packets: do not call function on nulled value (go-sql-driver#678)

julienschmidt · Brigitte Lamarche · commit b3a093e1ccb6 · 2018-03-23T11:29:56.000-04:00
diff --git a/packets.go b/packets.go
@@ -1155,10 +1155,11 @@ func (rows *binaryRows) readRow(dest []driver.Value) error {
 			}
 			return io.EOF
 		}
+		mc := rows.mc
 		rows.mc = nil
 
 		// Error otherwise
-		return rows.mc.handleErrorPacket(data)
+		return mc.handleErrorPacket(data)
 	}
 
 	// NULL-bitmap,  [(column-count + 7 + 2) / 8 bytes]

Original file line number	Diff line number	Diff line change
`@@ -1155,10 +1155,11 @@ func (rows *binaryRows) readRow(dest []driver.Value) error {`
`1155`	`1155`	`}`
`1156`	`1156`	`return io.EOF`
`1157`	`1157`	`}`
	`1158`	`+ mc := rows.mc`
`1158`	`1159`	`rows.mc = nil`
`1159`	`1160`
`1160`	`1161`	`// Error otherwise`
`1161`		`- return rows.mc.handleErrorPacket(data)`
	`1162`	`+ return mc.handleErrorPacket(data)`
`1162`	`1163`	`}`
`1163`	`1164`
`1164`	`1165`	`// NULL-bitmap, [(column-count + 7 + 2) / 8 bytes]`