NIFI-4436: Bug fixes - Checkpoint before allowing multiple Process Groups with same Versioned Component ID and same parent - Ensure that if flow update is cancelled while processors are being stopped/services disabled that we stop waiting for that to occur. Also ensure that if we fail to update flow that we re-enable/restart the processors and services - Updated verbiage to use a ConciseEvolvingDifferentDescriptor when getting local modifications for a versioned flow - Do not allow outer process group to be saved to flow registry or have local modifications reverted if it has a descendant process group that is under version control and is dirty. Fixed bug where ComponentDifferenceDTO was populated with wrong component id and group id

Signed-off-by: Matt Gilman <matt.c.gilman@gmail.com>

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-client-dto/src/main/java/org/apache/nifi/web/api/entity/VersionedFlowSnapshotEntity.java

@@ -28,6 +28,7 @@ public class VersionedFlowSnapshotEntity extends Entity {
     private VersionedFlowSnapshot versionedFlowSnapshot;
     private RevisionDTO processGroupRevision;
     private String registryId;
+    private Boolean updateDescendantVersionedFlows;
 
     @ApiModelProperty("The versioned flow snapshot")
     public VersionedFlowSnapshot getVersionedFlowSnapshot() {
@@ -55,4 +56,14 @@ public class VersionedFlowSnapshotEntity extends Entity {
     public void setRegistryId(String registryId) {
         this.registryId = registryId;
     }
+
+    @ApiModelProperty("If the Process Group to be updated has a child or descendant Process Group that is also under "
+        + "Version Control, this specifies whether or not the contents of that child/descendant Process Group should be updated.")
+    public Boolean getUpdateDescendantVersionedFlows() {
+        return updateDescendantVersionedFlows;
+    }
+
+    public void setUpdateDescendantVersionedFlows(Boolean update) {
+        this.updateDescendantVersionedFlows = update;
+    }
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core-api/src/main/java/org/apache/nifi/groups/ProcessGroup.java

@@ -784,8 +784,10 @@ public interface ProcessGroup extends ComponentAuthorizable, Positionable, Versi
      *            and the Process Group has been modified since it was last synchronized with the Flow Registry, then this method will
      *            throw an IllegalStateException
      * @param updateSettings whether or not to update the process group's name and positions
+     * @param updateDescendantVersionedFlows if a child/descendant Process Group is under Version Control, specifies whether or not to
+     *            update the contents of that Process Group
      */
-    void updateFlow(VersionedFlowSnapshot proposedSnapshot, String componentIdSeed, boolean verifyNotDirty, boolean updateSettings);
+    void updateFlow(VersionedFlowSnapshot proposedSnapshot, String componentIdSeed, boolean verifyNotDirty, boolean updateSettings, boolean updateDescendantVersionedFlows);
 
     /**
      * Verifies a template with the specified name can be created.
@@ -848,7 +850,7 @@ public interface ProcessGroup extends ComponentAuthorizable, Positionable, Versi
     void verifyCanUpdateVariables(Map<String, String> updatedVariables);
 
     /**
-     * Ensure that the contents of the Process Group can be update to match the given new flow
+     * Ensures that the contents of the Process Group can be update to match the given new flow
      *
      * @param updatedFlow the updated version of the flow
      * @param verifyConnectionRemoval whether or not to verify that connections that are not present in the updated flow can be removed
@@ -859,6 +861,27 @@ public interface ProcessGroup extends ComponentAuthorizable, Positionable, Versi
      */
     void verifyCanUpdate(VersionedFlowSnapshot updatedFlow, boolean verifyConnectionRemoval, boolean verifyNotDirty);
 
+    /**
+     * Ensures that the Process Group can have any local changes reverted
+     *
+     * @throws IllegalStateException if the Process Group is not in a state that will allow local changes to be reverted
+     */
+    void verifyCanRevertLocalModifications();
+
+    /**
+     * Ensures that the Process Group can have its local modifications shown
+     *
+     * @throws IllegalStateException if the Process Group is not in a state that will allow local modifications to be shown
+     */
+    void verifyCanShowLocalModifications();
+
+    /**
+     * Ensure that the contents of the Process Group can be saved to a Flow Registry in its current state
+     *
+     * @throws IllegalStateException if the Process Group cannot currently be saved to a Flow Registry
+     */
+    void verifyCanSaveToFlowRegistry(String registryId, String bucketId, String flowId);
+
     /**
      * Adds the given template to this Process Group
      *

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core-api/src/main/java/org/apache/nifi/registry/flow/FlowRegistry.java

@@ -159,6 +159,9 @@ public interface FlowRegistry {
      * @param bucketId the ID of the bucket
      * @param flowId the ID of the flow
      * @param version the version to retrieve
+     * @param fetchRemoteFlows if the remote flow has a child Process Group that also tracks to a remote flow, this specifies whether or not
+     *            the child's contents should be fetched.
+     * @param user the user on whose behalf the flow contents are being retrieved
      * @return the contents of the Flow from the Flow Registry
      *
      * @throws IOException if unable to communicate with the Flow Registry
@@ -167,7 +170,7 @@ public interface FlowRegistry {
      * @throws NullPointerException if any of the arguments is not specified
      * @throws IllegalArgumentException if the given version is less than 1
      */
-    VersionedFlowSnapshot getFlowContents(String bucketId, String flowId, int version, NiFiUser user) throws IOException, NiFiRegistryException;
+    VersionedFlowSnapshot getFlowContents(String bucketId, String flowId, int version, boolean fetchRemoteFlows, NiFiUser user) throws IOException, NiFiRegistryException;
 
     /**
      * Retrieves the contents of the Flow with the given Bucket ID, Flow ID, and version, from the Flow Registry
@@ -175,6 +178,8 @@ public interface FlowRegistry {
      * @param bucketId the ID of the bucket
      * @param flowId the ID of the flow
      * @param version the version to retrieve
+     * @param fetchRemoteFlows if the remote flow has a child Process Group that also tracks to a remote flow, this specifies whether or not
+     *            the child's contents should be fetched.
      * @return the contents of the Flow from the Flow Registry
      *
      * @throws IOException if unable to communicate with the Flow Registry
@@ -183,7 +188,7 @@ public interface FlowRegistry {
      * @throws NullPointerException if any of the arguments is not specified
      * @throws IllegalArgumentException if the given version is less than 1
      */
-    VersionedFlowSnapshot getFlowContents(String bucketId, String flowId, int version) throws IOException, NiFiRegistryException;
+    VersionedFlowSnapshot getFlowContents(String bucketId, String flowId, int version, boolean fetchRemoteFlows) throws IOException, NiFiRegistryException;
 
     /**
      * Retrieves a VersionedFlow by bucket id and flow id

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java

@@ -165,8 +165,11 @@ import org.apache.nifi.provenance.StandardProvenanceEventRecord;
 import org.apache.nifi.registry.ComponentVariableRegistry;
 import org.apache.nifi.registry.VariableRegistry;
 import org.apache.nifi.registry.flow.FlowRegistryClient;
+import org.apache.nifi.registry.flow.StandardVersionControlInformation;
+import org.apache.nifi.registry.flow.VersionControlInformation;
 import org.apache.nifi.registry.flow.VersionedConnection;
 import org.apache.nifi.registry.flow.VersionedProcessGroup;
+import org.apache.nifi.registry.flow.mapping.NiFiRegistryFlowMapper;
 import org.apache.nifi.registry.variable.MutableVariableRegistry;
 import org.apache.nifi.registry.variable.StandardComponentVariableRegistry;
 import org.apache.nifi.remote.HttpRemoteSiteListener;
@@ -1775,6 +1778,10 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
      * processor
      */
     public void instantiateSnippet(final ProcessGroup group, final FlowSnippetDTO dto) throws ProcessorInstantiationException {
+        instantiateSnippet(group, dto, true);
+    }
+
+    private void instantiateSnippet(final ProcessGroup group, final FlowSnippetDTO dto, final boolean topLevel) throws ProcessorInstantiationException {
         writeLock.lock();
         try {
             validateSnippetContents(requireNonNull(group), dto);
@@ -1789,6 +1796,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 serviceNode.setAnnotationData(controllerServiceDTO.getAnnotationData());
                 serviceNode.setComments(controllerServiceDTO.getComments());
                 serviceNode.setName(controllerServiceDTO.getName());
+                if (!topLevel) {
+                    serviceNode.setVersionedComponentId(controllerServiceDTO.getVersionedComponentId());
+                }
 
                 group.addControllerService(serviceNode);
             }
@@ -1812,6 +1822,10 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 }
 
                 label.setStyle(labelDTO.getStyle());
+                if (!topLevel) {
+                    label.setVersionedComponentId(labelDTO.getVersionedComponentId());
+                }
+
                 group.addLabel(label);
             }
 
@@ -1819,6 +1833,10 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             for (final FunnelDTO funnelDTO : dto.getFunnels()) {
                 final Funnel funnel = createFunnel(funnelDTO.getId());
                 funnel.setPosition(toPosition(funnelDTO.getPosition()));
+                if (!topLevel) {
+                    funnel.setVersionedComponentId(funnelDTO.getVersionedComponentId());
+                }
+
                 group.addFunnel(funnel);
             }
 
@@ -1840,6 +1858,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                     inputPort = createLocalInputPort(portDTO.getId(), portDTO.getName());
                 }
 
+                if (!topLevel) {
+                    inputPort.setVersionedComponentId(portDTO.getVersionedComponentId());
+                }
                 inputPort.setPosition(toPosition(portDTO.getPosition()));
                 inputPort.setProcessGroup(group);
                 inputPort.setComments(portDTO.getComments());
@@ -1861,6 +1882,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                     outputPort = createLocalOutputPort(portDTO.getId(), portDTO.getName());
                 }
 
+                if (!topLevel) {
+                    outputPort.setVersionedComponentId(portDTO.getVersionedComponentId());
+                }
                 outputPort.setPosition(toPosition(portDTO.getPosition()));
                 outputPort.setProcessGroup(group);
                 outputPort.setComments(portDTO.getComments());
@@ -1876,6 +1900,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
 
                 procNode.setPosition(toPosition(processorDTO.getPosition()));
                 procNode.setProcessGroup(group);
+                if (!topLevel) {
+                    procNode.setVersionedComponentId(processorDTO.getVersionedComponentId());
+                }
 
                 final ProcessorConfigDTO config = processorDTO.getConfig();
                 procNode.setComments(config.getComments());
@@ -1936,6 +1963,10 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 remoteGroup.setPosition(toPosition(remoteGroupDTO.getPosition()));
                 remoteGroup.setCommunicationsTimeout(remoteGroupDTO.getCommunicationsTimeout());
                 remoteGroup.setYieldDuration(remoteGroupDTO.getYieldDuration());
+                if (!topLevel) {
+                    remoteGroup.setVersionedComponentId(remoteGroupDTO.getVersionedComponentId());
+                }
+
                 if (remoteGroupDTO.getTransportProtocol() == null) {
                     remoteGroup.setTransportProtocol(SiteToSiteTransportProtocol.RAW);
                 } else {
@@ -1979,6 +2010,12 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                     childGroup.setVariables(groupDTO.getVariables());
                 }
 
+                // If this Process Group is 'top level' then we do not set versioned component ID's.
+                // We do this only if this component is the child of a Versioned Component.
+                if (!topLevel) {
+                    childGroup.setVersionedComponentId(groupDTO.getVersionedComponentId());
+                }
+
                 group.addProcessGroup(childGroup);
 
                 final FlowSnippetDTO contents = groupDTO.getContents();
@@ -1995,7 +2032,18 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 childTemplateDTO.setFunnels(contents.getFunnels());
                 childTemplateDTO.setRemoteProcessGroups(contents.getRemoteProcessGroups());
                 childTemplateDTO.setControllerServices(contents.getControllerServices());
-                instantiateSnippet(childGroup, childTemplateDTO);
+                instantiateSnippet(childGroup, childTemplateDTO, false);
+
+                if (groupDTO.getVersionControlInformation() != null) {
+                    final NiFiRegistryFlowMapper flowMapper = new NiFiRegistryFlowMapper();
+                    final VersionedProcessGroup versionedGroup = flowMapper.mapProcessGroup(childGroup, getFlowRegistryClient(), false);
+
+                    final VersionControlInformation vci = StandardVersionControlInformation.Builder
+                        .fromDto(groupDTO.getVersionControlInformation())
+                        .flowSnapshot(versionedGroup)
+                        .build();
+                    childGroup.setVersionControlInformation(vci, Collections.emptyMap());
+                }
             }
 
             //
@@ -2039,6 +2087,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 }
 
                 final Connection connection = createConnection(connectionDTO.getId(), connectionDTO.getName(), source, destination, relationships);
+                if (!topLevel) {
+                    connection.setVersionedComponentId(connectionDTO.getVersionedComponentId());
+                }
 
                 if (connectionDTO.getBends() != null) {
                     final List<Position> bendPoints = new ArrayList<>();
@@ -2088,6 +2139,7 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             for (final RemoteProcessGroupPortDTO port : ports) {
                 final StandardRemoteProcessGroupPortDescriptor descriptor = new StandardRemoteProcessGroupPortDescriptor();
                 descriptor.setId(port.getId());
+                descriptor.setVersionedComponentId(port.getVersionedComponentId());
                 descriptor.setTargetId(port.getTargetId());
                 descriptor.setName(port.getName());
                 descriptor.setComments(port.getComments());

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/groups/StandardProcessGroup.java

@@ -2821,7 +2821,7 @@ public final class StandardProcessGroup implements ProcessGroup {
             versionControlInformation.getBucketIdentifier(),
             versionControlInformation.getFlowIdentifier(),
             versionControlInformation.getVersion(),
-            versionControlInformation.getFlowSnapshot(),
+            stripContentsFromRemoteDescendantGroups(versionControlInformation.getFlowSnapshot(), true),
             versionControlInformation.isModified(),
             versionControlInformation.isCurrent()) {
 
@@ -2849,6 +2849,51 @@ public final class StandardProcessGroup implements ProcessGroup {
         }
     }
 
+    private VersionedProcessGroup stripContentsFromRemoteDescendantGroups(final VersionedProcessGroup processGroup, final boolean topLevel) {
+        if (processGroup == null) {
+            return null;
+        }
+
+        final VersionedProcessGroup copy = new VersionedProcessGroup();
+        copy.setComments(processGroup.getComments());
+        copy.setComponentType(processGroup.getComponentType());
+        copy.setGroupIdentifier(processGroup.getGroupIdentifier());
+        copy.setIdentifier(processGroup.getIdentifier());
+        copy.setName(processGroup.getName());
+        copy.setPosition(processGroup.getPosition());
+        copy.setVersionedFlowCoordinates(topLevel ? null : processGroup.getVersionedFlowCoordinates());
+        copy.setConnections(processGroup.getConnections());
+        copy.setControllerServices(processGroup.getControllerServices());
+        copy.setFunnels(processGroup.getFunnels());
+        copy.setInputPorts(processGroup.getInputPorts());
+        copy.setOutputPorts(processGroup.getOutputPorts());
+        copy.setProcessors(processGroup.getProcessors());
+        copy.setRemoteProcessGroups(processGroup.getRemoteProcessGroups());
+        copy.setVariables(processGroup.getVariables());
+
+        final Set<VersionedProcessGroup> copyChildren = new HashSet<>();
+
+        for (final VersionedProcessGroup childGroup : processGroup.getProcessGroups()) {
+            if (childGroup.getVersionedFlowCoordinates() == null) {
+                copyChildren.add(stripContentsFromRemoteDescendantGroups(childGroup, false));
+            } else {
+                final VersionedProcessGroup childCopy = new VersionedProcessGroup();
+                childCopy.setComments(childGroup.getComments());
+                childCopy.setComponentType(childGroup.getComponentType());
+                childCopy.setGroupIdentifier(childGroup.getGroupIdentifier());
+                childCopy.setIdentifier(childGroup.getIdentifier());
+                childCopy.setName(childGroup.getName());
+                childCopy.setPosition(childGroup.getPosition());
+                childCopy.setVersionedFlowCoordinates(childGroup.getVersionedFlowCoordinates());
+
+                copyChildren.add(childCopy);
+            }
+        }
+
+        copy.setProcessGroups(copyChildren);
+        return copy;
+    }
+
     @Override
     public void disconnectVersionControl() {
         writeLock.lock();
@@ -2900,7 +2945,7 @@ public final class StandardProcessGroup implements ProcessGroup {
             });
 
         processGroup.getProcessGroups().stream()
-            .filter(childGroup -> childGroup.getVersionControlInformation() != null)
+            .filter(childGroup -> childGroup.getVersionControlInformation() == null)
             .forEach(childGroup -> applyVersionedComponentIds(childGroup, lookup));
     }
 
@@ -2925,7 +2970,7 @@ public final class StandardProcessGroup implements ProcessGroup {
             // We have not yet obtained the snapshot from the Flow Registry, so we need to request the snapshot of our local version of the flow from the Flow Registry.
             // This allows us to know whether or not the flow has been modified since it was last synced with the Flow Registry.
             try {
-                final VersionedFlowSnapshot registrySnapshot = flowRegistry.getFlowContents(vci.getBucketIdentifier(), vci.getFlowIdentifier(), vci.getVersion());
+                final VersionedFlowSnapshot registrySnapshot = flowRegistry.getFlowContents(vci.getBucketIdentifier(), vci.getFlowIdentifier(), vci.getVersion(), false);
                 final VersionedProcessGroup registryFlow = registrySnapshot.getFlowContents();
                 vci.setFlowSnapshot(registryFlow);
             } catch (final IOException | NiFiRegistryException e) {
@@ -2958,7 +3003,8 @@ public final class StandardProcessGroup implements ProcessGroup {
 
 
     @Override
-    public void updateFlow(final VersionedFlowSnapshot proposedSnapshot, final String componentIdSeed, final boolean verifyNotDirty, final boolean updateSettings) {
+    public void updateFlow(final VersionedFlowSnapshot proposedSnapshot, final String componentIdSeed, final boolean verifyNotDirty, final boolean updateSettings,
+            final boolean updateDescendantVersionedFlows) {
         writeLock.lock();
         try {
             verifyCanUpdate(proposedSnapshot, true, verifyNotDirty);
@@ -2986,7 +3032,7 @@ public final class StandardProcessGroup implements ProcessGroup {
             }
 
             final Set<String> knownVariables = getKnownVariableNames();
-            updateProcessGroup(this, proposedSnapshot.getFlowContents(), componentIdSeed, updatedVersionedComponentIds, false, updateSettings, knownVariables);
+            updateProcessGroup(this, proposedSnapshot.getFlowContents(), componentIdSeed, updatedVersionedComponentIds, false, updateSettings, updateDescendantVersionedFlows, knownVariables);
         } catch (final ProcessorInstantiationException pie) {
             throw new RuntimeException(pie);
         } finally {
@@ -3013,7 +3059,8 @@ public final class StandardProcessGroup implements ProcessGroup {
 
 
     private void updateProcessGroup(final ProcessGroup group, final VersionedProcessGroup proposed, final String componentIdSeed,
-        final Set<String> updatedVersionedComponentIds, final boolean updatePosition, final boolean updateName, final Set<String> variablesToSkip) throws ProcessorInstantiationException {
+        final Set<String> updatedVersionedComponentIds, final boolean updatePosition, final boolean updateName, final boolean updateDescendantVersionedGroups,
+        final Set<String> variablesToSkip) throws ProcessorInstantiationException {
 
         group.setComments(proposed.getComments());
 
@@ -3033,14 +3080,8 @@ public final class StandardProcessGroup implements ProcessGroup {
             .map(VariableDescriptor::getName)
             .collect(Collectors.toSet());
 
-        final Set<String> variablesRemoved = new HashSet<>(existingVariableNames);
-
-        if (proposed.getVariables() != null) {
-            variablesRemoved.removeAll(proposed.getVariables().keySet());
-        }
 
         final Map<String, String> updatedVariableMap = new HashMap<>();
-        variablesRemoved.forEach(var -> updatedVariableMap.put(var, null));
 
         // If any new variables exist in the proposed flow, add those to the variable registry.
         for (final Map.Entry<String, String> entry : proposed.getVariables().entrySet()) {
@@ -3069,6 +3110,7 @@ public final class StandardProcessGroup implements ProcessGroup {
                 .flowId(flowId)
                 .flowName(flowId) // flow id not yet known
                 .version(version)
+                .flowSnapshot(proposed)
                 .modified(false)
                 .current(true)
                 .build();
@@ -3084,11 +3126,13 @@ public final class StandardProcessGroup implements ProcessGroup {
         for (final VersionedProcessGroup proposedChildGroup : proposed.getProcessGroups()) {
             final ProcessGroup childGroup = childGroupsByVersionedId.get(proposedChildGroup.getIdentifier());
 
+            final VersionedFlowCoordinates childCoordinates = proposedChildGroup.getVersionedFlowCoordinates();
+
             if (childGroup == null) {
                 final ProcessGroup added = addProcessGroup(group, proposedChildGroup, componentIdSeed, variablesToSkip);
                 LOG.info("Added {} to {}", added, this);
-            } else {
+            } else if (childCoordinates == null || updateDescendantVersionedGroups) {
-                updateProcessGroup(childGroup, proposedChildGroup, componentIdSeed, updatedVersionedComponentIds, true, updateName, variablesToSkip);
+                updateProcessGroup(childGroup, proposedChildGroup, componentIdSeed, updatedVersionedComponentIds, true, updateName, updateDescendantVersionedGroups, variablesToSkip);
                 LOG.info("Updated {}", childGroup);
             }
 
@@ -3367,7 +3411,7 @@ public final class StandardProcessGroup implements ProcessGroup {
         final ProcessGroup group = flowController.createProcessGroup(generateUuid(componentIdSeed));
         group.setVersionedComponentId(proposed.getIdentifier());
         group.setParent(destination);
-        updateProcessGroup(group, proposed, componentIdSeed, Collections.emptySet(), true, true, variablesToSkip);
+        updateProcessGroup(group, proposed, componentIdSeed, Collections.emptySet(), true, true, true, variablesToSkip);
         destination.addProcessGroup(group);
         return group;
     }
@@ -3739,7 +3783,7 @@ public final class StandardProcessGroup implements ProcessGroup {
         }
 
         final NiFiRegistryFlowMapper mapper = new NiFiRegistryFlowMapper();
-        final VersionedProcessGroup versionedGroup = mapper.mapProcessGroup(this, flowController.getFlowRegistryClient(), true);
+        final VersionedProcessGroup versionedGroup = mapper.mapProcessGroup(this, flowController.getFlowRegistryClient(), false);
 
         final ComparableDataFlow currentFlow = new ComparableDataFlow() {
             @Override
@@ -3765,7 +3809,7 @@ public final class StandardProcessGroup implements ProcessGroup {
             }
         };
 
-        final FlowComparator flowComparator = new StandardFlowComparator(currentFlow, snapshotFlow, new EvolvingDifferenceDescriptor());
+        final FlowComparator flowComparator = new StandardFlowComparator(snapshotFlow, currentFlow, new EvolvingDifferenceDescriptor());
         final FlowComparison comparison = flowComparator.compare();
         final Set<FlowDifference> differences = comparison.getDifferences();
         final Set<FlowDifference> functionalDifferences = differences.stream()
@@ -4002,4 +4046,69 @@ public final class StandardProcessGroup implements ProcessGroup {
             findAllProcessGroups(child, map);
         }
     }
+
+    @Override
+    public void verifyCanSaveToFlowRegistry(final String registryId, final String bucketId, final String flowId) {
+        verifyNoDescendantsWithLocalModifications("be saved to a Flow Registry");
+
+        final StandardVersionControlInformation vci = versionControlInfo.get();
+        if (vci != null) {
+            if (flowId != null && flowId.equals(vci.getFlowIdentifier())) {
+                // Flow ID is the same. We want to publish the Process Group as the next version of the Flow.
+                // In order to do this, we have to ensure that the Process Group is 'current'.
+                final boolean current = vci.isCurrent();
+                if (!current) {
+                    throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + getIdentifier()
+                        + " because the Process Group in the flow is not synchronized with the most recent version of the Flow in the Flow Registry. "
+                        + "In order to publish a new version of the Flow, the Process Group must first be in synch with the latest version in the Flow Registry.");
+                }
+
+                // Flow ID matches. We want to publish the Process Group as the next version of the Flow, so we must
+                // ensure that all other parameters match as well.
+                if (!bucketId.equals(vci.getBucketIdentifier())) {
+                    throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + getIdentifier()
+                        + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
+                }
+
+                if (!registryId.equals(vci.getRegistryIdentifier())) {
+                    throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + getIdentifier()
+                        + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
+                }
+            } else if (flowId != null) {
+                // Flow ID is specified but different. This is not allowed, because Flow ID's are automatically generated,
+                // and if the client is specifying an ID then it is either trying to assign the ID of the Flow or it is
+                // attempting to save a new version of a different flow. Saving a new version of a different Flow is
+                // not allowed because the Process Group must be in synch with the latest version of the flow before that
+                // can be done.
+                throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + getIdentifier()
+                    + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
+            }
+        }
+    }
+
+    @Override
+    public void verifyCanRevertLocalModifications() {
+        final StandardVersionControlInformation svci = versionControlInfo.get();
+        if (svci == null) {
+            throw new IllegalStateException("Cannot revert local modifications to Process Group because the Process Group is not under Version Control.");
+        }
+
+        verifyNoDescendantsWithLocalModifications("have its local modifications reverted");
+    }
+
+    @Override
+    public void verifyCanShowLocalModifications() {
+
+    }
+
+    private void verifyNoDescendantsWithLocalModifications(final String action) {
+        for (final ProcessGroup descendant : findAllProcessGroups()) {
+            final VersionControlInformation descendantVci = descendant.getVersionControlInformation();
+            if (descendantVci != null && descendantVci.isModified()) {
+                throw new IllegalStateException("Process Group cannot " + action + " because it contains a child or descendant Process Group that is under Version Control and "
+                    + "has local modifications. Each descendant Process Group that is under Version Control must first be reverted or have its changes pushed to the Flow Registry before "
+                    + "this action can be performed on the parent Process Group.");
+            }
+        }
+    }
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/registry/flow/RestBasedFlowRegistry.java

@@ -178,21 +178,24 @@ public class RestBasedFlowRegistry implements FlowRegistry {
     }
 
     @Override
-    public VersionedFlowSnapshot getFlowContents(final String bucketId, final String flowId, final int version, final NiFiUser user) throws IOException, NiFiRegistryException {
+    public VersionedFlowSnapshot getFlowContents(final String bucketId, final String flowId, final int version, final boolean fetchRemoteFlows, final NiFiUser user)
+            throws IOException, NiFiRegistryException {
         final FlowSnapshotClient snapshotClient = getRegistryClient().getFlowSnapshotClient(getIdentity(user));
         final VersionedFlowSnapshot flowSnapshot = snapshotClient.get(bucketId, flowId, version);
 
-        final VersionedProcessGroup contents = flowSnapshot.getFlowContents();
+        if (fetchRemoteFlows) {
-        for (final VersionedProcessGroup child : contents.getProcessGroups()) {
+            final VersionedProcessGroup contents = flowSnapshot.getFlowContents();
-            populateVersionedContentsRecursively(child, user);
+            for (final VersionedProcessGroup child : contents.getProcessGroups()) {
+                populateVersionedContentsRecursively(child, user);
+            }
         }
 
         return flowSnapshot;
     }
 
     @Override
-    public VersionedFlowSnapshot getFlowContents(final String bucketId, final String flowId, final int version) throws IOException, NiFiRegistryException {
+    public VersionedFlowSnapshot getFlowContents(final String bucketId, final String flowId, final int version, final boolean fetchRemoteFlows) throws IOException, NiFiRegistryException {
-        return getFlowContents(bucketId, flowId, version, null);
+        return getFlowContents(bucketId, flowId, version, fetchRemoteFlows, null);
     }
 
     private void populateVersionedContentsRecursively(final VersionedProcessGroup group, final NiFiUser user) throws NiFiRegistryException, IOException {
@@ -214,7 +217,7 @@ public class RestBasedFlowRegistry implements FlowRegistry {
             }
 
             final FlowRegistry flowRegistry = flowRegistryClient.getFlowRegistry(registryId);
-            final VersionedFlowSnapshot snapshot = flowRegistry.getFlowContents(bucketId, flowId, version, user);
+            final VersionedFlowSnapshot snapshot = flowRegistry.getFlowContents(bucketId, flowId, version, true, user);
             final VersionedProcessGroup contents = snapshot.getFlowContents();
 
             group.setComments(contents.getComments());

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/test/java/org/apache/nifi/controller/service/mock/MockProcessGroup.java

@@ -649,12 +649,16 @@ public class MockProcessGroup implements ProcessGroup {
     public void verifyCanUpdate(VersionedFlowSnapshot updatedFlow, boolean verifyConnectionRemoval, boolean verifyNotDirty) {
     }
 
+    @Override
+    public void verifyCanSaveToFlowRegistry(String registryId, String bucketId, String flowId) {
+    }
+
     @Override
     public void synchronizeWithFlowRegistry(FlowRegistryClient flowRegistry) {
     }
 
     @Override
-    public void updateFlow(VersionedFlowSnapshot proposedFlow, String componentIdSeed, boolean verifyNotDirty, boolean updateSettings) {
+    public void updateFlow(VersionedFlowSnapshot proposedFlow, String componentIdSeed, boolean verifyNotDirty, boolean updateSettings, boolean updateDescendantVerisonedFlows) {
     }
 
     @Override
@@ -666,4 +670,12 @@ public class MockProcessGroup implements ProcessGroup {
     public void disconnectVersionControl() {
         this.versionControlInfo = null;
     }
+
+    @Override
+    public void verifyCanRevertLocalModifications() {
+    }
+
+    @Override
+    public void verifyCanShowLocalModifications() {
+    }
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/NiFiServiceFacade.java

@@ -1368,11 +1368,13 @@ public interface NiFiServiceFacade {
      * Retrieves the Versioned Flow Snapshot for the coordinates provided by the given Version Control Information DTO
      *
      * @param versionControlInfo the coordinates of the versioned flow
+     * @param fetchRemoteFlows if the contents of Versioned Flow that is fetched contains a child/descendant Process Group
+     *            that is also under Version Control, this indicates whether that remote flow should also be fetched
      * @return the VersionedFlowSnapshot that corresponds to the given coordinates
      *
      * @throws ResourceNotFoundException if the Versioned Flow Snapshot could not be found
      */
-    VersionedFlowSnapshot getVersionedFlowSnapshot(VersionControlInformationDTO versionControlInfo) throws IOException;
+    VersionedFlowSnapshot getVersionedFlowSnapshot(VersionControlInformationDTO versionControlInfo, boolean fetchRemoteFlows) throws IOException;
 
     /**
      * Returns the name of the Flow Registry that is registered with the given ID. If no Flow Registry exists with the given ID, will return
@@ -1406,6 +1408,28 @@ public interface NiFiServiceFacade {
      */
     void verifyCanUpdate(String groupId, VersionedFlowSnapshot proposedFlow, boolean verifyConnectionRemoval, boolean verifyNotDirty);
 
+    /**
+     * Verifies that the Process Group with the given identifier can be saved to the flow registry
+     *
+     * @param groupId the ID of the Process Group
+     * @param registryId the ID of the Flow Registry
+     * @param bucketId the ID of the bucket
+     * @param flowId the ID of the flow
+     *
+     * @throws IllegalStateException if the Process Group cannot be saved to the flow registry with the coordinates specified
+     */
+    void verifyCanSaveToFlowRegistry(String groupId, String registryId, String bucketId, String flowId);
+
+    /**
+     * Verifies that the Process Group with the given identifier can have its local modifications reverted to the given VersionedFlowSnapshot
+     *
+     * @param groupId the ID of the Process Group
+     * @param versionedFlowSnapshot the Versioned Flow Snapshot
+     *
+     * @throws IllegalStateException if the Process Group cannot have its local modifications reverted
+     */
+    void verifyCanRevertLocalModifications(String groupId, VersionedFlowSnapshot versionedFlowSnapshot);
+
     /**
      * Updates the Process group with the given ID to match the new snapshot
      *
@@ -1414,10 +1438,12 @@ public interface NiFiServiceFacade {
      * @param versionControlInfo the Version Control information
      * @param snapshot the new snapshot
      * @param componentIdSeed the seed to use for generating new component ID's
+     * @param updateDescendantVersionedFlows if a child/descendant Process Group is under Version Control, specifies whether or not to
+     *            update the contents of that Process Group
      * @return the Process Group
      */
     ProcessGroupEntity updateProcessGroup(Revision revision, String groupId, VersionControlInformationDTO versionControlInfo, VersionedFlowSnapshot snapshot, String componentIdSeed,
-        boolean verifyNotModified);
+        boolean verifyNotModified, boolean updateDescendantVersionedFlows);
 
     /**
      * Updates the Process group with the given ID to match the new snapshot
@@ -1429,10 +1455,12 @@ public interface NiFiServiceFacade {
      * @param snapshot the new snapshot
      * @param componentIdSeed the seed to use for generating new component ID's
      * @param updateSettings whether or not the process group's name and position should be updated
+     * @param updateDescendantVersionedFlows if a child/descendant Process Group is under Version Control, specifies whether or not to
+     *            update the contents of that Process Group
      * @return the Process Group
      */
     ProcessGroupEntity updateProcessGroupContents(NiFiUser user, Revision revision, String groupId, VersionControlInformationDTO versionControlInfo, VersionedFlowSnapshot snapshot, String componentIdSeed,
-        boolean verifyNotModified, boolean updateSettings);
+        boolean verifyNotModified, boolean updateSettings, boolean updateDescendantVersionedFlows);
 
     // ----------------------------------------
     // Component state methods

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/StandardNiFiServiceFacade.java

@@ -97,13 +97,12 @@ import org.apache.nifi.registry.flow.VersionControlInformation;
 import org.apache.nifi.registry.flow.VersionedComponent;
 import org.apache.nifi.registry.flow.VersionedConnection;
 import org.apache.nifi.registry.flow.VersionedFlow;
-import org.apache.nifi.registry.flow.VersionedFlowCoordinates;
 import org.apache.nifi.registry.flow.VersionedFlowSnapshot;
 import org.apache.nifi.registry.flow.VersionedFlowSnapshotMetadata;
 import org.apache.nifi.registry.flow.VersionedProcessGroup;
 import org.apache.nifi.registry.flow.diff.ComparableDataFlow;
+import org.apache.nifi.registry.flow.diff.ConciseEvolvingDifferenceDescriptor;
 import org.apache.nifi.registry.flow.diff.DifferenceType;
-import org.apache.nifi.registry.flow.diff.EvolvingDifferenceDescriptor;
 import org.apache.nifi.registry.flow.diff.FlowComparator;
 import org.apache.nifi.registry.flow.diff.FlowComparison;
 import org.apache.nifi.registry.flow.diff.FlowDifference;
@@ -3751,10 +3750,10 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
         }
 
         final VersionedFlowSnapshot versionedFlowSnapshot = flowRegistry.getFlowContents(versionControlInfo.getBucketIdentifier(),
-            versionControlInfo.getFlowIdentifier(), versionControlInfo.getVersion(), NiFiUserUtils.getNiFiUser());
+            versionControlInfo.getFlowIdentifier(), versionControlInfo.getVersion(), false, NiFiUserUtils.getNiFiUser());
 
         final NiFiRegistryFlowMapper mapper = new NiFiRegistryFlowMapper();
-        final VersionedProcessGroup localGroup = mapper.mapProcessGroup(processGroup, flowRegistryClient, true);
+        final VersionedProcessGroup localGroup = mapper.mapProcessGroup(processGroup, flowRegistryClient, false);
         final VersionedProcessGroup registryGroup = versionedFlowSnapshot.getFlowContents();
 
         final ComparableDataFlow localFlow = new ComparableDataFlow() {
@@ -3781,7 +3780,7 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
             }
         };
 
-        final FlowComparator flowComparator = new StandardFlowComparator(registryFlow, localFlow, new EvolvingDifferenceDescriptor());
+        final FlowComparator flowComparator = new StandardFlowComparator(registryFlow, localFlow, new ConciseEvolvingDifferenceDescriptor());
         final FlowComparison flowComparison = flowComparator.compare();
 
         final Set<ComponentDifferenceDTO> differenceDtos = dtoFactory.createComponentDifferenceDtos(flowComparison);
@@ -3852,6 +3851,23 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
         group.verifyCanUpdate(proposedFlow, verifyConnectionRemoval, verifyNotDirty);
     }
 
+    @Override
+    public void verifyCanSaveToFlowRegistry(final String groupId, final String registryId, final String bucketId, final String flowId) {
+        final ProcessGroup group = processGroupDAO.getProcessGroup(groupId);
+        group.verifyCanSaveToFlowRegistry(registryId, bucketId, flowId);
+    }
+
+    @Override
+    public void verifyCanRevertLocalModifications(final String groupId, final VersionedFlowSnapshot versionedFlowSnapshot) {
+        final ProcessGroup group = processGroupDAO.getProcessGroup(groupId);
+        group.verifyCanRevertLocalModifications();
+
+        // verify that the process group can be updated to the given snapshot. We do not verify that connections can
+        // be removed, because the flow may still be running, and it only matters that the connections can be removed once the components
+        // have been stopped.
+        group.verifyCanUpdate(versionedFlowSnapshot, false, false);
+    }
+
     @Override
     public Set<AffectedComponentEntity> getComponentsAffectedByVersionChange(final String processGroupId, final VersionedFlowSnapshot updatedSnapshot, final NiFiUser user) throws IOException {
         final ProcessGroup group = processGroupDAO.getProcessGroup(processGroupId);
@@ -4028,7 +4044,7 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
     }
 
     @Override
-    public VersionedFlowSnapshot getVersionedFlowSnapshot(final VersionControlInformationDTO versionControlInfo) throws IOException {
+    public VersionedFlowSnapshot getVersionedFlowSnapshot(final VersionControlInformationDTO versionControlInfo, final boolean fetchRemoteFlows) throws IOException {
         final FlowRegistry flowRegistry = flowRegistryClient.getFlowRegistry(versionControlInfo.getRegistryId());
         if (flowRegistry == null) {
             throw new ResourceNotFoundException("Could not find any Flow Registry registered with identifier " + versionControlInfo.getRegistryId());
@@ -4036,15 +4052,12 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
 
         final VersionedFlowSnapshot snapshot;
         try {
-            snapshot = flowRegistry.getFlowContents(versionControlInfo.getBucketId(), versionControlInfo.getFlowId(), versionControlInfo.getVersion(), NiFiUserUtils.getNiFiUser());
+            snapshot = flowRegistry.getFlowContents(versionControlInfo.getBucketId(), versionControlInfo.getFlowId(), versionControlInfo.getVersion(), fetchRemoteFlows, NiFiUserUtils.getNiFiUser());
         } catch (final NiFiRegistryException e) {
             throw new IllegalArgumentException("The Flow Registry with ID " + versionControlInfo.getRegistryId() + " reports that no Flow exists with Bucket "
                 + versionControlInfo.getBucketId() + ", Flow " + versionControlInfo.getFlowId() + ", Version " + versionControlInfo.getVersion());
         }
 
-        // If this Flow has a reference to a remote flow, we need to pull that remote flow as well
-        populateVersionedChildFlows(snapshot);
-
         return snapshot;
     }
 
@@ -4054,74 +4067,22 @@ public class StandardNiFiServiceFacade implements NiFiServiceFacade {
         return flowRegistry == null ? flowRegistryId : flowRegistry.getName();
     }
 
-    private void populateVersionedChildFlows(final VersionedFlowSnapshot snapshot) throws IOException {
-        final VersionedProcessGroup group = snapshot.getFlowContents();
-
-        for (final VersionedProcessGroup child : group.getProcessGroups()) {
-            populateVersionedFlows(child);
-        }
-    }
-
-    private void populateVersionedFlows(final VersionedProcessGroup group) throws IOException {
-        final VersionedFlowCoordinates remoteCoordinates = group.getVersionedFlowCoordinates();
-
-        if (remoteCoordinates != null) {
-            final String registryUrl = remoteCoordinates.getRegistryUrl();
-            final String registryId = flowRegistryClient.getFlowRegistryId(registryUrl);
-            if (registryId == null) {
-                throw new IllegalArgumentException("Process Group with ID " + group.getIdentifier() + " is under Version Control, referencing a Flow Registry at URL [" + registryUrl
-                    + "], but no Flow Registry is currently registered for that URL.");
-            }
-
-            final FlowRegistry flowRegistry = flowRegistryClient.getFlowRegistry(registryId);
-
-            final VersionedFlowSnapshot childSnapshot;
-            try {
-                childSnapshot = flowRegistry.getFlowContents(remoteCoordinates.getBucketId(), remoteCoordinates.getFlowId(), remoteCoordinates.getVersion(), NiFiUserUtils.getNiFiUser());
-            } catch (final NiFiRegistryException e) {
-                throw new IllegalArgumentException("The Flow Registry with ID " + registryId + " reports that no Flow exists with Bucket "
-                    + remoteCoordinates.getBucketId() + ", Flow " + remoteCoordinates.getFlowId() + ", Version " + remoteCoordinates.getVersion());
-            }
-
-            final VersionedProcessGroup fetchedGroup = childSnapshot.getFlowContents();
-            group.setComments(fetchedGroup.getComments());
-            group.setPosition(fetchedGroup.getPosition());
-            group.setName(fetchedGroup.getName());
-            group.setVariables(fetchedGroup.getVariables());
-
-            group.setConnections(new LinkedHashSet<>(fetchedGroup.getConnections()));
-            group.setControllerServices(new LinkedHashSet<>(fetchedGroup.getControllerServices()));
-            group.setFunnels(new LinkedHashSet<>(fetchedGroup.getFunnels()));
-            group.setInputPorts(new LinkedHashSet<>(fetchedGroup.getInputPorts()));
-            group.setLabels(new LinkedHashSet<>(fetchedGroup.getLabels()));
-            group.setOutputPorts(new LinkedHashSet<>(fetchedGroup.getOutputPorts()));
-            group.setProcessGroups(new LinkedHashSet<>(fetchedGroup.getProcessGroups()));
-            group.setProcessors(new LinkedHashSet<>(fetchedGroup.getProcessors()));
-            group.setRemoteProcessGroups(new LinkedHashSet<>(fetchedGroup.getRemoteProcessGroups()));
-        }
-
-        for (final VersionedProcessGroup child : group.getProcessGroups()) {
-            populateVersionedFlows(child);
-        }
-    }
-
-
     @Override
     public ProcessGroupEntity updateProcessGroup(final Revision revision, final String groupId, final VersionControlInformationDTO versionControlInfo,
-        final VersionedFlowSnapshot proposedFlowSnapshot, final String componentIdSeed, final boolean verifyNotModified) {
+        final VersionedFlowSnapshot proposedFlowSnapshot, final String componentIdSeed, final boolean verifyNotModified, final boolean updateDescendantVersionedFlows) {
 
         final NiFiUser user = NiFiUserUtils.getNiFiUser();
-        return updateProcessGroupContents(user, revision, groupId, versionControlInfo, proposedFlowSnapshot, componentIdSeed, verifyNotModified, true);
+        return updateProcessGroupContents(user, revision, groupId, versionControlInfo, proposedFlowSnapshot, componentIdSeed, verifyNotModified, true, updateDescendantVersionedFlows);
     }
 
     @Override
     public ProcessGroupEntity updateProcessGroupContents(final NiFiUser user, final Revision revision, final String groupId, final VersionControlInformationDTO versionControlInfo,
-        final VersionedFlowSnapshot proposedFlowSnapshot, final String componentIdSeed, final boolean verifyNotModified, final boolean updateSettings) {
+        final VersionedFlowSnapshot proposedFlowSnapshot, final String componentIdSeed, final boolean verifyNotModified, final boolean updateSettings, final boolean updateDescendantVersionedFlows) {
 
         final ProcessGroup processGroupNode = processGroupDAO.getProcessGroup(groupId);
         final RevisionUpdate<ProcessGroupDTO> snapshot = updateComponent(user, revision,
             processGroupNode,
-            () -> processGroupDAO.updateProcessGroupFlow(groupId, proposedFlowSnapshot, versionControlInfo, componentIdSeed, verifyNotModified, updateSettings),
+            () -> processGroupDAO.updateProcessGroupFlow(groupId, proposedFlowSnapshot, versionControlInfo, componentIdSeed, verifyNotModified, updateSettings, updateDescendantVersionedFlows),
             processGroup -> dtoFactory.createProcessGroupDto(processGroup));
 
         final PermissionsDTO permissions = dtoFactory.createPermissionsDto(processGroupNode);

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/api/ProcessGroupResource.java

@@ -1644,7 +1644,7 @@ public class ProcessGroupResource extends ApplicationResource {
         if (versionControlInfo != null) {
             // Step 1: Ensure that user has write permissions to the Process Group. If not, then immediately fail.
             // Step 2: Retrieve flow from Flow Registry
-            final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(versionControlInfo);
+            final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(versionControlInfo, true);
             final Bucket bucket = flowSnapshot.getBucket();
             final VersionedFlow flow = flowSnapshot.getFlow();
 
@@ -1653,6 +1653,8 @@ public class ProcessGroupResource extends ApplicationResource {
             versionControlInfo.setFlowDescription(flow.getDescription());
 
             versionControlInfo.setRegistryName(serviceFacade.getFlowRegistryName(versionControlInfo.getRegistryId()));
+            versionControlInfo.setModified(false);
+            versionControlInfo.setCurrent(flowSnapshot.isLatest());
 
             // Step 3: Resolve Bundle info
             BundleUtils.discoverCompatibleBundles(flowSnapshot.getFlowContents());
@@ -1709,8 +1711,13 @@ public class ProcessGroupResource extends ApplicationResource {
                         final RevisionDTO revisionDto = entity.getRevision();
                         final String newGroupId = entity.getComponent().getId();
                         final Revision newGroupRevision = new Revision(revisionDto.getVersion(), revisionDto.getClientId(), newGroupId);
+
+                        // We don't want the Process Group's position to be updated because we want to keep the position where the user
+                        // placed the Process Group. However, we do want to use the name of the Process Group that is in the Flow Contents.
+                        // To accomplish this, we call updateProcessGroupContents() passing 'true' for the updateSettings flag but null out the position.
+                        flowSnapshot.getFlowContents().setPosition(null);
                         entity = serviceFacade.updateProcessGroupContents(NiFiUserUtils.getNiFiUser(), newGroupRevision, newGroupId,
-                            versionControlInfo, flowSnapshot, getIdGenerationSeed().orElse(null), false, false);
+                        versionControlInfo, flowSnapshot, getIdGenerationSeed().orElse(null), false, true, true);
                     }
 
                     populateRemainingProcessGroupEntityContent(entity);

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/api/VersionsResource.java

@@ -17,21 +17,6 @@
 
 package org.apache.nifi.web.api;
 
-import java.io.IOException;
-import java.net.URI;
-import java.net.URISyntaxException;
-import java.util.Collections;
-import java.util.Date;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedHashSet;
-import java.util.Map;
-import java.util.Set;
-import java.util.UUID;
-import java.util.concurrent.TimeUnit;
-import java.util.function.Consumer;
-import java.util.stream.Collectors;
-
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
 import javax.ws.rs.DefaultValue;
@@ -92,10 +77,24 @@ import org.apache.nifi.web.util.AffectedComponentUtils;
 import org.apache.nifi.web.util.CancellableTimedPause;
 import org.apache.nifi.web.util.ComponentLifecycle;
 import org.apache.nifi.web.util.LifecycleManagementException;
-import org.apache.nifi.web.util.Pause;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+
 import io.swagger.annotations.Api;
 import io.swagger.annotations.ApiOperation;
 import io.swagger.annotations.ApiParam;
@@ -454,51 +453,15 @@ public class VersionsResource extends ApplicationResource {
                 super.authorizeProcessGroup(groupAuthorizable, authorizer, lookup, RequestAction.READ, true, false, true, true);
             },
             () -> {
-                final VersionControlInformationEntity entity = serviceFacade.getVersionControlInformation(groupId);
+                final VersionedFlowDTO versionedFlow = requestEntity.getVersionedFlow();
-                if (entity != null) {
+                final String registryId = versionedFlow.getRegistryId();
-                    final String flowId = requestEntity.getVersionedFlow().getFlowId();
+                final String bucketId = versionedFlow.getBucketId();
-                    if (flowId != null && flowId.equals(entity.getVersionControlInformation().getFlowId())) {
+                final String flowId = versionedFlow.getFlowId();
-                        // Flow ID is the same. We want to publish the Process Group as the next version of the Flow.
+                serviceFacade.verifyCanSaveToFlowRegistry(groupId, registryId, bucketId, flowId);
-                        // In order to do this, we have to ensure that the Process Group is 'current'.
-                        final Boolean current = entity.getVersionControlInformation().getCurrent();
-                        if (current == null) {
-                            throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + groupId
-                                + " because it is not yet known whether or not this Process Group is the most recent version of the flow. "
-                                + "Please try the request again after the Process Group has been synchronized with the Flow Registry.");
-                        }
-
-                        if (current == Boolean.FALSE) {
-                            throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + groupId
-                                + " because the Process Group in the flow is not synchronized with the most recent version of the Flow in the Flow Registry. "
-                                + "In order to publish a new version of the Flow, the Process Group must first be in synch with the latest version in the Flow Registry.");
-                        }
-
-                        // Flow ID matches. We want to publish the Process Group as the next version of the Flow, so we must
-                        // ensure that all other parameters match as well.
-                        if (!requestEntity.getVersionedFlow().getBucketId().equals(entity.getVersionControlInformation().getBucketId())) {
-                            throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + groupId
-                                + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
-                        }
-
-                        if (!requestEntity.getVersionedFlow().getRegistryId().equals(entity.getVersionControlInformation().getRegistryId())) {
-                            throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + groupId
-                                + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
-                        }
-
-                    } else if (flowId != null) {
-                        // Flow ID is specified but different. This is not allowed, because Flow ID's are automatically generated,
-                        // and if the client is specifying an ID then it is either trying to assign the ID of the Flow or it is
-                        // attempting to save a new version of a different flow. Saving a new version of a different Flow is
-                        // not allowed because the Process Group must be in synch with the latest version of the flow before that
-                        // can be done.
-                        throw new IllegalStateException("Cannot update Version Control Information for Process Group with ID " + groupId
-                            + " because the Process Group is currently synchronized with a different Versioned Flow than the one specified in the request.");
-                    }
-                }
             },
             (rev, flowEntity) -> {
                 // Register the current flow with the Flow Registry.
-                final VersionControlComponentMappingEntity mappingEntity = serviceFacade.registerFlowWithFlowRegistry(groupId, requestEntity);
+                final VersionControlComponentMappingEntity mappingEntity = serviceFacade.registerFlowWithFlowRegistry(groupId, flowEntity);
 
                 // Update the Process Group's Version Control Information
                 final VersionControlInformationEntity responseEntity = serviceFacade.setVersionControlInformation(rev, groupId,
@@ -756,7 +719,8 @@ public class VersionsResource extends ApplicationResource {
                 versionControlInfoDto.setRegistryId(requestEntity.getRegistryId());
                 versionControlInfoDto.setRegistryName(serviceFacade.getFlowRegistryName(requestEntity.getRegistryId()));
 
-                final ProcessGroupEntity updatedGroup = serviceFacade.updateProcessGroup(rev, groupId, versionControlInfoDto, flowSnapshot, getIdGenerationSeed().orElse(null), false);
+                final ProcessGroupEntity updatedGroup = serviceFacade.updateProcessGroup(rev, groupId, versionControlInfoDto, flowSnapshot, getIdGenerationSeed().orElse(null), false,
+                    entity.getUpdateDescendantVersionedFlows());
                 final VersionControlInformationDTO updatedVci = updatedGroup.getComponent().getVersionControlInformation();
 
                 final VersionControlInformationEntity responseEntity = new VersionControlInformationEntity();
@@ -1039,7 +1003,7 @@ public class VersionsResource extends ApplicationResource {
         // 14. Re-Start all Processors, Funnels, Ports that are affected and not removed.
 
         // Step 0: Get the Versioned Flow Snapshot from the Flow Registry
-        final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(requestEntity.getVersionControlInformation());
+        final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(requestEntity.getVersionControlInformation(), true);
 
         // The flow in the registry may not contain the same versions of components that we have in our flow. As a result, we need to update
         // the flow snapshot to contain compatible bundles.
@@ -1085,7 +1049,7 @@ public class VersionsResource extends ApplicationResource {
                 final Consumer<AsynchronousWebRequest<VersionControlInformationEntity>> updateTask = vcur -> {
                     try {
                         final VersionControlInformationEntity updatedVersionControlEntity = updateFlowVersion(groupId, componentLifecycle, exampleUri,
-                            affectedComponents, user, replicateRequest, requestEntity, flowSnapshot, request, idGenerationSeed, true);
+                            affectedComponents, user, replicateRequest, requestEntity, flowSnapshot, request, idGenerationSeed, true, true);
 
                         vcur.markComplete(updatedVersionControlEntity);
                     } catch (final LifecycleManagementException e) {
@@ -1188,7 +1152,7 @@ public class VersionsResource extends ApplicationResource {
         final String idGenerationSeed = getIdGenerationSeed().orElse(null);
 
         // Step 0: Get the Versioned Flow Snapshot from the Flow Registry
-        final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(requestEntity.getVersionControlInformation());
+        final VersionedFlowSnapshot flowSnapshot = serviceFacade.getVersionedFlowSnapshot(requestEntity.getVersionControlInformation(), false);
 
         // The flow in the registry may not contain the same versions of components that we have in our flow. As a result, we need to update
         // the flow snapshot to contain compatible bundles.
@@ -1221,8 +1185,7 @@ public class VersionsResource extends ApplicationResource {
             () -> {
                 // Step 3: Verify that all components in the snapshot exist on all nodes
                 // Step 4: Verify that Process Group is already under version control. If not, must start Version Control instead of updating flow
-                // Step 5: Verify that Process Group is not 'dirty'
+                serviceFacade.verifyCanRevertLocalModifications(groupId, flowSnapshot);
-                serviceFacade.verifyCanUpdate(groupId, flowSnapshot, false, false);
             },
             (revision, processGroupEntity) -> {
                 // Ensure that the information passed in is correct
@@ -1254,7 +1217,7 @@ public class VersionsResource extends ApplicationResource {
                 final Consumer<AsynchronousWebRequest<VersionControlInformationEntity>> updateTask = vcur -> {
                     try {
                         final VersionControlInformationEntity updatedVersionControlEntity = updateFlowVersion(groupId, componentLifecycle, exampleUri,
-                            affectedComponents, user, replicateRequest, requestEntity, flowSnapshot, request, idGenerationSeed, false);
+                            affectedComponents, user, replicateRequest, requestEntity, flowSnapshot, request, idGenerationSeed, false, false);
 
                         vcur.markComplete(updatedVersionControlEntity);
                     } catch (final LifecycleManagementException e) {
@@ -1288,7 +1251,7 @@ public class VersionsResource extends ApplicationResource {
     private VersionControlInformationEntity updateFlowVersion(final String groupId, final ComponentLifecycle componentLifecycle, final URI exampleUri,
         final Set<AffectedComponentEntity> affectedComponents, final NiFiUser user, final boolean replicateRequest, final VersionControlInformationEntity requestEntity,
         final VersionedFlowSnapshot flowSnapshot, final AsynchronousWebRequest<VersionControlInformationEntity> asyncRequest, final String idGenerationSeed,
-        final boolean verifyNotModified) throws LifecycleManagementException {
+        final boolean verifyNotModified, final boolean updateDescendantVersionedFlows) throws LifecycleManagementException {
 
         // Steps 6-7: Determine which components must be stopped and stop them.
         final Set<String> stoppableReferenceTypes = new HashSet<>();
@@ -1302,7 +1265,8 @@ public class VersionsResource extends ApplicationResource {
             .collect(Collectors.toSet());
 
         logger.info("Stopping {} Processors", runningComponents.size());
-        final Pause stopComponentsPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+        final CancellableTimedPause stopComponentsPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+        asyncRequest.setCancelCallback(stopComponentsPause::cancel);
         componentLifecycle.scheduleComponents(exampleUri, user, groupId, runningComponents, ScheduledState.STOPPED, stopComponentsPause);
 
         if (asyncRequest.isCancelled()) {
@@ -1317,7 +1281,8 @@ public class VersionsResource extends ApplicationResource {
             .collect(Collectors.toSet());
 
         logger.info("Disabling {} Controller Services", enabledServices.size());
-        final Pause disableServicesPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+        final CancellableTimedPause disableServicesPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+        asyncRequest.setCancelCallback(disableServicesPause::cancel);
         componentLifecycle.activateControllerServices(exampleUri, user, groupId, enabledServices, ControllerServiceState.DISABLED, disableServicesPause);
 
         if (asyncRequest.isCancelled()) {
@@ -1328,96 +1293,113 @@ public class VersionsResource extends ApplicationResource {
         logger.info("Updating Process Group with ID {} to version {} of the Versioned Flow", groupId, flowSnapshot.getSnapshotMetadata().getVersion());
         // If replicating request, steps 10-12 are performed on each node individually, and this is accomplished
         // by replicating a PUT to /nifi-api/versions/process-groups/{groupId}
-        if (replicateRequest) {
+        try {
+            if (replicateRequest) {
 
-            final URI updateUri;
+                final URI updateUri;
-            try {
+                try {
-                updateUri = new URI(exampleUri.getScheme(), exampleUri.getUserInfo(), exampleUri.getHost(),
+                    updateUri = new URI(exampleUri.getScheme(), exampleUri.getUserInfo(), exampleUri.getHost(),
-                    exampleUri.getPort(), "/nifi-api/versions/process-groups/" + groupId, null, exampleUri.getFragment());
+                        exampleUri.getPort(), "/nifi-api/versions/process-groups/" + groupId, null, exampleUri.getFragment());
-            } catch (URISyntaxException e) {
+                } catch (URISyntaxException e) {
-                throw new RuntimeException(e);
+                    throw new RuntimeException(e);
-            }
-
-            final Map<String, String> headers = new HashMap<>();
-            headers.put("content-type", MediaType.APPLICATION_JSON);
-
-            final VersionedFlowSnapshotEntity snapshotEntity = new VersionedFlowSnapshotEntity();
-            snapshotEntity.setProcessGroupRevision(requestEntity.getProcessGroupRevision());
-            snapshotEntity.setRegistryId(requestEntity.getVersionControlInformation().getRegistryId());
-            snapshotEntity.setVersionedFlow(flowSnapshot);
-
-            final NodeResponse clusterResponse;
-            try {
-                if (getReplicationTarget() == ReplicationTarget.CLUSTER_NODES) {
-                    clusterResponse = getRequestReplicator().replicate(user, HttpMethod.PUT, updateUri, snapshotEntity, headers).awaitMergedResponse();
-                } else {
-                    clusterResponse = getRequestReplicator().forwardToCoordinator(
-                        getClusterCoordinatorNode(), user, HttpMethod.PUT, updateUri, snapshotEntity, headers).awaitMergedResponse();
                 }
-            } catch (final InterruptedException ie) {
+
-                Thread.currentThread().interrupt();
+                final Map<String, String> headers = new HashMap<>();
-                throw new LifecycleManagementException("Interrupted while updating flows across cluster", ie);
+                headers.put("content-type", MediaType.APPLICATION_JSON);
+
+                final VersionedFlowSnapshotEntity snapshotEntity = new VersionedFlowSnapshotEntity();
+                snapshotEntity.setProcessGroupRevision(requestEntity.getProcessGroupRevision());
+                snapshotEntity.setRegistryId(requestEntity.getVersionControlInformation().getRegistryId());
+                snapshotEntity.setVersionedFlow(flowSnapshot);
+                snapshotEntity.setUpdateDescendantVersionedFlows(updateDescendantVersionedFlows);
+
+                final NodeResponse clusterResponse;
+                try {
+                    logger.debug("Replicating PUT request to {} for user {}", updateUri, user);
+
+                    if (getReplicationTarget() == ReplicationTarget.CLUSTER_NODES) {
+                        clusterResponse = getRequestReplicator().replicate(user, HttpMethod.PUT, updateUri, snapshotEntity, headers).awaitMergedResponse();
+                    } else {
+                        clusterResponse = getRequestReplicator().forwardToCoordinator(
+                            getClusterCoordinatorNode(), user, HttpMethod.PUT, updateUri, snapshotEntity, headers).awaitMergedResponse();
+                    }
+                } catch (final InterruptedException ie) {
+                    logger.warn("Interrupted while replicating PUT request to {} for user {}", updateUri, user);
+                    Thread.currentThread().interrupt();
+                    throw new LifecycleManagementException("Interrupted while updating flows across cluster", ie);
+                }
+
+                final int updateFlowStatus = clusterResponse.getStatus();
+                if (updateFlowStatus != Status.OK.getStatusCode()) {
+                    final String explanation = getResponseEntity(clusterResponse, String.class);
+                    logger.error("Failed to update flow across cluster when replicating PUT request to {} for user {}. Received {} response with explanation: {}",
+                        updateUri, user, updateFlowStatus, explanation);
+                    throw new LifecycleManagementException("Failed to update Flow on all nodes in cluster due to " + explanation);
+                }
+
+            } else {
+                // Step 10: Ensure that if any connection exists in the flow and does not exist in the proposed snapshot,
+                // that it has no data in it. Ensure that no Input Port was removed, unless it currently has no incoming connections.
+                // Ensure that no Output Port was removed, unless it currently has no outgoing connections.
+                serviceFacade.verifyCanUpdate(groupId, flowSnapshot, true, verifyNotModified);
+
+                // Step 11-12. Update Process Group to the new flow and update variable registry with any Variables that were added or removed
+                final RevisionDTO revisionDto = requestEntity.getProcessGroupRevision();
+                final Revision revision = new Revision(revisionDto.getVersion(), revisionDto.getClientId(), groupId);
+                final VersionControlInformationDTO requestVci = requestEntity.getVersionControlInformation();
+
+                final Bucket bucket = flowSnapshot.getBucket();
+                final VersionedFlow flow = flowSnapshot.getFlow();
+
+                final VersionedFlowSnapshotMetadata metadata = flowSnapshot.getSnapshotMetadata();
+                final VersionControlInformationDTO vci = new VersionControlInformationDTO();
+                vci.setBucketId(metadata.getBucketIdentifier());
+                vci.setBucketName(bucket.getName());
+                vci.setCurrent(flowSnapshot.isLatest());
+                vci.setFlowDescription(flow.getDescription());
+                vci.setFlowId(flow.getIdentifier());
+                vci.setFlowName(flow.getName());
+                vci.setGroupId(groupId);
+                vci.setModified(false);
+                vci.setRegistryId(requestVci.getRegistryId());
+                vci.setRegistryName(serviceFacade.getFlowRegistryName(requestVci.getRegistryId()));
+                vci.setVersion(metadata.getVersion());
+
+                serviceFacade.updateProcessGroupContents(user, revision, groupId, vci, flowSnapshot, idGenerationSeed, verifyNotModified, false, updateDescendantVersionedFlows);
+            }
+        } finally {
+            if (!asyncRequest.isCancelled()) {
+                if (logger.isDebugEnabled()) {
+                    logger.debug("Re-Enabling {} Controller Services: {}", enabledServices.size(), enabledServices);
+                }
+
+                asyncRequest.update(new Date(), "Re-Enabling Controller Services", 60);
+
+                // Step 13. Re-enable all disabled controller services
+                final CancellableTimedPause enableServicesPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+                asyncRequest.setCancelCallback(enableServicesPause::cancel);
+                final Set<AffectedComponentEntity> servicesToEnable = getUpdatedEntities(enabledServices, user);
+                logger.info("Successfully updated flow; re-enabling {} Controller Services", servicesToEnable.size());
+                componentLifecycle.activateControllerServices(exampleUri, user, groupId, servicesToEnable, ControllerServiceState.ENABLED, enableServicesPause);
             }
 
-            final int disableServicesStatus = clusterResponse.getStatus();
+            if (!asyncRequest.isCancelled()) {
-            if (disableServicesStatus != Status.OK.getStatusCode()) {
+                if (logger.isDebugEnabled()) {
-                final String explanation = getResponseEntity(clusterResponse, String.class);
+                    logger.debug("Restart {} Processors: {}", runningComponents.size(), runningComponents);
-                throw new LifecycleManagementException("Failed to update Flow on all nodes in cluster due to " + explanation);
+                }
+
+                asyncRequest.update(new Date(), "Restarting Processors", 80);
+
+                // Step 14. Restart all components
+                final Set<AffectedComponentEntity> componentsToStart = getUpdatedEntities(runningComponents, user);
+                final CancellableTimedPause startComponentsPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+                asyncRequest.setCancelCallback(startComponentsPause::cancel);
+                logger.info("Restarting {} Processors", componentsToStart.size());
+                componentLifecycle.scheduleComponents(exampleUri, user, groupId, componentsToStart, ScheduledState.RUNNING, startComponentsPause);
             }
-
-        } else {
-            // Step 10: Ensure that if any connection exists in the flow and does not exist in the proposed snapshot,
-            // that it has no data in it. Ensure that no Input Port was removed, unless it currently has no incoming connections.
-            // Ensure that no Output Port was removed, unless it currently has no outgoing connections.
-            serviceFacade.verifyCanUpdate(groupId, flowSnapshot, true, verifyNotModified);
-
-            // Step 11-12. Update Process Group to the new flow and update variable registry with any Variables that were added or removed
-            final RevisionDTO revisionDto = requestEntity.getProcessGroupRevision();
-            final Revision revision = new Revision(revisionDto.getVersion(), revisionDto.getClientId(), groupId);
-            final VersionControlInformationDTO requestVci = requestEntity.getVersionControlInformation();
-
-            final Bucket bucket = flowSnapshot.getBucket();
-            final VersionedFlow flow = flowSnapshot.getFlow();
-
-            final VersionedFlowSnapshotMetadata metadata = flowSnapshot.getSnapshotMetadata();
-            final VersionControlInformationDTO vci = new VersionControlInformationDTO();
-            vci.setBucketId(metadata.getBucketIdentifier());
-            vci.setBucketName(bucket.getName());
-            vci.setCurrent(flowSnapshot.isLatest());
-            vci.setFlowDescription(flow.getDescription());
-            vci.setFlowId(flow.getIdentifier());
-            vci.setFlowName(flow.getName());
-            vci.setGroupId(groupId);
-            vci.setModified(false);
-            vci.setRegistryId(requestVci.getRegistryId());
-            vci.setRegistryName(serviceFacade.getFlowRegistryName(requestVci.getRegistryId()));
-            vci.setVersion(metadata.getVersion());
-
-            serviceFacade.updateProcessGroupContents(user, revision, groupId, vci, flowSnapshot, idGenerationSeed, verifyNotModified, false);
         }
 
-        if (asyncRequest.isCancelled()) {
+        asyncRequest.setCancelCallback(null);
-            return null;
-        }
-        asyncRequest.update(new Date(), "Re-Enabling Controller Services", 60);
-
-        // Step 13. Re-enable all disabled controller services
-        final Pause enableServicesPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
-        final Set<AffectedComponentEntity> servicesToEnable = getUpdatedEntities(enabledServices, user);
-        logger.info("Successfully updated flow; re-enabling {} Controller Services", servicesToEnable.size());
-        componentLifecycle.activateControllerServices(exampleUri, user, groupId, servicesToEnable, ControllerServiceState.ENABLED, enableServicesPause);
-
-        if (asyncRequest.isCancelled()) {
-            return null;
-        }
-        asyncRequest.update(new Date(), "Restarting Processors", 80);
-
-        // Step 14. Restart all components
-        final Set<AffectedComponentEntity> componentsToStart = getUpdatedEntities(runningComponents, user);
-        final Pause startComponentsPause = new CancellableTimedPause(250, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
-        logger.info("Restarting {} Processors", componentsToStart.size());
-        componentLifecycle.scheduleComponents(exampleUri, user, groupId, componentsToStart, ScheduledState.RUNNING, startComponentsPause);
-
         if (asyncRequest.isCancelled()) {
             return null;
         }
@@ -1426,6 +1408,7 @@ public class VersionsResource extends ApplicationResource {
         return serviceFacade.getVersionControlInformation(groupId);
     }
 
+
     /**
      * Extracts the response entity from the specified node response.
      *

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/api/concurrent/AsynchronousWebRequest.java

@@ -99,4 +99,12 @@ public interface AsynchronousWebRequest<T> {
      * @return <code>true</code> if the request has been canceled, <code>false</code> otherwise
      */
     boolean isCancelled();
+
+    /**
+     * Sets the cancel callback to the given runnable, so that if {@link #cancel()} is called, the given {@link Runnable} will be triggered.
+     * If <code>null</code> is passed, no operation will be triggered when the task is cancelled.
+     *
+     * @param runnable the callback
+     */
+    void setCancelCallback(Runnable runnable);
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/api/concurrent/StandardAsynchronousWebRequest.java

@@ -34,6 +34,7 @@ public class StandardAsynchronousWebRequest<T> implements AsynchronousWebRequest
     private volatile String failureReason;
     private volatile boolean cancelled;
     private volatile T results;
+    private volatile Runnable cancelCallback;
 
     public StandardAsynchronousWebRequest(final String requestId, final String processGroupId, final NiFiUser user, final String state) {
         this.id = requestId;
@@ -56,6 +57,11 @@ public class StandardAsynchronousWebRequest<T> implements AsynchronousWebRequest
         return processGroupId;
     }
 
+    @Override
+    public void setCancelCallback(final Runnable runnable) {
+        this.cancelCallback = runnable;
+    }
+
     @Override
     public void markComplete(final T results) {
         this.complete = true;
@@ -130,6 +136,7 @@ public class StandardAsynchronousWebRequest<T> implements AsynchronousWebRequest
         percentComplete = 100;
         state = "Canceled by user";
         setFailureReason("Request cancelled by user");
+        cancelCallback.run();
     }
 
     @Override

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/api/dto/DtoFactory.java

@@ -118,6 +118,7 @@ import org.apache.nifi.registry.flow.VersionControlInformation;
 import org.apache.nifi.registry.flow.VersionedComponent;
 import org.apache.nifi.registry.flow.diff.FlowComparison;
 import org.apache.nifi.registry.flow.diff.FlowDifference;
+import org.apache.nifi.registry.flow.mapping.InstantiatedVersionedComponent;
 import org.apache.nifi.registry.flow.mapping.InstantiatedVersionedConnection;
 import org.apache.nifi.registry.flow.mapping.InstantiatedVersionedControllerService;
 import org.apache.nifi.registry.flow.mapping.InstantiatedVersionedFunnel;
@@ -2202,15 +2203,23 @@ public final class DtoFactory {
 
     private ComponentDifferenceDTO createComponentDifference(final FlowDifference difference) {
         VersionedComponent component = difference.getComponentA();
-        if (component == null) {
+        if (component == null || difference.getComponentB() instanceof InstantiatedVersionedComponent) {
             component = difference.getComponentB();
         }
 
         final ComponentDifferenceDTO dto = new ComponentDifferenceDTO();
-        dto.setComponentId(component.getIdentifier());
         dto.setComponentName(component.getName());
         dto.setComponentType(component.getComponentType().name());
-        dto.setProcessGroupId(dto.getProcessGroupId());
+
+        if (component instanceof InstantiatedVersionedComponent) {
+            final InstantiatedVersionedComponent instantiatedComponent = (InstantiatedVersionedComponent) component;
+            dto.setComponentId(instantiatedComponent.getInstanceId());
+            dto.setProcessGroupId(instantiatedComponent.getInstanceGroupId());
+        } else {
+            dto.setComponentId(component.getIdentifier());
+            dto.setProcessGroupId(dto.getProcessGroupId());
+        }
+
         return dto;
     }
 

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/dao/ProcessGroupDAO.java

@@ -114,10 +114,12 @@ public interface ProcessGroupDAO {
      * @param versionControlInformation the new Version Control Information
      * @param componentIdSeed the seed value to use for generating ID's for new components
      * @param updateSettings whether or not to update the process group's name and position
+     * @param updateDescendantVersionedFlows if a child/descendant Process Group is under Version Control, specifies whether or not to
+     *            update the contents of that Process Group
      * @return the process group
      */
     ProcessGroup updateProcessGroupFlow(String groupId, VersionedFlowSnapshot proposedSnapshot, VersionControlInformationDTO versionControlInformation, String componentIdSeed,
-        boolean verifyNotModified, boolean updateSettings);
+        boolean verifyNotModified, boolean updateSettings, boolean updateDescendantVersionedFlows);
 
     /**
      * Applies the given Version Control Information to the Process Group

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/dao/impl/StandardProcessGroupDAO.java

@@ -29,6 +29,8 @@ import org.apache.nifi.registry.flow.FlowRegistry;
 import org.apache.nifi.registry.flow.StandardVersionControlInformation;
 import org.apache.nifi.registry.flow.VersionControlInformation;
 import org.apache.nifi.registry.flow.VersionedFlowSnapshot;
+import org.apache.nifi.registry.flow.VersionedProcessGroup;
+import org.apache.nifi.registry.flow.mapping.NiFiRegistryFlowMapper;
 import org.apache.nifi.remote.RemoteGroupPort;
 import org.apache.nifi.web.ResourceNotFoundException;
 import org.apache.nifi.web.api.dto.ProcessGroupDTO;
@@ -244,8 +246,12 @@ public class StandardProcessGroupDAO extends ComponentDAO implements ProcessGrou
         final FlowRegistry flowRegistry = flowController.getFlowRegistryClient().getFlowRegistry(registryId);
         final String registryName = flowRegistry == null ? registryId : flowRegistry.getName();
 
+        final NiFiRegistryFlowMapper mapper = new NiFiRegistryFlowMapper();
+        final VersionedProcessGroup flowSnapshot = mapper.mapProcessGroup(group, flowController.getFlowRegistryClient(), false);
+
         final StandardVersionControlInformation vci = StandardVersionControlInformation.Builder.fromDto(versionControlInformation)
             .registryName(registryName)
+            .flowSnapshot(flowSnapshot)
             .modified(false)
             .current(true)
             .build();
@@ -264,9 +270,9 @@ public class StandardProcessGroupDAO extends ComponentDAO implements ProcessGrou
 
     @Override
     public ProcessGroup updateProcessGroupFlow(final String groupId, final VersionedFlowSnapshot proposedSnapshot, final VersionControlInformationDTO versionControlInformation,
-        final String componentIdSeed, final boolean verifyNotModified, final boolean updateSettings) {
+        final String componentIdSeed, final boolean verifyNotModified, final boolean updateSettings, final boolean updateDescendantVersionedFlows) {
         final ProcessGroup group = locateProcessGroup(flowController, groupId);
-        group.updateFlow(proposedSnapshot, componentIdSeed, verifyNotModified, updateSettings);
+        group.updateFlow(proposedSnapshot, componentIdSeed, verifyNotModified, updateSettings, updateDescendantVersionedFlows);
 
         final StandardVersionControlInformation svci = StandardVersionControlInformation.Builder.fromDto(versionControlInformation)
             .flowSnapshot(proposedSnapshot.getFlowContents())

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/util/CancellableTimedPause.java

@@ -43,7 +43,7 @@ public class CancellableTimedPause implements Pause {
 
         long sysTime = System.nanoTime();
         final long maxWaitTime = System.nanoTime() + pauseNanos;
-        while (sysTime < maxWaitTime) {
+        while (sysTime < maxWaitTime && !cancelled) {
             try {
                 TimeUnit.NANOSECONDS.sleep(pauseNanos);
             } catch (final InterruptedException ie) {

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/util/SnippetUtils.java

@@ -421,18 +421,24 @@ public final class SnippetUtils {
         }
 
         // get a list of all names of process groups so that we can rename as needed.
-        final List<String> groupNames = new ArrayList<>();
+        final Set<String> groupNames = new HashSet<>();
         for (final ProcessGroup childGroup : group.getProcessGroups()) {
             groupNames.add(childGroup.getName());
         }
 
         if (snippetContents.getProcessGroups() != null) {
             for (final ProcessGroupDTO groupDTO : snippetContents.getProcessGroups()) {
-                String groupName = groupDTO.getName();
+                // If Version Control Information is present, then we don't want to rename the
-                while (groupNames.contains(groupName)) {
+                // Process Group - we want it to remain the same as the one in Version Control.
-                    groupName = "Copy of " + groupName;
+                // However, in order to disambiguate things, we generally do want to rename to
+                // 'Copy of...' so we do this only if there is no Version Control Information present.
+                if (groupDTO.getVersionControlInformation() == null) {
+                    String groupName = groupDTO.getName();
+                    while (groupNames.contains(groupName)) {
+                        groupName = "Copy of " + groupName;
+                    }
+                    groupDTO.setName(groupName);
                 }
-                groupDTO.setName(groupName);
                 groupNames.add(groupDTO.getName());
             }
         }