Improve natural sort (#29611)

Hugely simplify the code, and add more tests (only new approach could
pass)

diff --git a/modules/base/natural_sort.go b/modules/base/natural_sort.go
index e920177f8944c6c929c447af593a26d11171667c..0f90ec70cef44f3ea248c9b9c8a9cb259a90d598 100644 (file)
--- a/modules/base/natural_sort.go
+++ b/modules/base/natural_sort.go
@@ -4,85 +4,12 @@
 package base
 
 import (
-       "math/big"
-       "unicode/utf8"
+       "golang.org/x/text/collate"
+       "golang.org/x/text/language"
 )
 
 // NaturalSortLess compares two strings so that they could be sorted in natural order
 func NaturalSortLess(s1, s2 string) bool {
-       var i1, i2 int
-       for {
-               rune1, j1, end1 := getNextRune(s1, i1)
-               rune2, j2, end2 := getNextRune(s2, i2)
-               if end1 || end2 {
-                       return end1 != end2 && end1
-               }
-               dec1 := isDecimal(rune1)
-               dec2 := isDecimal(rune2)
-               var less, equal bool
-               if dec1 && dec2 {
-                       i1, i2, less, equal = compareByNumbers(s1, i1, s2, i2)
-               } else if !dec1 && !dec2 {
-                       equal = rune1 == rune2
-                       less = rune1 < rune2
-                       i1 = j1
-                       i2 = j2
-               } else {
-                       return rune1 < rune2
-               }
-               if !equal {
-                       return less
-               }
-       }
-}
-
-func getNextRune(str string, pos int) (rune, int, bool) {
-       if pos < len(str) {
-               r, w := utf8.DecodeRuneInString(str[pos:])
-               // Fallback to ascii
-               if r == utf8.RuneError {
-                       r = rune(str[pos])
-                       w = 1
-               }
-               return r, pos + w, false
-       }
-       return 0, pos, true
-}
-
-func isDecimal(r rune) bool {
-       return '0' <= r && r <= '9'
-}
-
-func compareByNumbers(str1 string, pos1 int, str2 string, pos2 int) (i1, i2 int, less, equal bool) {
-       d1, d2 := true, true
-       var dec1, dec2 string
-       for d1 || d2 {
-               if d1 {
-                       r, j, end := getNextRune(str1, pos1)
-                       if !end && isDecimal(r) {
-                               dec1 += string(r)
-                               pos1 = j
-                       } else {
-                               d1 = false
-                       }
-               }
-               if d2 {
-                       r, j, end := getNextRune(str2, pos2)
-                       if !end && isDecimal(r) {
-                               dec2 += string(r)
-                               pos2 = j
-                       } else {
-                               d2 = false
-                       }
-               }
-       }
-       less, equal = compareBigNumbers(dec1, dec2)
-       return pos1, pos2, less, equal
-}
-
-func compareBigNumbers(dec1, dec2 string) (less, equal bool) {
-       d1, _ := big.NewInt(0).SetString(dec1, 10)
-       d2, _ := big.NewInt(0).SetString(dec2, 10)
-       cmp := d1.Cmp(d2)
-       return cmp < 0, cmp == 0
+       c := collate.New(language.English, collate.Numeric)
+       return c.CompareString(s1, s2) < 0
 }

diff --git a/modules/base/natural_sort_test.go b/modules/base/natural_sort_test.go
index 91e864ad2af7e4a655c62a1fad09c25797aaee82..f27a4eb53a249da8754f4a519cb36d1d432c08a9 100644 (file)
--- a/modules/base/natural_sort_test.go
+++ b/modules/base/natural_sort_test.go
@@ -11,7 +11,7 @@ import (
 
 func TestNaturalSortLess(t *testing.T) {
        test := func(s1, s2 string, less bool) {
-               assert.Equal(t, less, NaturalSortLess(s1, s2))
+               assert.Equal(t, less, NaturalSortLess(s1, s2), "s1=%q, s2=%q", s1, s2)
        }
        test("v1.20.0", "v1.2.0", false)
        test("v1.20.0", "v1.29.0", true)
@@ -20,4 +20,11 @@ func TestNaturalSortLess(t *testing.T) {
        test("a-1-a", "a-1-b", true)
        test("2", "12", true)
        test("a", "ab", true)
+
+       test("A", "b", true)
+       test("a", "B", true)
+
+       test("cafe", "café", true)
+       test("café", "cafe", false)
+       test("caff", "café", false)
 }