only check latest files on main or current branch

Author: rjernst

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/transport/ValidateTransportVersionDefinitionsTask.java

@@ -11,6 +11,8 @@
 
 import com.google.common.collect.Comparators;
 
+import org.elasticsearch.gradle.Version;
+import org.elasticsearch.gradle.VersionProperties;
 import org.elasticsearch.gradle.internal.transport.TransportVersionUtils.TransportVersionDefinition;
 import org.elasticsearch.gradle.internal.transport.TransportVersionUtils.TransportVersionId;
 import org.elasticsearch.gradle.internal.transport.TransportVersionUtils.TransportVersionLatest;
@@ -128,11 +130,36 @@ public void validateTransportVersions() throws IOException {
 
         // now load all latest versions and do validation
         // NOTE: this must run after definition recording and idsByBase cleanup
+        List<Path> latestFiles = new ArrayList<>();
         try (var latestStream = Files.list(latestDir)) {
             for (var latestFile : latestStream.toList()) {
-                recordAndValidateLatest(readLatestFile(latestFile));
+                latestFiles.add(latestFile);
             }
         }
+        if (latestFiles.size() > 1) {
+            // only check all files on main, otherwise just check the current major/minor version
+            // NOTE: this implicitly works for serverless because it only has one version so we skip parsing
+            Version currentVersion = VersionProperties.getElasticsearchVersion();
+            boolean onMain = true;
+            for (Path latestFile : latestFiles) {
+                String[] branchParts = latestFile.getFileName().toString().split("\\.");
+                int major = Integer.parseInt(branchParts[0]);
+                int minor = Integer.parseInt(branchParts[1]);
+                if (major > currentVersion.getMajor() || major == currentVersion.getMajor() && minor > currentVersion.getMinor()) {
+                    onMain = false;
+                    break;
+                }
+            }
+
+            if (onMain == false) {
+                String currentBranch = currentVersion.getMajor() + "." + currentVersion.getMinor();
+                latestFiles = List.of(TransportVersionUtils.latestFilePath(getResourcesDirectory().get(), currentBranch));
+            }
+        }
+        for (Path latestFile : latestFiles) {
+            recordAndValidateLatest(readLatestFile(latestFile));
+        }
+
     }
 
     private String gitCommand(String... args) {