Fix revisionless rebuilding and db reload. Fix 1.21 Adventure issues

Author: GoodrichDev

changelog/6.1.1.md

@@ -0,0 +1,5 @@
+## Paper, Folia, and reliability
+- Restored `/hdb info` and other component messages on Paper 1.21.x by compiling
+  against the Adventure API supplied by the minimum supported Paper release.
+- Prevented unchanged revisionless/custom catalog snapshots from rebuilding menus
+  and preloading every head on each scheduled synchronization.

headdb-core/src/main/java/com/bitworksmc/headdb/core/HeadDB.java

@@ -119,10 +119,12 @@ public void onEnable() {
         if (config.isUpdaterEnabled()) {
             long syncIntervalTicks = config.getDatabaseSyncIntervalMinutes() * 60L * 20L;
             Compatibility.runAsyncRepeating(this, () -> {
-                    int previousRevision = this.headDatabase.getCatalogRevision();
+                    List<Head> previousHeads = this.headDatabase.getHeads();
                     this.headDatabase.update().thenAcceptAsync(heads -> {
-                        int currentRevision = this.headDatabase.getCatalogRevision();
-                        if (currentRevision != previousRevision || currentRevision < 0) {
+                        // BaseHeadDatabase retains the published list when a full
+                        // snapshot is unchanged. This also works for custom sources
+                        // that do not expose managed catalog revision headers.
+                        if (heads != previousHeads) {
                             handleDatabaseUpdate(this.configManager.getConfig(), heads);
                             this.menuManager.registerDefaults(this, heads);
                         }

headdb-core/src/main/java/com/bitworksmc/headdb/implementation/BaseHeadDatabase.java

@@ -161,15 +161,17 @@ private List<Head> loadFullSnapshot() {
         for (String sourceUrl : sourceUrls) {
             try {
                 FetchedCatalog fetched = fetchHeads(sourceUrl);
-                Snapshot loadedSnapshot = buildSnapshot(fetched.heads());
-                this.snapshot = loadedSnapshot;
+                Snapshot currentSnapshot = this.snapshot;
+                if (!sameHeads(currentSnapshot, fetched.heads())) {
+                    this.snapshot = buildSnapshot(fetched.heads());
+                }
                 this.catalogRevision = fetched.revision();
                 this.activeSource = sourceUrl;
-                persistCatalogCache(loadedSnapshot.heads(), fetched.revision());
+                persistCatalogCache(this.snapshot.heads(), fetched.revision());
 
                 long elapsed = System.currentTimeMillis() - start;
                 LOGGER.debug("Update took {} seconds ({}ms total)", TimeUnit.MILLISECONDS.toSeconds(elapsed), elapsed);
-                return loadedSnapshot.heads();
+                return this.snapshot.heads();
             } catch (IOException | RuntimeException ex) {
                 lastException = ex;
                 LOGGER.warn("Failed to load heads from '{}': {}", sourceUrl, ex.getMessage());
@@ -724,6 +726,19 @@ private static boolean sameHead(Head left, Head right) {
                 && Objects.equals(left.getTags(), right.getTags());
     }
 
+    private static boolean sameHeads(@Nullable Snapshot left, List<Head> right) {
+        if (left == null || left.heads().size() != right.size()) {
+            return false;
+        }
+        for (int i = 0; i < left.heads().size(); i++) {
+            Head candidate = right.get(i);
+            if (candidate == null || !sameHead(left.heads().get(i), candidate)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     private static String rootMessage(Throwable failure) {
         Throwable current = failure;
         while (current.getCause() != null) current = current.getCause();

headdb-core/src/test/java/com/bitworksmc/headdb/implementation/BaseHeadDatabaseTest.java

@@ -154,6 +154,24 @@ void publishedCollectionsCannotBeMutated() {
         assertThrows(UnsupportedOperationException.class, () -> database.getByTags("Fruit").clear());
     }
 
+    @Test
+    void unchangedRevisionlessSnapshotKeepsPublishedList() {
+        AtomicInteger requests = new AtomicInteger();
+        server.createContext("/heads", exchange -> {
+            requests.incrementAndGet();
+            respond(exchange, 200, HEADS_JSON);
+        });
+        BaseHeadDatabase database = database("/heads", Index.ID);
+
+        List<Head> initial = database.update().join();
+        List<Head> refreshed = database.update().join();
+
+        assertSame(initial, refreshed);
+        assertSame(initial, database.getHeads());
+        assertEquals(-1, database.getCatalogRevision());
+        assertEquals(2, requests.get());
+    }
+
     @Test
     void appliesRevisionChangesAndRestoresTheSavedCatalog() {
         AtomicInteger snapshotRequests = new AtomicInteger();

pom.xml

@@ -22,7 +22,10 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.release>21</maven.compiler.release>
-        <adventure.version>5.2.0</adventure.version>
+        <!-- Compile against the Adventure API supplied by the minimum supported
+             Paper release. Newer Adventure runtimes retain compatibility with
+             clients compiled against this API, while the reverse is not true. -->
+        <adventure.version>4.17.0</adventure.version>
         <annotations.version>26.1.0</annotations.version>
         <paper.minecraft.version>26.2</paper.minecraft.version>
         <paper.version>1.21-R0.1-SNAPSHOT</paper.version>