Merge branch 'main' into fix-false-allow-templates-edge-case

Signed-off-by: Bruce Hong <bruce.hong@glean.com>

Author: bruce-hong-glean

CHANGELOG.md

@@ -19,6 +19,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Fix NullPointerException in segment replicator ([#18997](https://github.com/opensearch-project/OpenSearch/pull/18997))
 - Ensure that plugins that utilize dumpCoverage can write to jacoco.dir when tests.security.manager is enabled ([#18983](https://github.com/opensearch-project/OpenSearch/pull/18983))
 - Fix OOM due to large number of shard result buffering ([#19066](https://github.com/opensearch-project/OpenSearch/pull/19066))
+- Fix flaky tests in CloseIndexIT by addressing cluster state synchronization issues ([#18878](https://github.com/opensearch-project/OpenSearch/issues/18878))
+- [Tiered Caching] Handle  query execution exception ([#19000](https://github.com/opensearch-project/OpenSearch/issues/19000))
+- Grant access to testclusters dir for tests ([#19085](https://github.com/opensearch-project/OpenSearch/issues/19085))
 - Throw error when unrecognized content token type is being indexed ([#19097](https://github.com/opensearch-project/OpenSearch/pull/19097))
 
 ### Dependencies
@@ -35,10 +38,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Removed
 - Enable backward compatibility tests on Mac ([#18983](https://github.com/opensearch-project/OpenSearch/pull/18983))
 
-### Fixed
-- Fix flaky tests in CloseIndexIT by addressing cluster state synchronization issues ([#18878](https://github.com/opensearch-project/OpenSearch/issues/18878))
-- [Tiered Caching] Handle  query execution exception ([#19000](https://github.com/opensearch-project/OpenSearch/issues/19000))
-
 ### Security
 
 [Unreleased 3.x]: https://github.com/opensearch-project/OpenSearch/compare/3.1...main

test/framework/src/main/java/org/opensearch/bootstrap/BootstrapForTesting.java

@@ -158,6 +158,16 @@ public class BootstrapForTesting {
                         false
                     );
                 }
+                String testclustersDir = System.getProperty("testclusters.dir");
+                if (testclustersDir != null) {
+                    FilePermissionUtils.addDirectoryPath(
+                        perms,
+                        "testclusters.dir",
+                        PathUtils.get(testclustersDir),
+                        "read,readlink,write,delete",
+                        false
+                    );
+                }
                 // custom test config file
                 String testConfigFile = System.getProperty("tests.config");
                 if (Strings.hasLength(testConfigFile)) {