From d498451cdf2d4181d0399ea1c86bd50fcacff311 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Jadwiszczak?=
 <michal.jadwiszczak@scylladb.com>
Date: Wed, 21 Jun 2023 10:55:08 +0200
Subject: [PATCH 1/2] cql3:statements:describe_statement: check pointer to
 UDF/UDA

While looking for specific UDF/UDA, result of
`functions::functions::find()` needs to be filtered out based on
function's type.

Fixes: #14360
---
 cql3/statements/describe_statement.cc | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/cql3/statements/describe_statement.cc b/cql3/statements/describe_statement.cc
index 57bfb5cff0a2..184218e4e1d8 100644
--- a/cql3/statements/describe_statement.cc
+++ b/cql3/statements/describe_statement.cc
@@ -179,7 +179,13 @@ future<std::vector<description>> function(replica::database& db, const sstring&
 
     auto udfs = boost::copy_range<std::vector<shared_ptr<const keyspace_element>>>(fs | boost::adaptors::transformed([] (const auto& f) {
         return dynamic_pointer_cast<const functions::user_function>(f.second);
+    }) | boost::adaptors::filtered([] (const auto& f) {
+        return f != nullptr;
     }));
+    if (udfs.empty()) {
+        throw exceptions::invalid_request_exception(format("Function '{}' not found in keyspace '{}'", name, ks));
+    }
+
     co_return co_await generate_descriptions(db, udfs, true);
 }
 
@@ -192,13 +198,19 @@ future<std::vector<description>> functions(replica::database& db,const sstring&
 
 future<std::vector<description>> aggregate(replica::database& db, const sstring& ks, const sstring& name) {
     auto fs = functions::functions::find(functions::function_name(ks, name));
-    if(fs.empty()) {
+    if (fs.empty()) {
         throw exceptions::invalid_request_exception(format("Aggregate '{}' not found in keyspace '{}'", name, ks));
     }
 
     auto udas = boost::copy_range<std::vector<shared_ptr<const keyspace_element>>>(fs | boost::adaptors::transformed([] (const auto& f) {
         return dynamic_pointer_cast<const functions::user_aggregate>(f.second);
+    }) | boost::adaptors::filtered([] (const auto& f) {
+        return f != nullptr;
     }));
+    if (udas.empty()) {
+        throw exceptions::invalid_request_exception(format("Aggregate '{}' not found in keyspace '{}'", name, ks));
+    }
+
     co_return co_await generate_descriptions(db, udas, true);
 }
 

From d3d9a15505a589e09722e92ac283453c611b3032 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Jadwiszczak?=
 <michal.jadwiszczak@scylladb.com>
Date: Wed, 21 Jun 2023 12:00:37 +0200
Subject: [PATCH 2/2] cql-pytest:test_describe: add test for filtering UDF and
 UDA

---
 test/cql-pytest/test_describe.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/test/cql-pytest/test_describe.py b/test/cql-pytest/test_describe.py
index f95e873c13a5..f1c9894d293b 100644
--- a/test/cql-pytest/test_describe.py
+++ b/test/cql-pytest/test_describe.py
@@ -12,6 +12,7 @@
 from pytest import fixture
 from contextlib import contextmanager
 from util import new_type, unique_name, new_test_table, new_test_keyspace, new_function, new_aggregate, new_cql
+from cassandra.protocol import InvalidRequest
 
 # (`element` refers to keyspace or keyspace's element(table, type, function, aggregate))
 # There are 2 main types of tests:
@@ -459,6 +460,16 @@ def test_generic_desc(cql, random_seed):
             assert generic_tbl == desc_tbl
             assert generic_idx == desc_idx
 
+# Test that 'DESC FUNCTION'/'DESC AGGREGATE' doesn't show UDA/UDF and doesn't crash Scylla
+def test_desc_udf_uda(cql, test_keyspace):
+    with new_function(cql, test_keyspace, "(a int, b int) RETURNS NULL ON NULL INPUT RETURNS int LANGUAGE LUA AS 'return a+b'") as fn:
+        with new_aggregate(cql, test_keyspace, f"(int) SFUNC {fn} STYPE int") as aggr:
+
+            with pytest.raises(InvalidRequest):
+                cql.execute(f"DESC FUNCTION {test_keyspace}.{aggr}")
+            with pytest.raises(InvalidRequest):
+                cql.execute(f"DESC AGGREGATE {test_keyspace}.{fn}")
+
 # -----------------------------------------------------------------------------
 # Following tests `test_*_quoting` check if names inside elements' descriptions are quoted if needed.
 # The tests don't check if create statements are correct, but only assert if the name inside is quoted.