PositionImpl init throws NullPointerException

[laxpio]

Describe the bug
version 2.4.1

code path：
managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/PositionImpl.java

init function

public static PositionImpl get(PositionImpl other) {
        return new PositionImpl(other);
    }
public PositionImpl(PositionImpl other) {
        this.ledgerId = other.ledgerId;
        this.entryId = other.entryId;
    }

when the param "other" be Null Object, the process will throw NullPointerException.

[jiazhai]

@laxpio Thanks for reporting this. How about return a NULL when passed in NULL?

[laxpio]

the readPosition will be null when ledger list is null or can not find the nextValidPosition
the code as follow:
managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedCursorImpl.java

public void asyncReadEntries(final int numberOfEntriesToRead, final ReadEntriesCallback callback,
            final Object ctx) {
        checkArgument(numberOfEntriesToRead > 0);
        if (isClosed()) {
            callback.readEntriesFailed(new ManagedLedgerException("Cursor was already closed"), ctx);
            return;
        }

        PENDING_READ_OPS_UPDATER.incrementAndGet(this);
        OpReadEntry op = OpReadEntry.create(this, PositionImpl.get(readPosition), numberOfEntriesToRead, callback, ctx);
        ledger.asyncReadEntries(op);
    }

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

public static OpReadEntry create(ManagedCursorImpl cursor, PositionImpl readPositionRef, int count,
            ReadEntriesCallback callback, Object ctx) {
        OpReadEntry op = RECYCLER.get();
        op.readPosition = cursor.ledger.startReadOperationOnLedger(readPositionRef);
        op.cursor = cursor;
        op.count = count;
        op.callback = callback;
        op.entries = Lists.newArrayList();
        op.ctx = ctx;
        op.nextReadPosition = PositionImpl.get(op.readPosition);
        return op;
    }

[tisonkun]

Closed as stale. Please open a new issue if it's still relevant in maintained versions.

If we don't have a real-world issue on this NPE, I tend to close this kind of issue if there's no volunteer to improve.