Only validate primary ids on release branches

build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/transport/AbstractTransportVersionFuncTest.groovy

@@ -125,6 +125,9 @@ class AbstractTransportVersionFuncTest extends AbstractGradleFuncTest {
             tasks.named('generateTransportVersion') {
                 currentUpperBoundName = '9.2'
             }
+            tasks.named('validateTransportVersionResources') {
+                currentUpperBoundName = '9.2'
+            }
         """
         referableAndReferencedTransportVersion("existing_91", "8012000")
         referableAndReferencedTransportVersion("older_92", "8122000")

build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/transport/TransportVersionValidationFuncTest.groovy

@@ -277,4 +277,21 @@ class TransportVersionValidationFuncTest extends AbstractTransportVersionFuncTes
             "[myserver/src/main/resources/transport/definitions/referable/existing_92.csv]"
         )
     }
+
+    def "primary id checks skipped on release branch"() {
+        given:
+        file("myserver/build.gradle") << """
+            tasks.named('validateTransportVersionResources') {
+                currentUpperBoundName = '9.1'
+            }
+        """
+        referableAndReferencedTransportVersion("some_tv", "8125000")
+        transportVersionUpperBound("9.2", "some_tv", "8125000")
+
+        when:
+        def result = gradleRunner("validateTransportVersionResources").build()
+
+        then:
+        result.task(":myserver:validateTransportVersionResources").outcome == TaskOutcome.SUCCESS
+    }
 }

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

@@ -70,6 +70,7 @@ public void apply(Project project) {
                 t.getReferencesFiles().setFrom(tvReferencesConfig);
                 t.getShouldValidateDensity().convention(true);
                 t.getShouldValidatePrimaryIdNotPatch().convention(true);
+                t.getCurrentUpperBoundName().convention(currentVersion.getMajor() + "." + currentVersion.getMinor());
             });
         project.getTasks().named(PrecommitPlugin.PRECOMMIT_TASK_NAME).configure(t -> t.dependsOn(validateTask));
 

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

@@ -60,6 +60,13 @@ public Path getResourcesDir() {
     @Input
     public abstract Property<Boolean> getShouldValidatePrimaryIdNotPatch();
 
+    /**
+     * The name of the upper bounds file which will be used at runtime on the current branch. Normally
+     * this equates to VersionProperties.getElasticsearchVersion().
+     */
+    @Input
+    public abstract Property<String> getCurrentUpperBoundName();
+
     private record IdAndDefinition(TransportVersionId id, TransportVersionDefinition definition) {}
 
     private static final Pattern NAME_FORMAT = Pattern.compile("[a-z0-9_]+");
@@ -76,6 +83,7 @@ public void validateTransportVersions() throws IOException {
         Map<String, TransportVersionDefinition> allDefinitions = collectAllDefinitions(referableDefinitions, unreferableDefinitions);
         Map<Integer, List<IdAndDefinition>> idsByBase = collectIdsByBase(allDefinitions.values());
         Map<String, TransportVersionUpperBound> upperBounds = resources.getUpperBounds();
+        boolean onReleaseBranch = checkIfDefinitelyOnReleaseBranch(upperBounds);
 
         for (var definition : referableDefinitions.values()) {
             validateNamedDefinition(definition, referencedNames);
@@ -93,7 +101,9 @@ public void validateTransportVersions() throws IOException {
             validateUpperBound(upperBound, allDefinitions, idsByBase);
         }
 
-        validatePrimaryIds(resources, upperBounds, allDefinitions);
+        if (onReleaseBranch == false) {
+            validatePrimaryIds(resources, upperBounds, allDefinitions);
+        }
     }
 
     private Map<String, TransportVersionDefinition> collectAllDefinitions(
@@ -318,6 +328,22 @@ private void validatePrimaryIds(
         );
     }
 
+    private boolean checkIfDefinitelyOnReleaseBranch(Map<String, TransportVersionUpperBound> upperBounds) {
+        // only want to look at definitions <= the current upper bound.
+        // TODO: we should filter all of the upper bounds/definitions that are validated by this, not just in this method
+        String currentUpperBoundName = getCurrentUpperBoundName().get();
+        TransportVersionUpperBound currentUpperBound = upperBounds.get(currentUpperBoundName);
+
+        // non-main branches
+        for (TransportVersionUpperBound upperBound : upperBounds.values()) {
+            if (upperBound.definitionId().complete() > currentUpperBound.definitionId().complete()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     private void throwDefinitionFailure(TransportVersionDefinition definition, String message) {
         Path relativePath = getResources().get().getDefinitionPath(definition);
         throw new VerificationException("Transport version definition file [" + relativePath + "] " + message);