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/base/natural_sort.go

@@ -52,7 +52,7 @@ func naturalSortTrimZeros(num string) string {
 }
 
 // NaturalSortCompare compares two strings so that they could be sorted in natural order
-func NaturalSortCompare(s1, s2 string) int {
+func NaturalSortCompare(s1, s2 string) (ret int) {
 	// There is a bug in Golang's collate package: https://github.com/golang/go/issues/67997
 	// text/collate: CompareString(collate.Numeric) returns wrong result for "0.0" vs "1.0" #67997
 	// So we need to handle the number parts by ourselves
@@ -70,8 +70,7 @@ func NaturalSortCompare(s1, s2 string) int {
 				}
 				if cmp := strings.Compare(num1, num2); cmp != 0 {
 					return cmp // equal digit count, so byte order is numeric order
-				}
-				return len(part1) - len(part2) // equal value, fewer leading zeros sorts first
+				} // else: naturally equal value, leave it to the outer return
 			}
 		} else {
 			if cmp := c.CompareString(part1, part2); cmp != 0 {
@@ -80,5 +79,6 @@ func NaturalSortCompare(s1, s2 string) int {
 		}
 		pos1, pos2 = end1, end2
 	}
-	return len(s1) - len(s2)
+	// each field is naturally equal, just use string comparison: "v1.02.3" < "v1.2.03"
+	return strings.Compare(s1, s2)
 }

modules/base/natural_sort_test.go

@@ -21,6 +21,8 @@ func TestNaturalSortLess(t *testing.T) {
 	testLess("", "a")
 	testLess("", "1")
 
+	testLess("v1.02.3", "v1.2.03")
+	testLess("1.01.0", "1.1.1")
 	testLess("v1.2", "v1.2.0")
 	testLess("v1.2.0", "v1.10.0")
 	testLess("v1.20.0", "v1.29.0")
@@ -42,7 +44,7 @@ func TestNaturalSortLess(t *testing.T) {
 	testLess("0.txt", "1.txt")
 
 	testLess("file0001", "file2")
-	testLess("a8", "a08")
+	testLess("a08", "a8")
 	testLess("00", "1")
 	testLess("0", "00") // equal value, fewer leading zeros sorts first
 }

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)
+	}
+}