chore: 16380 MerkleStateRoot clean up (#16381)

Signed-off-by: Ivan Malygin <[email protected]>

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/state/MerkleStateRoot.java

@@ -17,9 +17,7 @@
 package com.swirlds.platform.state;
 
 import static com.swirlds.logging.legacy.LogMarker.EXCEPTION;
-import static com.swirlds.logging.legacy.LogMarker.STARTUP;
 import static com.swirlds.platform.state.MerkleStateUtils.createInfoString;
-import static com.swirlds.platform.state.service.PbjConverter.toPbjPlatformState;
 import static com.swirlds.platform.state.service.schemas.V0540PlatformStateSchema.PLATFORM_STATE_KEY;
 import static com.swirlds.platform.system.InitTrigger.EVENT_STREAM_RECOVERY;
 import static com.swirlds.state.StateChangeListener.StateType.MAP;
@@ -186,16 +184,6 @@ public class MerkleStateRoot extends PartialNaryMerkleInternal
      */
     private final RuntimeObjectRecord registryRecord;
 
-    /**
-     * If set, the platform state from a deserialized state created prior to version 0.54, and used to initialize
-     * the platform state as a State API singleton after migration.
-     *
-     * @deprecated since 0.54.0; this field should be removed in a future release
-     */
-    @Nullable
-    @Deprecated(forRemoval = true)
-    private PlatformState preV054PlatformState;
-
     /**
      * Create a new instance. This constructor must be used for all creations of this class.
      *
@@ -210,14 +198,6 @@ public MerkleStateRoot(
         this.versionFactory = requireNonNull(versionFactory);
     }
 
-    /**
-     * Returns the platform state found at child index 0 of a pre-0.54 state, or null if not found.
-     * @return the pre-0.54 platform state, or null if not found
-     */
-    public @Nullable PlatformState getPreV054PlatformState() {
-        return preV054PlatformState;
-    }
-
     /**
      * {@inheritDoc}
      * <p>
@@ -273,7 +253,6 @@ protected MerkleStateRoot(@NonNull final MerkleStateRoot from) {
         this.lifecycles = from.lifecycles;
         this.registryRecord = RuntimeObjectRegistry.createRecord(getClass());
         this.versionFactory = from.versionFactory;
-        this.preV054PlatformState = from.preV054PlatformState;
         this.listeners.addAll(from.listeners);
 
         // Copy over the metadata
@@ -302,6 +281,11 @@ public int getVersion() {
         return CURRENT_VERSION;
     }
 
+    @Override
+    public int getMinimumSupportedVersion() {
+        return CURRENT_VERSION;
+    }
+
     /**
      * To be called ONLY at node shutdown. Attempts to gracefully close any virtual maps. This method is a bit of a
      * hack, ideally there would be something more generic at the platform level that virtual maps could hook into
@@ -406,43 +390,12 @@ public void preHandle(@NonNull final Event event) {
         lifecycles.onPreHandle(event, this);
     }
 
-    /**
-     * {@inheritDoc}
-     */
     @Override
-    public MerkleNode migrate(final int version) {
-
-        if (version < CURRENT_VERSION) {
-            PlatformState platformState = null;
-            int platformStateIndex = -1;
-            for (int i = 0; i < getNumberOfChildren(); i++) {
-                if (getChild(i) instanceof PlatformState ps) {
-                    platformState = ps;
-                    platformStateIndex = i;
-                    break;
-                }
-            }
-            if (platformState == null) {
-                throw new IllegalStateException("Expected MerkleStateRoot to have PlatformState as a child");
-            }
-
-            preV054PlatformState = platformState;
-            logger.info(STARTUP.getMarker(), "Found pre-0.54 PlatformState, will migrate to State API singleton");
-            INDEX_LOOKUP.clear();
-            final List<MerkleNode> newChildren = new ArrayList<>();
-            for (int i = 0, n = getNumberOfChildren(); i < n; i++) {
-                // Skip the platform state, it will be added later
-                if (i == platformStateIndex) {
-                    continue;
-                }
-                final var child = getChild(i);
-                if (child != null) {
-                    newChildren.add(child.copy());
-                }
-            }
-            addDeserializedChildren(newChildren, CURRENT_VERSION);
+    public MerkleNode migrate(int version) {
+        if (version < getMinimumSupportedVersion()) {
+            throw new UnsupportedOperationException("State migration from version " + version + " is not supported."
+                    + " The minimum supported version is " + getMinimumSupportedVersion());
         }
-        // Always return this node, we never want to replace MerkleStateRoot node in the tree
         return this;
     }
 
@@ -1059,16 +1012,7 @@ private ReadablePlatformStateStore readablePlatformStateStore() {
     }
 
     private WritablePlatformStateStore writablePlatformStateStore() {
-        final var store = new WritablePlatformStateStore(getWritableStates(PlatformStateService.NAME), versionFactory);
-        if (preV054PlatformState != null) {
-            store.setAllFrom(preV054PlatformState);
-            logger.info(
-                    STARTUP.getMarker(),
-                    "Migrated PlatformState {} to State API singleton",
-                    toPbjPlatformState(preV054PlatformState));
-            preV054PlatformState = null;
-        }
-        return store;
+        return new WritablePlatformStateStore(getWritableStates(PlatformStateService.NAME), versionFactory);
     }
 
     /**

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/state/service/PlatformStateService.java

@@ -67,12 +67,8 @@ public SemanticVersion creationVersionOf(@NonNull final MerkleStateRoot root) {
         }
         final var index = root.findNodeIndex(NAME, PLATFORM_STATE_KEY);
         if (index == -1) {
-            final var legacyPlatformState = requireNonNull(root.getPreV054PlatformState());
-            return legacyPlatformState.getCreationSoftwareVersion().getPbjSemanticVersion();
-        } else {
-            return ((SingletonNode<PlatformState>) root.getChild(index))
-                    .getValue()
-                    .creationSoftwareVersionOrThrow();
+            throw new IllegalStateException("Platform state not found in root");
         }
+        return ((SingletonNode<PlatformState>) root.getChild(index)).getValue().creationSoftwareVersionOrThrow();
     }
 }

platform-sdk/swirlds-platform-core/src/test/java/com/swirlds/platform/state/MerkleStateRootTest.java

@@ -960,13 +960,6 @@ void testUpdatePlatformStateData() {
     @Nested
     @DisplayName("Migrate test")
     class MigrateTest {
-        @Test
-        @DisplayName("Migrate fails if the first child is not PlatformState")
-        void migrate_fail() {
-            stateRoot.putServiceStateIfAbsent(fruitMetadata, () -> fruitMerkleMap);
-            assertThrows(IllegalStateException.class, () -> stateRoot.migrate(CURRENT_VERSION - 1));
-        }
-
         @Test
         @DisplayName("If the version is current, nothing ever happens")
         void migrate_currentVersion() {
@@ -980,14 +973,9 @@ void migrate_currentVersion() {
         }
 
         @Test
-        @DisplayName("Migrate fails if the platform state is absent")
-        void migrate_platform_absent() {
-            var node1 = mock(MerkleNode.class);
-            stateRoot.setChild(0, node1);
-            var node2 = mock(MerkleNode.class);
-            stateRoot.setChild(1, node2);
-
-            assertThrows(IllegalStateException.class, () -> stateRoot.migrate(CURRENT_VERSION - 1));
+        @DisplayName("Migration from previous versions is not supported")
+        void migration_not_supported() {
+            assertThrows(UnsupportedOperationException.class, () -> stateRoot.migrate(CURRENT_VERSION - 1));
         }
     }
 

platform-sdk/swirlds-platform-core/src/test/java/com/swirlds/platform/state/service/PlatformStateServiceTest.java

@@ -70,22 +70,12 @@ void emptyRootIsAtGenesis() {
     }
 
     @Test
-    void rootWithNoPlatformStateAndLegacyStateAtChildZeroGetsLegacyVersion() {
+    void rootWithNoPlatformState_throwsException() {
         given(root.getNumberOfChildren()).willReturn(1);
         given(root.findNodeIndex(PlatformStateService.NAME, V0540PlatformStateSchema.PLATFORM_STATE_KEY))
                 .willReturn(-1);
-        given(root.getPreV054PlatformState()).willReturn(legacyState);
-        given(legacyState.getCreationSoftwareVersion()).willReturn(version);
-        given(version.getPbjSemanticVersion()).willReturn(SemanticVersion.DEFAULT);
-        assertSame(SemanticVersion.DEFAULT, PLATFORM_STATE_SERVICE.creationVersionOf(root));
-    }
 
-    @Test
-    void rootWithNoPlatformStateMustHaveLegacyStateAtChildZero() {
-        given(root.getNumberOfChildren()).willReturn(1);
-        given(root.findNodeIndex(PlatformStateService.NAME, V0540PlatformStateSchema.PLATFORM_STATE_KEY))
-                .willReturn(-1);
-        assertThrows(NullPointerException.class, () -> PLATFORM_STATE_SERVICE.creationVersionOf(root));
+        assertThrows(IllegalStateException.class, () -> PLATFORM_STATE_SERVICE.creationVersionOf(root));
     }
 
     @Test