that pre-existing error. It
was incorrectly returning a local `err` variable instead of `r.err`.
---
 CHANGELOG.md  | 1 +
 msg_reader.go | 6 +++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f946d67f..cef2eba0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # Tip
 
+* Fix msgReader.rxMsg bug when msgReader already has error
 * Add support for database/sql.Scanner and database/sql/driver.Valuer interfaces
 * Go float64 can no longer be encoded to a PostgreSQL float4
 * Add ConnPool.Reset method
diff --git a/msg_reader.go b/msg_reader.go
index 9098c20a..4c2d9805 100644
--- a/msg_reader.go
+++ b/msg_reader.go
@@ -32,9 +32,9 @@ func (r *msgReader) fatal(err error) {
 }
 
 // rxMsg reads the type and size of the next message.
-func (r *msgReader) rxMsg() (t byte, err error) {
+func (r *msgReader) rxMsg() (byte, error) {
 	if r.err != nil {
-		return 0, err
+		return 0, r.err
 	}
 
 	if r.msgBytesRemaining > 0 {
@@ -46,7 +46,7 @@ func (r *msgReader) rxMsg() (t byte, err error) {
 	}
 
 	b := r.buf[0:5]
-	_, err = io.ReadFull(r.reader, b)
+	_, err := io.ReadFull(r.reader, b)
 	r.msgBytesRemaining = int32(binary.BigEndian.Uint32(b[1:])) - 4
 	return b[0], err
 }