[fix][ml] Fix getNumberOfEntries may point to deleted ledger (apache#24852)

(cherry picked from commit a85a064)

Author: Technoboy-

managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java

@@ -3716,11 +3716,17 @@ public long getNumberOfEntries(Range<Position> range) {
         boolean toIncluded = range.upperBoundType() == BoundType.CLOSED;
 
         if (fromPosition.getLedgerId() == toPosition.getLedgerId()) {
-            // If the 2 positions are in the same ledger
-            long count = toPosition.getEntryId() - fromPosition.getEntryId() - 1;
-            count += fromIncluded ? 1 : 0;
-            count += toIncluded ? 1 : 0;
-            return count;
+            LedgerInfo li = ledgers.get(toPosition.getLedgerId());
+            if (li != null) {
+                // If the 2 positions are in the same ledger
+                long count = toPosition.getEntryId() - fromPosition.getEntryId() - 1;
+                count += fromIncluded ? 1 : 0;
+                count += toIncluded ? 1 : 0;
+                return count;
+            } else {
+                // if the ledgerId is not in the ledgers, it means it has been deleted
+                return 0;
+            }
         } else {
             long count = 0;
             // If the from & to are pointing to different ledgers, then we need to :

managed-ledger/src/test/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerTest.java

@@ -42,6 +42,7 @@
 import static org.testng.Assert.assertSame;
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
+import com.google.common.collect.Range;
 import com.google.common.collect.Sets;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
@@ -2667,6 +2668,37 @@ public void testGetNumberOfEntriesInStorage() throws Exception {
         assertEquals(length, numberOfEntries);
     }
 
+    @Test
+    public void testGetNumberOfEntries() throws Exception {
+        ManagedLedgerConfig managedLedgerConfig = new ManagedLedgerConfig();
+        initManagedLedgerConfig(managedLedgerConfig);
+        managedLedgerConfig.setMaxEntriesPerLedger(5);
+        ManagedLedgerImpl managedLedger =
+                (ManagedLedgerImpl) factory.open("testGetNumberOfEntries", managedLedgerConfig);
+        // open cursor to prevent ledger to be deleted when ledger rollover
+        ManagedCursorImpl managedCursor = (ManagedCursorImpl) managedLedger.openCursor("cursor");
+        int numberOfEntries = 10;
+        List<Position> positions = new ArrayList<>(numberOfEntries);
+        for (int i = 0; i < numberOfEntries; i++) {
+            positions.add(managedLedger.addEntry(("entry-" + i).getBytes(Encoding)));
+        }
+        Position mdPos = positions.get(numberOfEntries - 1);
+        Position rdPos = PositionFactory.create(mdPos.getLedgerId(), mdPos.getEntryId() + 1);
+        managedCursor.delete(positions);
+        // trigger ledger rollover and wait for the new ledger created
+        Awaitility.await().untilAsserted(() -> {
+            assertEquals("LedgerOpened", WhiteboxImpl.getInternalState(managedLedger, "state").toString());
+        });
+        managedLedger.rollCurrentLedgerIfFull();
+        Awaitility.await().untilAsserted(() -> {
+            assertEquals(managedLedger.getLedgersInfo().size(), 1);
+            assertEquals(managedLedger.getState(), ManagedLedgerImpl.State.LedgerOpened);
+        });
+
+        long length = managedLedger.getNumberOfEntries(Range.closed(mdPos, rdPos));
+        assertEquals(length, 0);
+    }
+
     @Test
     public void testEstimatedBacklogSize() throws Exception {
         ManagedLedgerImpl ledger = (ManagedLedgerImpl) factory.open("testEstimatedBacklogSize");

pulsar-broker/src/test/java/org/apache/pulsar/compaction/CompactionTest.java

@@ -2297,7 +2297,7 @@ public void testAcknowledgeWithReconnection() throws Exception {
 
         Awaitility.await().untilAsserted(() ->
                 assertEquals(admin.topics().getStats(topicName, true).getSubscriptions().get(subName).getMsgBacklog(),
-                        5));
+                        0));
 
         // Make consumer reconnect to broker
         admin.topics().unload(topicName);