Implement #6723

modules/dcache-resilience/src/test/java/org/dcache/resilience/TestSelectionUnit.java

@@ -169,6 +169,11 @@ public Collection<SelectionPool> getPoolsByPoolGroup(String poolGroup)
         return psu.getPoolsByPoolGroup(poolGroup);
     }
 
+    @Override
+    public Collection<SelectionPool> getPoolsBySourcePoolPoolGroup(String sourcePool) throws NoSuchElementException {
+        return psu.getPoolsBySourcePoolPoolGroup(sourcePool);
+    }
+
     @Override
     public String getProtocolUnit(String protocolUnitName) {
         return psu.getProtocolUnit(protocolUnitName);

modules/dcache-vehicles/src/main/java/diskCacheV111/vehicles/PoolManagerGetPoolsBySourcePoolPoolGroupMessage.java

@@ -0,0 +1,19 @@
+package diskCacheV111.vehicles;
+
+import static java.util.Objects.requireNonNull;
+
+public class PoolManagerGetPoolsBySourcePoolPoolGroupMessage
+      extends PoolManagerGetPoolsMessage {
+
+    private static final long serialVersionUID = 4423670920097918847L;
+
+    private final String _sourcePool;
+
+    public PoolManagerGetPoolsBySourcePoolPoolGroupMessage(String sourcePool) {
+        _sourcePool = requireNonNull(sourcePool);
+    }
+
+    public String getSourcePool() {
+        return _sourcePool;
+    }
+}

modules/dcache/src/main/java/diskCacheV111/poolManager/PoolManagerV5.java

@@ -18,6 +18,7 @@
 import diskCacheV111.vehicles.PoolManagerGetPoolsByLinkMessage;
 import diskCacheV111.vehicles.PoolManagerGetPoolsByNameMessage;
 import diskCacheV111.vehicles.PoolManagerGetPoolsByPoolGroupMessage;
+import diskCacheV111.vehicles.PoolManagerGetPoolsBySourcePoolPoolGroupMessage;
 import diskCacheV111.vehicles.PoolManagerPoolInformation;
 import diskCacheV111.vehicles.PoolManagerPoolModeMessage;
 import diskCacheV111.vehicles.PoolManagerPoolUpMessage;
@@ -524,6 +525,25 @@ private void getPoolInformation(
         return msg;
     }
 
+    public PoolManagerGetPoolsBySourcePoolPoolGroupMessage
+    messageArrived(PoolManagerGetPoolsBySourcePoolPoolGroupMessage msg) {
+        try {
+            List<PoolManagerPoolInformation> pools = new ArrayList<>();
+            List<String> offlinePools = new ArrayList<>();
+            getPoolInformation(_selectionUnit.getPoolsBySourcePoolPoolGroup(msg.getSourcePool()), pools,
+                      offlinePools);
+            msg.setPools(pools);
+            msg.setOfflinePools(offlinePools);
+            msg.setSucceeded();
+        } catch (NoSuchElementException e) {
+            Collection<PoolManagerPoolInformation> empty =
+                  Collections.emptyList();
+            msg.setPools(empty);
+            msg.setSucceeded();
+        }
+        return msg;
+    }
+
     public PoolManagerGetPoolsByPoolGroupMessage
     messageArrived(PoolManagerGetPoolsByPoolGroupMessage msg) {
         try {

modules/dcache/src/main/java/diskCacheV111/poolManager/PoolSelectionUnit.java

@@ -282,6 +282,8 @@ boolean updatePool(String poolName, CellAddressCore address, String canonicalHos
 
     Collection<SelectionPool> getPoolsByPoolGroup(String poolGroup) throws NoSuchElementException;
 
+    Collection<SelectionPool> getPoolsBySourcePoolPoolGroup(String sourcePool) throws NoSuchElementException;
+
     Collection<SelectionPool> getAllDefinedPools(boolean enabledOnly);
 
     Collection<SelectionPoolGroup> getPoolGroupsOfPool(String PoolName);

modules/dcache/src/main/java/diskCacheV111/poolManager/PoolSelectionUnitV2.java

@@ -2622,6 +2622,25 @@ public Collection<SelectionPool> getPoolsByPoolGroup(String poolGroup)
         return new ArrayList<>(group._poolList.values());
     }
 
+    @Override
+    public Collection<SelectionPool> getPoolsBySourcePoolPoolGroup(String sourcePool)
+          throws NoSuchElementException {
+        Collection<SelectionPoolGroup> groups;
+        try {
+            groups = getPoolGroupsOfPool(sourcePool);
+        } catch (NoSuchElementException e) {
+            throw new NoSuchElementException("No pool group for nonexistent source pool: " + sourcePool);
+        }
+
+        if (groups.isEmpty()) {
+            throw new NoSuchElementException("No pool group for source pool: " + sourcePool);
+        } else if (groups.size() > 1) {
+            throw new NoSuchElementException("No unique pool group for source pool: " + sourcePool);
+        }
+
+        return new ArrayList<>(groups.iterator().next().getPools());
+    }
+
     @Override
     public Collection<SelectionPool> getAllDefinedPools(boolean enabledOnly) {
         List<SelectionPool> pools = new ArrayList<>(_pools.size());

modules/dcache/src/main/java/org/dcache/pool/migration/MigrationModule.java

@@ -487,7 +487,7 @@ public class MigrationCopyCommand implements Callable<String> {
         @Option(name = "target", values = {"pool", "pgroup", "link", "hsm"},
               category = "Target options",
               usage = "Determines the interpretation of the target names.")
-        String target = "pool";
+        String target = null;
 
         @Option(name = "meta-only",
               category = "Target options",
@@ -545,7 +545,12 @@ public class MigrationCopyCommand implements Callable<String> {
 
         private RefreshablePoolList createPoolList(String type, List<String> targets) {
             CellStub poolManager = _context.getPoolManagerStub();
-
+            if (type == null) {
+                type = "pgroup";
+                if (targets.isEmpty()) {
+                    return new PoolListBySourcePoolPoolGroup(poolManager, _context.getPoolName());
+                }
+            }
             switch (type) {
                 case "pool":
                     return new PoolListByNames(poolManager, targets);

modules/dcache/src/main/java/org/dcache/pool/migration/PoolListBySourcePoolPoolGroup.java

@@ -0,0 +1,32 @@
+package org.dcache.pool.migration;
+
+import static java.util.Objects.requireNonNull;
+
+import com.google.common.util.concurrent.MoreExecutors;
+import diskCacheV111.vehicles.PoolManagerGetPoolsBySourcePoolPoolGroupMessage;
+import org.dcache.cells.CellStub;
+
+class PoolListBySourcePoolPoolGroup
+      extends PoolListFromPoolManager {
+
+    private final CellStub _poolManager;
+    private final String _sourcePool;
+
+    public PoolListBySourcePoolPoolGroup(CellStub poolManager, String sourcePool) {
+        _poolManager = requireNonNull(poolManager);
+        _sourcePool = requireNonNull(sourcePool);
+    }
+
+    @Override
+    public void refresh() {
+        CellStub.addCallback(
+              _poolManager.send(new PoolManagerGetPoolsBySourcePoolPoolGroupMessage(_sourcePool)),
+              this, MoreExecutors.directExecutor());
+    }
+
+    @Override
+    public String toString() {
+        return String.format("source pool %s, %d pools",
+              _sourcePool, _pools.size());
+    }
+}