fix(packages): list highest CRAN version in PACKAGES index (#39793)

Fixes https://github.com/go-gitea/gitea/issues/35728

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/packages/cran/metadata.go

@@ -7,12 +7,14 @@ import (
 	"archive/tar"
 	"archive/zip"
 	"bufio"
+	"cmp"
 	"compress/gzip"
 	"io"
 	"path"
 	"regexp"
 	"strings"
 
+	"gitea.dev/modules/base"
 	"gitea.dev/modules/packages"
 	"gitea.dev/modules/util"
 )
@@ -234,6 +236,11 @@ func setField(p *Package, data string) error {
 	return nil
 }
 
+// CompareVersions returns -1, 0 or 1, R treats "." and "-" as equivalent separators
+func CompareVersions(a, b string) int {
+	return cmp.Compare(base.NaturalSortCompare(strings.ReplaceAll(a, "-", "."), strings.ReplaceAll(b, "-", ".")), 0)
+}
+
 func splitAndTrim(s string) []string {
 	items := strings.Split(s, ", ")
 	for i := range items {

modules/packages/cran/metadata_test.go

@@ -159,3 +159,20 @@ func TestParseDescription(t *testing.T) {
 		assert.True(t, p.Metadata.NeedsCompilation)
 	})
 }
+
+func TestCompareVersions(t *testing.T) {
+	cases := []struct {
+		a, b     string
+		expected int
+	}{
+		{"1.0.3", "1.0.2", 1},
+		{"0.9.10", "0.9.9", 1},
+		{"2.5.2", "3.0.2", -1},
+		{"1.0-1", "1.0.0", 1},
+		{"1.0-2", "1.0.2", 0},
+		{"1.0", "1.0.0", -1},
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.expected, CompareVersions(c.a, c.b), "%s vs %s", c.a, c.b)
+	}
+}