fix(rpm): keep the epoch when parsing RPM manifest packages (#5201)

---------

Signed-off-by: Sueun Cho <sueun.dev@gmail.com>
Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>
Co-authored-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>

syft/pkg/cataloger/redhat/package.go

@@ -59,17 +59,14 @@ func newMetadataFromManifestLine(entry string) (*pkg.RpmDBEntry, error) {
 	version := versionParts[0]
 	release := versionParts[1]
 
-	converted, err := strconv.Atoi(parts[8])
+	// EPOCH is "(none)" when the package has no epoch; EPOCHNUM is the numeric form ("0" in that case)
 	var epoch *int
-	if err != nil || parts[5] == "(none)" {
+	if parts[5] != "(none)" {
-		epoch = nil
+		epoch = parseEpoch(parts[8])
-	} else {
-		epoch = &converted
 	}
 
-	converted, err = strconv.Atoi(parts[6])
 	var size int
-	if err == nil {
+	if converted, err := strconv.Atoi(parts[6]); err == nil {
 		size = converted
 	}
 	return &pkg.RpmDBEntry{

syft/pkg/cataloger/redhat/parse_rpm_manifest_test.go

@@ -1,8 +1,12 @@
 package redhat
 
 import (
+	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/pkg/cataloger/internal/pkgtest"
@@ -80,6 +84,23 @@ func TestParseRpmManifest(t *testing.T) {
 				Vendor:    "Microsoft Corporation",
 			},
 		},
+		{
+			Name:      "vim",
+			Version:   "2:9.0-1.cm2",
+			PURL:      "pkg:rpm/vim@9.0-1.cm2?arch=x86_64&epoch=2&upstream=vim-9.0-1.cm2.src.rpm",
+			Locations: file.NewLocationSet(location),
+			Type:      pkg.RpmPkg,
+			Metadata: pkg.RpmDBEntry{
+				Name:      "vim",
+				Epoch:     intRef(2),
+				Arch:      "x86_64",
+				Release:   "1.cm2",
+				Version:   "9.0",
+				SourceRpm: "vim-9.0-1.cm2.src.rpm",
+				Size:      45000,
+				Vendor:    "Microsoft Corporation",
+			},
+		},
 	}
 
 	pkgtest.NewCatalogTester().
@@ -88,3 +109,74 @@ func TestParseRpmManifest(t *testing.T) {
 		TestParser(t, parseRpmManifest)
 
 }
+
+func TestNewMetadataFromManifestLine(t *testing.T) {
+	// fields are: NAME, VERSION-RELEASE, INSTALLTIME, BUILDTIME, VENDOR, EPOCH, SIZE, ARCH, EPOCHNUM, SOURCERPM
+	line := func(epoch, size, epochNum string) string {
+		return strings.Join([]string{
+			"vim", "9.0-1.cm2", "1653816591", "1653753130", "Microsoft Corporation",
+			epoch, size, "x86_64", epochNum, "vim-9.0-1.cm2.src.rpm",
+		}, "\t")
+	}
+
+	tests := []struct {
+		name      string
+		entry     string
+		wantEpoch *int
+		wantSize  int
+		wantErr   require.ErrorAssertionFunc
+	}{
+		{
+			name:      "no epoch",
+			entry:     line("(none)", "45000", "0"),
+			wantEpoch: nil,
+			wantSize:  45000,
+		},
+		{
+			name:      "explicit zero epoch is distinct from no epoch",
+			entry:     line("0", "45000", "0"),
+			wantEpoch: intRef(0),
+			wantSize:  45000,
+		},
+		{
+			name:      "unparsable epochnum yields no epoch",
+			entry:     line("2", "45000", ""),
+			wantEpoch: nil,
+			wantSize:  45000,
+		},
+		{
+			name:      "unparsable size yields zero size",
+			entry:     line("2", "bogus", "2"),
+			wantEpoch: intRef(2),
+			wantSize:  0,
+		},
+		{
+			name:    "too few fields",
+			entry:   "vim\t9.0-1.cm2",
+			wantErr: require.Error,
+		},
+		{
+			name:    "version field missing the release",
+			entry:   strings.Replace(line("(none)", "45000", "0"), "9.0-1.cm2", "9.0", 1),
+			wantErr: require.Error,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.wantErr == nil {
+				tt.wantErr = require.NoError
+			}
+
+			metadata, err := newMetadataFromManifestLine(tt.entry)
+			tt.wantErr(t, err)
+			if err != nil {
+				return
+			}
+
+			require.NotNil(t, metadata)
+			assert.Equal(t, tt.wantEpoch, metadata.Epoch)
+			assert.Equal(t, tt.wantSize, metadata.Size)
+		})
+	}
+}

syft/pkg/cataloger/redhat/testdata/container-manifest-2

@@ -2,4 +2,5 @@ mariner-release	2.0-12.cm2	1653816591	1653753130	Microsoft Corporation	(none)	58
 filesystem	1.1-9.cm2	1653816591	1653628924	Microsoft Corporation	(none)	7596	x86_64	0	filesystem-1.1-9.cm2.src.rpm
 glibc	2.35-2.cm2	1653816591	1653628955	Microsoft Corporation	(none)	10855265	x86_64	0	glibc-2.35-2.cm2.src.rpm
 openssl-libs	1.1.1k-15.cm2	1653816591	1653631609	Microsoft Corporation	(none)	4365048	x86_64	0	openssl-1.1.1k-15.cm2.src.rpm
+vim	9.0-1.cm2	1653816591	1653753130	Microsoft Corporation	2	45000	x86_64	2	vim-9.0-1.cm2.src.rpm