Apply suggestions from code review

Co-authored-by: Adrian Garcia Badaracco <1755071+adriangb@users.noreply.github.com>

Author: adriangb

datafusion/physical-expr/src/expressions/like.rs

@@ -347,12 +347,7 @@ mod test {
     }
 }
 
-/// Tests for the `try_to_proto` / `try_from_proto` hooks (issue #22418).
-///
-/// These drive the encode/decode hooks directly with small stub
-/// encoder/decoders so every branch can be covered without depending on
-/// `datafusion-proto`: the happy path, the wrong-node and missing-child
-/// rejections, and child encode/decode error propagation.
+/// Tests for the `try_to_proto` / `try_from_proto` hooks.
 #[cfg(all(test, feature = "proto"))]
 mod proto_tests {
     use super::*;

datafusion/physical-expr/src/lib.rs

@@ -40,8 +40,7 @@ mod partitioning;
 mod physical_expr;
 pub mod planner;
 pub mod projection;
-/// Shared test helpers for the `try_to_proto` / `try_from_proto` migration
-/// (issue #22418). Compiled only under `cfg(test)` with the `proto` feature.
+/// Shared test helpers for the `try_to_proto` / `try_from_proto` unit tests
 #[cfg(all(test, feature = "proto"))]
 pub(crate) mod proto_test_util;
 mod scalar_function;

datafusion/physical-expr/src/proto_test_util.rs

@@ -15,15 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//! Shared test helpers for exercising the `try_to_proto` / `try_from_proto`
-//! hooks (issue #22418) without depending on `datafusion-proto`.
-//!
-//! As built-in expressions are ported off the central proto downcast chain,
-//! each one's unit tests need to drive the new encode/decode hooks in
-//! isolation. The generic scaffolding — stub encoder/decoders and a
-//! placeholder child-node builder — lives here so it is written once and
-//! reused across expressions. Expression-specific node builders and fixtures
-//! stay in each expression's own test module.
+//! Shared test helpers for proto serialization / deserialization in expression unit tests
+//! without depending on `datafusion-proto` (which would create circular deps).
 
 use std::cell::Cell;
 use std::sync::Arc;