Propagate errors encountered when reading file

godotenv.go

@@ -143,6 +143,10 @@ func readFile(filename string) (envMap map[string]string, err error) {
 		lines = append(lines, scanner.Text())
 	}
 
+	if err = scanner.Err(); err != nil {
+		return
+	}
+
 	for _, fullLine := range lines {
 		if !isIgnoredLine(fullLine) {
 			key, value, err := parseLine(fullLine)