From 0eb7d3e90a440b5b631e61387d5690f947d83034 Mon Sep 17 00:00:00 2001
From: Benjamin Trent <benjamin.trent@elastic.co>
Date: Thu, 28 Oct 2021 15:55:50 -0400
Subject: [PATCH] [ML] fixing MlMetadata backwards compatibility with 7.x
 (#80041)

Since 7.13, MlMetadata with reset mode has been serializable. But, this
was never adjusted in the 8.0.0 branch. This commit fixes a
serialization bug currently present in alpha + beta1 releases of
Elasticsearch 8.0.0. When MlMetadata exists in a cluster, a rolling
upgrade, or mixed-version environment may fail to serialize cluster
state between 8.0.0 nodes and nodes 7.13-7.16
---
 .../java/org/elasticsearch/xpack/core/ml/MlMetadata.java  | 8 ++++----
 .../xpack/core/ml/inference/TrainedModelConfig.java       | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/MlMetadata.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/MlMetadata.java
index ed605f4fea43c..1c79ec8bd9819 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/MlMetadata.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/MlMetadata.java
@@ -162,7 +162,7 @@ public MlMetadata(StreamInput in) throws IOException {
         this.datafeeds = datafeeds;
         this.groupOrJobLookup = new GroupOrJobLookup(jobs.values());
         this.upgradeMode = in.readBoolean();
-        if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_7_13_0)) {
             this.resetMode = in.readBoolean();
         } else {
             this.resetMode = false;
@@ -174,7 +174,7 @@ public void writeTo(StreamOutput out) throws IOException {
         writeMap(jobs, out);
         writeMap(datafeeds, out);
         out.writeBoolean(upgradeMode);
-        if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_7_13_0)) {
             out.writeBoolean(resetMode);
         }
     }
@@ -240,7 +240,7 @@ public MlMetadataDiff(StreamInput in) throws IOException {
                 MlMetadataDiff::readDatafeedDiffFrom
             );
             upgradeMode = in.readBoolean();
-            if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (in.getVersion().onOrAfter(Version.V_7_13_0)) {
                 resetMode = in.readBoolean();
             } else {
                 resetMode = false;
@@ -264,7 +264,7 @@ public void writeTo(StreamOutput out) throws IOException {
             jobs.writeTo(out);
             datafeeds.writeTo(out);
             out.writeBoolean(upgradeMode);
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (out.getVersion().onOrAfter(Version.V_7_13_0)) {
                 out.writeBoolean(resetMode);
             }
         }
diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
index cad6a3668c223..5e9efc658ab7c 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
@@ -885,7 +885,7 @@ public static LazyModelDefinition fromBase64String(String base64String) {
         }
 
         public static LazyModelDefinition fromStreamInput(StreamInput input) throws IOException {
-            if (input.getVersion().onOrAfter(Version.V_8_0_0)) { // TODO adjust on backport
+            if (input.getVersion().onOrAfter(Version.V_8_0_0)) {
                 return new LazyModelDefinition(input.readBytesReference(), null);
             } else {
                 return fromBase64String(input.readString());
@@ -949,7 +949,7 @@ private void ensureParsedDefinitionUnsafe(NamedXContentRegistry xContentRegistry
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) { // TODO adjust on backport
+            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
                 out.writeBytesReference(getCompressedDefinition());
             } else {
                 out.writeString(getBase64CompressedDefinition());