encoding/csv: document ReadAll behavior at EOF
Fixes #2847.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5641050
diff --git a/src/pkg/encoding/csv/reader.go b/src/pkg/encoding/csv/reader.go
index ae0f567..9aa398e 100644
--- a/src/pkg/encoding/csv/reader.go
+++ b/src/pkg/encoding/csv/reader.go
@@ -156,6 +156,9 @@
// ReadAll reads all the remaining records from r.
// Each record is a slice of fields.
+// A successful call returns err == nil, not err == EOF. Because ReadAll is
+// defined to read until EOF, it does not treat end of file as an error to be
+// reported.
func (r *Reader) ReadAll() (records [][]string, err error) {
for {
record, err := r.Read()
