Merge 'Fix type checking in index paging' from Piotr Sarna

When recreating the paging state from an indexed query,
a bunch of panic checks were introduced to make sure that
the code is correct. However, one of the checks is too eager -
namely, it throws an error if the base column type is not equal
to the view column type. It usually works correctly, unless the
base column type is a clustering key with DESC clustering order,
in which case the type is actually "reversed". From the point of view
of the paging state generation it's not important, because both
types deserialize in the same way, so the check should be less
strict and allow the base type to be reversed.

Tests: unit(release), along with the additional test case
       introduced in this series; the test also passes
       on Cassandra

Fixes #8666

Closes #8667

* github.com:scylladb/scylla:
  test: add a test case for paging with desc clustering order
  cql3: relax a type check for index paging

(cherry picked from commit 593ad4de1e)

cql3/statements/select_statement.cc

@@ -461,7 +461,7 @@ generate_base_key_from_index_pk(const partition_key& index_pk, const std::option
         if (!view_col) {
             throw std::runtime_error(format("Base key column not found in the view: {}", base_col.name_as_text()));
         }
-        if (base_col.type != view_col->type) {
+        if (base_col.type->without_reversed() != *view_col->type) {
             throw std::runtime_error(format("Mismatched types for base and view columns {}: {} and {}",
                     base_col.name_as_text(), base_col.type->cql3_type_name(), view_col->type->cql3_type_name()));
         }

test/cql-pytest/test_secondary_index.py

@@ -20,6 +20,7 @@
 import time
 import pytest
 from cassandra.protocol import SyntaxException, AlreadyExists, InvalidRequest, ConfigurationException, ReadFailure
+from cassandra.query import SimpleStatement
 
 from util import new_test_table
 
@@ -64,3 +65,19 @@ def test_partition_order_with_si(cql, test_keyspace):
                 pass
             time.sleep(0.1)
         assert tokens2 == tokens
+
+# Test that the paging state works properly for indexes on tables
+# with descending clustering order. There was a problem with indexes
+# created on clustering keys with DESC clustering order - they are represented
+# as "reverse" types internally and Scylla assertions failed that the base type
+# is different from the underlying view type, even though, from the perspective
+# of deserialization, they're equal. Issue #8666
+def test_paging_with_desc_clustering_order(cql, test_keyspace):
+    schema = 'p int, c int, primary key (p,c)'
+    extra = 'with clustering order by (c desc)'
+    with new_test_table(cql, test_keyspace, schema, extra) as table:
+        cql.execute(f"CREATE INDEX ON {table}(c)")
+        for i in range(3):
+            cql.execute(f"INSERT INTO {table}(p,c) VALUES ({i}, 42)")
+        stmt = SimpleStatement(f"SELECT * FROM {table} WHERE c = 42", fetch_size=1)
+        assert len([row for row in cql.execute(stmt)]) == 3