Ar.Next() error: strconv.Atoi: parsing \"\": invalid syntax

[rgmz]

When attempting to read *.a files, an error is occasionally encountered:

strconv.Atoi: parsing \"\": invalid syntax

The source of this is Ar.Read > parseArEntry > toDecimal. It seems that one of the values is empty, resulting in an error.

1. go-debian/deb/ar.go

   Line 89 in 246d63d

   entry, err := parseArEntry(line)

2. go-debian/deb/ar.go

   Line 153 in 246d63d

   intValue, err := toDecimal(value)

3. go-debian/deb/ar.go

   Line 107 in 246d63d

   out, err := strconv.Atoi(stream)

This can be reproduced with the following file: https://github.com/openshift/ci-operator-prowgen/blob/ee31ec067b4670222de32ceecd01184b4eb52db3/vendor/golang.org/x/tools/go/gccgoexportdata/testdata/long.a

[rgmz]

Based on my own debugging, the failing line is:

47 47 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 51 50 32 32 32 32 32 32 32 32 96 10

For that line, the OwnerID, GroupID , and Timestamp are all empty space.

Full output:

Reading line: [47 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 49 52 55 56 55 49 51 54 52 50 32 32 48 32 32 32 32 32 48 32 32 32 32 32 48 32 32 32 32 32 32 32 52 32 32 32 32 32 32 32 32 32 96 10]
Reading target: Timestamp, value is: '[49 52 55 56 55 49 51 54 52 50 32 32]', int value: 1478713642
Reading target: OwnerID, value is: '[48 32 32 32 32 32]', int value: 0
Reading target: GroupID, value is: '[48 32 32 32 32 32]', int value: 0
Reading target: Size, value is: '[52 32 32 32 32 32 32 32 32 32]', int value: 4

Reading line: [47 47 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 51 50 32 32 32 32 32 32 32 32 96 10]
Reading target: Size, value is: '[51 50 32 32 32 32 32 32 32 32]', int value: 32
error reading entry: strconv.Atoi: parsing "": invalid syntax