codewide: introduce DeserializeOwned{Row,Value}

As noted in a review comment, parsing `for<'r> DeserializeValue<'r, 'r>`
to understand it's requiring an owned type is nontrivial and could be
replaced with a subtrait with an informative name.
Therefore, this commit introduces DeserializeOwnedRow and
DeserializeOwnedValue (to be used by the `scylla` crate itself only).

scylla/src/lib.rs

@@ -230,6 +230,13 @@ pub mod deserialize {
             UdtIterator, UdtTypeCheckErrorKind,
         };
     }
+
+    // Shorthands for better readability.
+    #[cfg_attr(not(test), allow(unused))]
+    pub(crate) trait DeserializeOwnedValue: for<'r> DeserializeValue<'r, 'r> {}
+    impl<T> DeserializeOwnedValue for T where T: for<'r> DeserializeValue<'r, 'r> {}
+    pub(crate) trait DeserializeOwnedRow: for<'r> DeserializeRow<'r, 'r> {}
+    impl<T> DeserializeOwnedRow for T where T: for<'r> DeserializeRow<'r, 'r> {}
 }
 
 pub mod authentication;

scylla/src/transport/cql_collections_test.rs

@@ -1,5 +1,5 @@
+use crate::deserialize::DeserializeOwnedValue;
 use crate::transport::session::Session;
-use scylla_cql::types::deserialize::value::DeserializeValue;
 
 use crate::frame::response::result::CqlValue;
 use crate::test_utils::{create_new_session_builder, setup_tracing};
@@ -36,7 +36,7 @@ async fn insert_and_select<InsertT, SelectT>(
     expected: &SelectT,
 ) where
     InsertT: SerializeValue,
-    SelectT: for<'r> DeserializeValue<'r, 'r> + PartialEq + std::fmt::Debug,
+    SelectT: DeserializeOwnedValue + PartialEq + std::fmt::Debug,
 {
     session
         .query_unpaged(

scylla/src/transport/cql_types_test.rs

@@ -1,12 +1,12 @@
 use crate as scylla;
+use crate::deserialize::DeserializeOwnedValue;
 use crate::frame::response::result::CqlValue;
 use crate::frame::value::{Counter, CqlDate, CqlTime, CqlTimestamp};
 use crate::test_utils::{create_new_session_builder, scylla_supports_tablets, setup_tracing};
 use crate::transport::session::Session;
 use crate::utils::test_utils::unique_keyspace_name;
 use itertools::Itertools;
 use scylla_cql::frame::value::{CqlTimeuuid, CqlVarint};
-use scylla_cql::types::deserialize::value::DeserializeValue;
 use scylla_cql::types::serialize::value::SerializeValue;
 use scylla_macros::{DeserializeValue, SerializeValue};
 use std::cmp::PartialEq;
@@ -74,7 +74,7 @@ async fn init_test(table_name: &str, type_name: &str) -> Session {
 // Expected values and bound values are computed using T::from_str
 async fn run_tests<T>(tests: &[&str], type_name: &str)
 where
-    T: SerializeValue + for<'r> DeserializeValue<'r, 'r> + FromStr + Debug + Clone + PartialEq,
+    T: SerializeValue + DeserializeOwnedValue + FromStr + Debug + Clone + PartialEq,
 {
     let session: Session = init_test(type_name, type_name).await;
     session.await_schema_agreement().await.unwrap();
@@ -1799,7 +1799,7 @@ async fn test_udt_with_missing_field() {
         expected: TR,
     ) where
         TQ: SerializeValue,
-        TR: for<'r> DeserializeValue<'r, 'r> + PartialEq + Debug,
+        TR: DeserializeOwnedValue + PartialEq + Debug,
     {
         session
             .query_unpaged(

scylla/src/transport/iterator.rs

@@ -24,6 +24,7 @@ use super::query_result::ColumnSpecs;
 use super::session::RequestSpan;
 use crate::cql_to_rust::{FromRow, FromRowError};
 
+use crate::deserialize::DeserializeOwnedRow;
 use crate::frame::response::{
     result,
     result::{ColumnSpec, Row},
@@ -1076,7 +1077,7 @@ impl<RowT> TypedRowStream<RowT> {
 /// It only works with owned types! For example, &str is not supported.
 impl<RowT> Stream for TypedRowStream<RowT>
 where
-    RowT: for<'r> DeserializeRow<'r, 'r>,
+    RowT: DeserializeOwnedRow,
 {
     type Item = Result<RowT, QueryError>;
 

scylla/src/transport/session_test.rs

@@ -1,5 +1,5 @@
 use crate::batch::{Batch, BatchStatement};
-use crate::deserialize::DeserializeValue;
+use crate::deserialize::DeserializeOwnedValue;
 use crate::prepared_statement::PreparedStatement;
 use crate::query::Query;
 use crate::retry_policy::{QueryInfo, RetryDecision, RetryPolicy, RetrySession};
@@ -3100,7 +3100,7 @@ async fn test_deserialize_empty_collections() {
     session.use_keyspace(&ks, true).await.unwrap();
 
     async fn deserialize_empty_collection<
-        Collection: Default + for<'frame> DeserializeValue<'frame, 'frame> + SerializeValue,
+        Collection: Default + DeserializeOwnedValue + SerializeValue,
     >(
         session: &Session,
         collection_name: &str,

scylla/src/transport/topology.rs

@@ -1,3 +1,4 @@
+use crate::deserialize::DeserializeOwnedRow;
 use crate::frame::response::event::Event;
 use crate::routing::Token;
 use crate::statement::query::Query;
@@ -15,7 +16,6 @@ use futures::Stream;
 use rand::seq::SliceRandom;
 use rand::{thread_rng, Rng};
 use scylla_cql::frame::frame_errors::RowsParseError;
-use scylla_cql::types::deserialize::row::DeserializeRow;
 use scylla_cql::types::deserialize::TypeCheckError;
 use scylla_macros::DeserializeRow;
 use std::borrow::BorrowMut;
@@ -930,7 +930,7 @@ fn query_filter_keyspace_name<'a, R>(
     convert_typecheck_error: impl FnOnce(TypeCheckError) -> MetadataError + 'a,
 ) -> impl Stream<Item = Result<R, QueryError>> + 'a
 where
-    R: for<'r> DeserializeRow<'r, 'r> + 'static,
+    R: DeserializeOwnedRow + 'static,
 {
     let conn = conn.clone();