better error message when Restore failed

Signed-off-by: ekexium <[email protected]>

session/nontransactional.go

@@ -197,7 +197,7 @@ func splitDeleteWorker(ctx context.Context, jobs []job, stmt *ast.NonTransaction
 
 		// if the first job failed, there is a large chance that all jobs will fail. So return early.
 		if i == 0 && jobs[i].err != nil {
-			return nil, errors.Wrap(jobs[i].err, "Early return: error occurred in the first job. All jobs are canceled")
+			return nil, errors.Annotate(jobs[i].err, "Early return: error occurred in the first job. All jobs are canceled")
 		}
 	}
 	return splitStmts, nil
@@ -271,7 +271,7 @@ func doOneJob(ctx context.Context, job *job, totalJobCount int, options statemen
 		format.RestoreBracketAroundBinaryOperation|
 		format.RestoreStringWithoutCharset, &sb))
 	if err != nil {
-		job.err = err
+		job.err = errors.Annotate(err, "Failed to restore delete statement")
 		return ""
 	}
 	deleteSQL := sb.String()
@@ -436,7 +436,7 @@ func buildSelectSQL(stmt *ast.NonTransactionalDeleteStmt, se Session) (*ast.Tabl
 			format.RestoreBracketAroundBinaryOperation|
 			format.RestoreStringWithoutCharset, &sb))
 		if err != nil {
-			return nil, "", nil, errors.Trace(err)
+			return nil, "", nil, errors.Annotate(err, "Failed to restore where clause in non-transactional delete")
 		}
 	} else {
 		sb.WriteString("TRUE")

session/nontransactional_test.go

@@ -401,3 +401,22 @@ func TestNonTransactionalDeleteAlias(t *testing.T) {
 		tk.MustQuery("select count(*) from test.t").Check(testkit.Rows("5"))
 	}
 }
+
+func TestNonTransactionalDeleteShardOnUnsupportedTypes(t *testing.T) {
+	// When some day the test fail because such types are supported, we can update related docs and consider remove the test.
+	store, clean := createStorage(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a set('e0', 'e1', 'e2'), b int, key(a))")
+	tk.MustExec("insert into t values ('e2,e0', 3)")
+	err := tk.ExecToErr("split on a limit 1 delete from t")
+	require.Error(t, err)
+	tk.MustQuery("select count(*) from t").Check(testkit.Rows("1"))
+
+	tk.MustExec("create table t2(a enum('e0', 'e1', 'e2'), b int, key(a))")
+	tk.MustExec("insert into t2 values ('e0', 1)")
+	err = tk.ExecToErr("split on a limit 1 delete from t2")
+	require.Error(t, err)
+	tk.MustQuery("select count(*) from t2").Check(testkit.Rows("1"))
+}