*: replace compareDatum by compare and fix wrong optimize order by

planner/core/integration_test.go

@@ -4897,3 +4897,16 @@ func (s *testIntegrationSuite) TestIssue30094(c *C) {
 		"  └─TableFullScan 10000.00 cop[tikv] table:t30094 keep order:false, stats:pseudo",
 	))
 }
+
+func (s *testIntegrationSerialSuite) TestIssue30271(c *C) {
+	defer collate.SetNewCollationEnabledForTest(false)
+	collate.SetNewCollationEnabledForTest(true)
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a char(10), b char(10), c char(10), index (a, b, c)) collate utf8mb4_bin;")
+	tk.MustExec("insert into t values ('b', 'a', '1'), ('b', 'A', '2'), ('c', 'a', '3');")
+	tk.MustExec("set names utf8mb4 collate utf8mb4_general_ci;")
+	tk.MustQuery("select * from t where (a>'a' and b='a') or (b = 'A' and a < 'd') order by a,c;").Check(testkit.Rows("b a 1", "b A 2", "c a 3"))
+
+}

types/datum.go

@@ -2175,7 +2175,8 @@ func (ds *datumsSorter) Len() int {
 }
 
 func (ds *datumsSorter) Less(i, j int) bool {
-	cmp, err := ds.datums[i].CompareDatum(ds.sc, &ds.datums[j])
+	// TODO: set collation explicitly when rewrites feedback.
+	cmp, err := ds.datums[i].Compare(ds.sc, &ds.datums[j], collate.GetCollator(ds.datums[i].Collation()))
 	if err != nil {
 		ds.err = errors.Trace(err)
 		return true
@@ -2357,7 +2358,7 @@ func ChangeReverseResultByUpperLowerBound(
 		resRetType.Decimal = int(res.GetMysqlDecimal().GetDigitsInt())
 	}
 	bound := getDatumBound(&resRetType, rType)
-	cmp, err := d.CompareDatum(sc, &bound)
+	cmp, err := d.Compare(sc, &bound, collate.GetCollator(resRetType.Collate))
 	if err != nil {
 		return d, err
 	}

types/datum_test.go

@@ -490,7 +490,7 @@ func TestChangeReverseResultByUpperLowerBound(t *testing.T) {
 		reverseRes, err := ChangeReverseResultByUpperLowerBound(sc, test.retType, test.a, test.roundType)
 		require.NoError(t, err)
 		var cmp int
-		cmp, err = reverseRes.CompareDatum(sc, &test.res)
+		cmp, err = reverseRes.Compare(sc, &test.res, collate.GetBinaryCollator())
 		require.NoError(t, err)
 		require.Equalf(t, 0, cmp, "%dth got:%#v, expect:%#v", ith, reverseRes, test.res)
 	}

util/ranger/detacher.go

@@ -715,7 +715,8 @@ func isSameValue(sc *stmtctx.StatementContext, lhs, rhs *valueInfo) (bool, error
 	if lhs == nil || rhs == nil || lhs.mutable || rhs.mutable || lhs.value.Kind() != rhs.value.Kind() {
 		return false, nil
 	}
-	cmp, err := lhs.value.CompareDatum(sc, rhs.value)
+	// binary collator may not the best choice, but it can make sure the result is correct.
+	cmp, err := lhs.value.Compare(sc, rhs.value, collate.GetBinaryCollator())
 	if err != nil {
 		return false, err
 	}

util/rowDecoder/decoder_test.go

@@ -130,7 +130,7 @@ func TestRowDecoder(t *testing.T) {
 		for i, col := range cols[:len(cols)-1] {
 			v, ok := r[col.ID]
 			if ok {
-				equal, err1 := v.CompareDatum(sc, &row.output[i])
+				equal, err1 := v.Compare(sc, &row.output[i], collate.GetBinaryCollator())
 				require.Nil(t, err1)
 				require.Equal(t, 0, equal)
 			} else {
@@ -144,7 +144,7 @@ func TestRowDecoder(t *testing.T) {
 		for k, v := range r2 {
 			v1, ok := r[k]
 			require.True(t, ok)
-			equal, err1 := v.CompareDatum(sc, &v1)
+			equal, err1 := v.Compare(sc, &v1, collate.GetBinaryCollator())
 			require.Nil(t, err1)
 			require.Equal(t, 0, equal)
 		}