Fix ReferenceTerminals and SlackTerminal iIDM extension with merged n…

…etworks and subnetworks (#3076)

* Fix ReferenceTerminals and SlackTerminal iIDM extension with merged networks and subnetworks

Signed-off-by: Damien Jeandemange <damien.jeandemange@artelys.com>
(cherry picked from commit 6401496)

iidm/iidm-extensions/src/main/java/com/powsybl/iidm/network/extensions/ReferenceTerminals.java

@@ -39,7 +39,7 @@ default String getName() {
     ReferenceTerminals addReferenceTerminal(Terminal terminal);
 
     /**
-     * Deletes all defined reference terminals in the network for the current variant
+     * Deletes all defined reference terminals in the network and all its subnetworks for the current variant
      * @param network network whose reference terminals should be deleted
      */
     static void reset(Network network) {
@@ -51,10 +51,13 @@ static void reset(Network network) {
                     .add();
         }
         ext.reset();
+        // reset also all subnetworks
+        network.getSubnetworks().forEach(ReferenceTerminals::reset);
     }
 
     /**
-     * Defines/add a terminal as reference in the network for the current variant
+     * Defines/add a terminal as reference in the network for the current variant.
+     * In case of a merged network with subnetwork, the extension is placed on the root/merged network.
      * @param terminal terminal to be added as reference terminal
      */
     static void addTerminal(Terminal terminal) {
@@ -70,7 +73,10 @@ static void addTerminal(Terminal terminal) {
     }
 
     /**
-     * Gets the reference terminals in the network for the current variant
+     * Gets the reference terminals in the network for the current variant.
+     * <p> Note: This method returns only the terminal from the extension attached to the provided network.
+     * In case of a merged network with subnetworks, be careful whether you want the extension
+     * of the merged network or of a subnetwork.</p>
      * @param network network to get reference terminals from
      */
     static Set<Terminal> getTerminals(Network network) {

iidm/iidm-extensions/src/main/java/com/powsybl/iidm/network/extensions/SlackTerminal.java

@@ -25,13 +25,16 @@ public interface SlackTerminal extends Extension<VoltageLevel> {
     String NAME = "slackTerminal";
 
     /**
-     * Set the terminal of all SlackTerminal extensions from the given network to null. If the extension is empty,
-     * meaning that for each variant the terminal is null, this method automatically remove the extension.
+     * Set the terminal of all SlackTerminal extensions from the given network and all its subnetworks to null.
+     * If the extension is empty, meaning that for each variant the terminal is null, this method automatically
+     * remove the extension.
      *
      * @param network A network to cleanup
      */
     static void reset(Network network) {
         network.getVoltageLevels().forEach(vl -> reset(vl, null));
+        // reset also all subnetworks
+        network.getSubnetworks().forEach(sn -> sn.getVoltageLevels().forEach(vl -> reset(vl, null)));
     }
 
     /**

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/extensions/ReferenceTerminalsImpl.java

@@ -22,7 +22,7 @@ class ReferenceTerminalsImpl extends AbstractMultiVariantIdentifiableExtension<N
 
     private final class ReferenceTerminalsListener extends DefaultNetworkListener {
         @Override
-        public void beforeRemoval(Identifiable identifiable) {
+        public void beforeRemoval(Identifiable<?> identifiable) {
             if (identifiable instanceof Connectable<?> connectable) {
                 // if connectable removed from network, remove its terminals from this extension
                 terminalsPerVariant.forEach(referenceTerminals -> connectable.getTerminals().forEach(referenceTerminals::remove));
@@ -39,12 +39,21 @@ public ReferenceTerminalsImpl(Network network, Set<Terminal> terminals) {
                 Collections.nCopies(getVariantManagerHolder().getVariantManager().getVariantArraySize(), new LinkedHashSet<>()));
         setReferenceTerminals(terminals);
         this.referenceTerminalsListener = new ReferenceTerminalsListener();
-        network.addListener(this.referenceTerminalsListener);
+    }
+
+    @Override
+    public void setExtendable(Network extendable) {
+        super.setExtendable(extendable);
+        if (extendable != null) {
+            // Add the listener, this will be done both extension creation, but also on extension transfer when merging and detaching.
+            extendable.getNetwork().addListener(this.referenceTerminalsListener);
+        }
     }
 
     @Override
     protected void cleanup() {
-        getExtendable().removeListener(this.referenceTerminalsListener);
+        // when extension removed from extendable, remove the listener. This will happen when merging and detaching.
+        getExtendable().getNetwork().removeListener(this.referenceTerminalsListener);
     }
 
     @Override
@@ -103,9 +112,19 @@ public void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
     }
 
     private static void checkTerminalInNetwork(Terminal terminal, Network network) {
-        if (!terminal.getVoltageLevel().getNetwork().equals(network)) {
-            throw new PowsyblException("Terminal given is not in the right Network ("
-                    + terminal.getVoltageLevel().getNetwork().getId() + " instead of " + network.getId() + ")");
+        final boolean extendableIsRootNetwork = network.getNetwork().equals(network);
+        if (extendableIsRootNetwork) {
+            // it is all fine as long as the terminal belongs to the merged network
+            if (!terminal.getVoltageLevel().getNetwork().equals(network)) {
+                throw new PowsyblException("Terminal given is not in the right Network ("
+                        + terminal.getVoltageLevel().getNetwork().getId() + " instead of " + network.getId() + ")");
+            }
+        } else {
+            // subnetwork: the terminal must be in the subnetwork
+            if (!terminal.getVoltageLevel().getParentNetwork().equals(network)) {
+                throw new PowsyblException("Terminal given is not in the right Network ("
+                        + terminal.getVoltageLevel().getParentNetwork().getId() + " instead of " + network.getId() + ")");
+            }
         }
     }
 }

iidm/iidm-tck/src/test/java/com/powsybl/iidm/network/tck/extensions/AbstractReferenceTerminalsTest.java

@@ -184,9 +184,9 @@ public void testVariantsCloning() {
     public void testWrongNetwork() {
         Network other = EurostagTutorialExample1Factory.create();
         Terminal terminal = other.getBusBreakerView().getBus("NHV1").getConnectedTerminals().iterator().next();
-        PowsyblException ex1 = assertThrows(PowsyblException.class, () -> network.newExtension(ReferenceTerminalsAdder.class)
-                .withTerminals(Set.of(terminal))
-                .add());
+        ReferenceTerminalsAdder referenceTerminalsAdder = network.newExtension(ReferenceTerminalsAdder.class)
+                .withTerminals(Set.of(terminal));
+        PowsyblException ex1 = assertThrows(PowsyblException.class, referenceTerminalsAdder::add);
         assertEquals("Terminal given is not in the right Network (sim1 instead of fourSubstations)", ex1.getMessage());
         network.newExtension(ReferenceTerminalsAdder.class)
                 .withTerminals(Set.of())
@@ -196,6 +196,77 @@ public void testWrongNetwork() {
         assertEquals("Terminal given is not in the right Network (sim1 instead of fourSubstations)", ex2.getMessage());
     }
 
+    @Test
+    public void testWithSubnetwork() {
+        Network merged = Network.merge(network, EurostagTutorialExample1Factory.create());
+        Network subnetwork = merged.getSubnetwork("fourSubstations");
+        Network sim1subnetwork = merged.getSubnetwork("sim1");
+        gh1 = merged.getGenerator("GH1");
+        gh2 = merged.getGenerator("GH2");
+        Terminal gh1Terminal = gh1.getTerminal();
+        Terminal gh2Terminal = gh2.getTerminal();
+
+        // gh1 is in subnetwork and can be added to subnetwork extension
+        subnetwork.newExtension(ReferenceTerminalsAdder.class)
+                .withTerminals(Set.of(gh1Terminal))
+                .add();
+        ReferenceTerminals extSubnetwork = subnetwork.getExtension(ReferenceTerminals.class);
+        assertEquals(1, extSubnetwork.getReferenceTerminals().size());
+        assertTrue(extSubnetwork.getReferenceTerminals().contains(gh1Terminal));
+
+        // gh2 is in subnetwork and can be added to root network extension
+        merged.newExtension(ReferenceTerminalsAdder.class)
+                .withTerminals(Set.of(gh2Terminal))
+                .add();
+        ReferenceTerminals extMergedNetwork = merged.getExtension(ReferenceTerminals.class);
+        assertEquals(1, extMergedNetwork.getReferenceTerminals().size());
+        assertTrue(extMergedNetwork.getReferenceTerminals().contains(gh2Terminal));
+
+        // we can reset everything via this method
+        ReferenceTerminals.reset(merged);
+        assertTrue(ReferenceTerminals.getTerminals(merged).isEmpty());
+
+        // we can add easily to merged/root network via this method
+        ReferenceTerminals.addTerminal(gh1Terminal);
+        extMergedNetwork = merged.getExtension(ReferenceTerminals.class);
+        extSubnetwork = subnetwork.getExtension(ReferenceTerminals.class);
+        assertEquals(1, extMergedNetwork.getReferenceTerminals().size());
+        assertEquals(0, extSubnetwork.getReferenceTerminals().size()); // not added to subnetwork
+        // same as above, but using the more user-friendly static methods from ReferenceTerminals.
+        assertEquals(1, ReferenceTerminals.getTerminals(merged).size());
+        assertEquals(0, ReferenceTerminals.getTerminals(subnetwork).size());
+
+        // we can't add gh1 to sim1
+        sim1subnetwork.newExtension(ReferenceTerminalsAdder.class)
+                .withTerminals(Set.of())
+                .add();
+        ReferenceTerminals extSim1 = sim1subnetwork.getExtension(ReferenceTerminals.class);
+        PowsyblException ex = assertThrows(PowsyblException.class, () -> extSim1.addReferenceTerminal(gh1Terminal));
+        assertEquals("Terminal given is not in the right Network (fourSubstations instead of sim1)", ex.getMessage());
+    }
+
+    @Test
+    public void testListenersTransferOnMergeAndDetach() {
+        Network network1 = FourSubstationsNodeBreakerFactory.create();
+        Network network2 = EurostagTutorialExample1Factory.create();
+        ReferenceTerminals.addTerminal(network1.getGenerator("GH1").getTerminal());
+        ReferenceTerminals.addTerminal(network1.getGenerator("GH2").getTerminal());
+
+        Network merged = Network.merge(network1, network2);
+        network1 = merged.getSubnetwork("fourSubstations");
+
+        // check listener is now effective on merged network
+        assertEquals(2, ReferenceTerminals.getTerminals(network1).size());
+        merged.getGenerator("GH1").remove();
+        assertEquals(1, ReferenceTerminals.getTerminals(network1).size());
+
+        Network network1detached = network1.detach();
+        // check listener is now effective on detached network
+        assertEquals(1, ReferenceTerminals.getTerminals(network1detached).size());
+        network1detached.getGenerator("GH2").remove();
+        assertEquals(0, ReferenceTerminals.getTerminals(network1detached).size());
+    }
+
     @Test
     public void testRemoveEquipment() {
         network.newExtension(ReferenceTerminalsAdder.class)

iidm/iidm-tck/src/test/java/com/powsybl/iidm/network/tck/extensions/AbstractSlackTerminalTest.java

@@ -51,10 +51,6 @@ static Network createBusBreakerNetwork() {
             .setQ0(50)
             .add();
 
-        Substation s1 = network.newSubstation()
-            .setId("S1")
-            .setCountry(Country.FR)
-            .add();
         VoltageLevel vl1 = s.newVoltageLevel()
             .setId("VL1")
             .setNominalV(400)
@@ -260,4 +256,32 @@ public void variantsResetTest() {
         assertNull(vlhv1.getExtension(SlackTerminal.class));
 
     }
+
+    @Test
+    public void testWithSubnetwork() {
+        Network network1 = createBusBreakerNetwork();
+        SlackTerminal.attach(network1.getBusBreakerView().getBus("B"));
+        Network network2 = EurostagTutorialExample1Factory.create();
+        SlackTerminal.attach(network2.getBusBreakerView().getBus("NHV1"));
+
+        Network merged = Network.merge(network1, network2);
+        network1 = merged.getSubnetwork("test");
+        network2 = merged.getSubnetwork("sim1");
+
+        // still there after merge
+        assertNotNull(merged.getVoltageLevel("VL").getExtension(SlackTerminal.class));
+        assertNotNull(merged.getVoltageLevel("VLHV1").getExtension(SlackTerminal.class));
+
+        // we can reset everything (including subnetworks)
+        SlackTerminal.reset(merged);
+        assertNull(merged.getVoltageLevel("VL").getExtension(SlackTerminal.class));
+        assertNull(merged.getVoltageLevel("VLHV1").getExtension(SlackTerminal.class));
+
+        // we can reset only a subnetwork
+        SlackTerminal.attach(network1.getBusBreakerView().getBus("B"));
+        SlackTerminal.attach(network2.getBusBreakerView().getBus("NHV1"));
+        SlackTerminal.reset(network1);
+        assertNull(merged.getVoltageLevel("VL").getExtension(SlackTerminal.class)); // reset
+        assertNotNull(merged.getVoltageLevel("VLHV1").getExtension(SlackTerminal.class)); // untouched
+    }
 }