remove release note section; mark patched code in PatchedProtoWriteSupport

Author: khaledh

docs/content/release-notes/flink-2.1.md

@@ -183,26 +183,3 @@ Bump flink-shaded version to 20.0 to support Smile format.
 
 Bump parquet version to 1.15.3 to resolve parquet-avro module
 vulnerability found in [CVE-2025-30065](https://nvd.nist.gov/vuln/detail/CVE-2025-30065).
-
-#### Upgrade Protocol Buffers to 4.32.1
-
-##### [FLINK-38547](https://issues.apache.org/jira/browse/FLINK-38547)
-
-Flink now uses protobuf-java 4.32.1 (corresponding to Protocol Buffers version 32), upgrading from
-protobuf-java 3.21.7 (Protocol Buffers version 21). This major upgrade enables:
-
-- **Protobuf Editions Support**: Full support for the new `edition = "2023"` and `edition = "2024"`
-  syntax introduced in Protocol Buffers v27+. Editions provide a unified approach that combines
-  proto2 and proto3 functionality with fine-grained feature control.
-- **Improved Proto3 Field Presence**: Better handling of optional fields in proto3 without the
-  limitations of older protobuf versions, eliminating the need to set `protobuf.read-default-values`
-  to `true` for field presence checking.
-- **Enhanced Performance**: Leverages performance improvements and bug fixes from 11 Protocol
-  Buffers releases (versions 22-32).
-- **Modern Protobuf Features**: Access to newer protobuf capabilities including Edition 2024
-  features and improved runtime behavior.
-
-Users with existing proto2 and proto3 `.proto` files will continue to work without changes. For
-those interested in adopting Protobuf Editions, see the updated
-[Protobuf format documentation](https://nightlies.apache.org/flink/flink-docs-release-2.1/docs/connectors/table/formats/protobuf/)
-for examples and guidance.

flink-formats/flink-parquet/src/main/java/org/apache/flink/formats/parquet/protobuf/PatchedProtoWriteSupport.java

@@ -79,6 +79,8 @@
  *
  * <p>The original source can be found here:
  * https://github.com/apache/parquet-java/blob/apache-parquet-1.15.2/parquet-protobuf/src/main/java/org/apache/parquet/proto/ProtoWriteSupport.java
+ *
+ * <p>Patched code is marked with BEGIN PATCH / END PATCH comments in the source.
  */
 class PatchedProtoWriteSupport<T extends MessageOrBuilder> extends WriteSupport<T> {
 
@@ -469,7 +471,9 @@ final void writeField(Object value) {
 
         private void writeAllFields(MessageOrBuilder pb) {
             Descriptor messageDescriptor = pb.getDescriptorForType();
-            // PATCH: Use string-based syntax detection instead of enum (protobuf 4.x compatibility)
+            // ============================================================================
+            // BEGIN PATCH: Replace enum-based syntax detection with string-based approach
+            // ============================================================================
             String syntax = messageDescriptor.getFile().toProto().getSyntax();
 
             // Check for editions syntax (not supported)
@@ -482,6 +486,9 @@ private void writeAllFields(MessageOrBuilder pb) {
             boolean isProto2 = syntax.isEmpty() || "proto2".equals(syntax);
 
             if (isProto2) {
+                // ============================================================================
+                // END PATCH
+                // ============================================================================
                 // Returns changed fields with values. Map is ordered by id.
                 Map<FieldDescriptor, Object> changedPbFields = pb.getAllFields();