From 9087fc5de8ecbe96158cb7ce654c968be6b965eb Mon Sep 17 00:00:00 2001
From: Max Hniebergall <137079448+maxhniebergall@users.noreply.github.com>
Date: Wed, 3 Jul 2024 11:59:16 -0400
Subject: [PATCH] [Inference API] Fix serialization for inference delete
 endpoint response (#110431)

---
 docs/changelog/110431.yaml                             |  5 +++++
 .../action/DeleteInferenceEndpointAction.java          | 10 ++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 docs/changelog/110431.yaml

diff --git a/docs/changelog/110431.yaml b/docs/changelog/110431.yaml
new file mode 100644
index 0000000000000..0dd93ef718ef9
--- /dev/null
+++ b/docs/changelog/110431.yaml
@@ -0,0 +1,5 @@
+pr: 110431
+summary: "[Inference API] Fix serialization for inference delete endpoint response"
+area: Machine Learning
+type: bug
+issues: []
diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceEndpointAction.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceEndpointAction.java
index 19542ef466156..dfb77ccd49fc2 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceEndpointAction.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceEndpointAction.java
@@ -113,13 +113,19 @@ public Response(boolean acknowledged, Set<String> pipelineIds) {
 
         public Response(StreamInput in) throws IOException {
             super(in);
-            pipelineIds = in.readCollectionAsSet(StreamInput::readString);
+            if (in.getTransportVersion().onOrAfter(TransportVersions.ML_INFERENCE_ENHANCE_DELETE_ENDPOINT)) {
+                pipelineIds = in.readCollectionAsSet(StreamInput::readString);
+            } else {
+                pipelineIds = Set.of();
+            }
         }
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             super.writeTo(out);
-            out.writeCollection(pipelineIds, StreamOutput::writeString);
+            if (out.getTransportVersion().onOrAfter(TransportVersions.ML_INFERENCE_ENHANCE_DELETE_ENDPOINT)) {
+                out.writeCollection(pipelineIds, StreamOutput::writeString);
+            }
         }
 
         @Override