NIFI-16276 fix: Updating process group version should not clear parameter context

nifi-framework-bundle/nifi-framework/nifi-framework-components/src/main/java/org/apache/nifi/flow/synchronization/StandardVersionedComponentSynchronizer.java

@@ -2193,9 +2193,9 @@ private void updateParameterContext(final ProcessGroup group, final VersionedPro
         // Update the Parameter Context
         final ParameterContext currentParamContext = group.getParameterContext();
         final String proposedParameterContextName = proposed.getParameterContextName();
-        if (proposedParameterContextName == null && currentParamContext != null) {
-            group.setParameterContext(null);
-        } else if (proposedParameterContextName != null) {
+        // A group's own versioned definition may never carry a Parameter Context if it's meant to be bound locally by
+        // whatever parent embeds it, so a null name here must not clear an existing binding.
+        if (proposedParameterContextName != null) {
             final VersionedParameterContext versionedParameterContext = versionedParameterContexts.get(proposedParameterContextName);
             if (versionedParameterContext != null) {
                 createMissingParameterProvider(versionedParameterContext, versionedParameterContext.getParameterProvider(), parameterProviderReferences, componentIdGenerator);

nifi-framework-bundle/nifi-framework/nifi-framework-components/src/test/java/org/apache/nifi/flow/synchronization/StandardVersionedComponentSynchronizerTest.java

@@ -1792,6 +1792,39 @@ public void testUpdateParameterContextWhenContextDoesExist() {
         verify(processGroup, times(1)).setParameterContext(any(ParameterContext.class));
     }
 
+    @Test
+    public void testLocallyAssignedParameterContextPreservedWhenChildGroupUpdatedFromOwnStandaloneVersion() {
+        // Updating a child group directly to its own standalone version, which never declared a Parameter Context, must not clear a Parameter Context locally assigned to it by a parent.
+        final ProcessGroup processGroup = mock(ProcessGroup.class);
+        when(processGroup.getIdentifier()).thenReturn("pg1");
+        when(processGroup.getPosition()).thenReturn(new org.apache.nifi.connectable.Position(0, 0));
+        when(processGroup.getFlowFileConcurrency()).thenReturn(FlowFileConcurrency.UNBOUNDED);
+        when(processGroup.getFlowFileOutboundPolicy()).thenReturn(FlowFileOutboundPolicy.BATCH_OUTPUT);
+        when(processGroup.getExecutionEngine()).thenReturn(ExecutionEngine.STANDARD);
+
+        // A Parameter Context already bound to the child group, simulating a parent's local assignment.
+        final ParameterContext existingParameterContext = new StandardParameterContext.Builder()
+            .id("existing-pc")
+            .name("HTTP ReceiverB")
+            .parameterReferenceManager(parameterReferenceManager)
+            .build();
+        when(processGroup.getParameterContext()).thenReturn(existingParameterContext);
+
+        // The child group's own standalone versioned flow definition never had a Parameter Context of its own.
+        final VersionedProcessGroup rootGroup = new VersionedProcessGroup();
+        rootGroup.setIdentifier("pg1");
+        rootGroup.setParameterContextName(null);
+
+        final VersionedExternalFlow externalFlow = new VersionedExternalFlow();
+        externalFlow.setFlowContents(rootGroup);
+        externalFlow.setParameterContexts(Collections.emptyMap());
+
+        synchronizer.synchronize(processGroup, externalFlow, synchronizationOptions);
+
+        // The locally-assigned Parameter Context must survive the update.
+        verify(processGroup, never()).setParameterContext(null);
+    }
+
     @Test
     public void testNewParameterInInheritedContextAddedDuringSync() throws FlowSynchronizationException, InterruptedException, TimeoutException {
         // Create P2 with paramA

nifi-system-tests/nifi-system-test-suite/src/test/java/org/apache/nifi/tests/system/NiFiClientUtil.java

@@ -1154,7 +1154,10 @@ private ParameterContextReferenceEntity createReferenceEntity(final String id, f
 
     public ProcessGroupEntity setParameterContext(final String groupId, final ParameterContextEntity parameterContext) throws NiFiClientException, IOException {
         final ProcessGroupEntity processGroup = nifiClient.getProcessGroupClient().getProcessGroup(groupId);
-        processGroup.getComponent().setParameterContext(createReferenceEntity(parameterContext.getId()));
+        ProcessGroupDTO component = new ProcessGroupDTO();
+        component.setId(processGroup.getId());
+        component.setParameterContext(createReferenceEntity(parameterContext.getId()));
+        processGroup.setComponent(component);
         return nifiClient.getProcessGroupClient().updateProcessGroup(processGroup);
     }
 

nifi-system-tests/nifi-system-test-suite/src/test/java/org/apache/nifi/tests/system/registry/ParameterContextPreservationIT.java

@@ -601,4 +601,41 @@ void testApplyParameterContextRecursivelyAcrossVersionedDescendant() throws NiFi
         assertNotNull(childAfterUpdate.getComponent().getVersionControlInformation(),
                 "Versioned child Process Group should remain under version control after a recursive Parameter Context change");
     }
+
+    /**
+     * Verifies that a Parameter Context locally assigned to a shared, independently version-controlled child Process Group survives a version upgrade of that child.
+     */
+    @Test
+    void testLocallyAssignedParameterContextPreservedWhenVersionedChildUpgraded() throws NiFiClientException, IOException, InterruptedException {
+        final FlowRegistryClientEntity clientEntity = registerClient();
+        final NiFiClientUtil util = getClientUtil();
+
+        final ParameterContextEntity locallyAssignedContext = util.createParameterContext("locally-assigned-context", Map.of(PARAMETER_NAME, PARAMETER_VALUE));
+
+        // Shared child Process Group, version-controlled on its own, deliberately without a Parameter Context of its own.
+        final ProcessGroupEntity versionedGroup = util.createProcessGroup("shared-utility", "root");
+        //util.setParameterContext(versionedGroup.getId(), emptyContext);
+        final VersionControlInformationEntity childVciV1 = util.startVersionControl(versionedGroup, clientEntity, TEST_FLOWS_BUCKET, "SharedUtility");
+
+        final ProcessGroupEntity instance = util.importFlowFromRegistry("root", childVciV1.getVersionControlInformation());
+
+        // Assign a Parameter Context to the child locally, outside its own versioned definition.
+        util.setParameterContext(instance.getId(), locallyAssignedContext);
+
+        // Modify the child's own definition and commit version 2 so there's a newer version to upgrade to.
+        final ProcessorEntity processor = util.createProcessor(PROCESSOR_TYPE, versionedGroup.getId());
+        util.setAutoTerminatedRelationships(processor, RELATIONSHIP_SUCCESS);
+        final ProcessGroupEntity refreshedChildGroup = getNifiClient().getProcessGroupClient().getProcessGroup(versionedGroup.getId());
+        util.saveFlowVersion(refreshedChildGroup, clientEntity, childVciV1);
+
+        // Update the child directly to version 2, fetching its own standalone snapshot which still declares no Parameter Context.
+        util.changeFlowVersion(instance.getId(), VERSION_2);
+
+        final ProcessGroupEntity instanceAfterUpgrade = getNifiClient().getProcessGroupClient().getProcessGroup(instance.getId());
+        assertEquals(VERSION_2, instanceAfterUpgrade.getComponent().getVersionControlInformation().getVersion());
+        assertNotNull(instanceAfterUpgrade.getComponent().getParameterContext(),
+                "Parameter Context locally assigned to the child should survive the version upgrade");
+        assertEquals(locallyAssignedContext.getId(), instanceAfterUpgrade.getComponent().getParameterContext().getId(),
+                "Child Process Group should remain bound to the locally-assigned Parameter Context after upgrading to a new version");
+    }
 }