[CASSANDRA-17913] Nested selection of reversed collections fails

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0.10, 4.1.2, 5.0-alpha1, 5.0
• Component/s: Consistency/Coordination, CQL/Semantics, Legacy/Local Write-Read Paths
• Bug Category: Correctness - Unrecoverable Corruption / Loss
• Severity: Normal
• Complexity: Normal
• Discovered By: Fuzz Test
• Platform: All
• Since Version: 4.0.0

Source Control Link

https://github.com/apache/cassandra/commit/2fce3025c448316720d9cf7447fe7d1d34e17625

Test and Documentation Plan

unittests

• Assignee: Maciej Sokol
• Reporter: David Capwell

Authors

Maciej Sokol

• Created: 21/Sep/22 16:31
• Updated: 12/Sep/23 13:03
• Resolved: 14/Apr/23 10:16

Description

The following test fails caused by the fact we make reversed a type that wraps the underline type

@Test
    public void testMapsReversed() throws Throwable
    {
        createTable("CREATE TABLE %s (" +
                    "   k int, " +
                    "   c frozen<map<text, int>>, " +
                    "   v int, " +
                    "   PRIMARY KEY(k, c)" +
                    ") WITH CLUSTERING ORDER BY (c DESC)");

        execute("SELECT c['testing'] FROM %s");
    }

With the error

org.apache.cassandra.exceptions.InvalidRequestException: Invalid element selection: c is of type frozen<map<text, int>> is not a collection

When you look in a debugger you see that the real type is ReversedType(MapType(…)), so the current checks fail.

Additional information for newcomers:

• The problem impact element selection as well as range selection that where introduced in CASSANDRA-7396 as part of 4.0. So the patch will need to be done for 4.0.
• The checks that needs to be modified is in Selectable.WithElementSelection and Selectable.WithSliceSelection
• The unit tests should be added to CollectionsTest

Issue Links

• links to: GitHub Pull Request #1978
• links to: GitHub Pull Request #2270
• links to: GitHub Pull Request #2271
• links to: GitHub Pull Request #2272