NFD

I'm not sure of the cause but it looks like there is an issue with something called in "Fib::removeNextHopFromAllEntries".

If you add these debug messages to the code:

void
Fib::removeNextHopFromAllEntries(shared_ptr<Face> face)
{
  for (NameTree::const_iterator it = m_nameTree.fullEnumerate(
       &predicate_NameTreeEntry_hasFibEntry); it != m_nameTree.end();) {
       shared_ptr<fib::Entry> entry = it->getFibEntry();

    ++it; // advance the iterator before `erase` invalidates it

    std::cout << "Before " << entry->getPrefix() << ": " << entry->getNextHops().size() << std::endl;
    entry->removeNextHop(face);
    std::cout << "After " << entry->getPrefix() << ": " << entry->getNextHops().size() << std::endl;

    if (!entry->hasNextHops()) {
      this->erase(*entry);
    }
  }

  std::cout << "After NextHop removal" << std::endl;
  for (NameTree::const_iterator it = m_nameTree.fullEnumerate(&predicate_NameTreeEntry_hasFibEntry);
       it != m_nameTree.end(); ++it) 
  {
    shared_ptr<fib::Entry> entry = it->getFibEntry();
    std::cout << entry->getPrefix() << ": " << entry->getNextHops().size() << std::endl;
  }
}

You get:

...
Before /localhost/app/%FD%04: 1
After /localhost/app/%FD%04: 0
Before /localhost/app/%FD%01%24: 1
After /localhost/app/%FD%01%24: 0
After NextHop removal
/localhost/app/%FD%CD: 1
/localhost/app/%FDc: 1
/localhost/app/%FDS: 1
/localhost/app/%FD%A9: 1
/localhost/app/%FD%01: 1
/localhost/app/%FD%1D: 1
/localhost/app/%FDH: 1
...

So, it looks like the nexthops are not being removed and an invalid face is assigned to them by the FaceTable:

void
FaceTable::remove(shared_ptr<Face> face)
{
  ...
  face->setId(INVALID_FACEID);
  ...
  m_forwarder.getFib().removeNextHopFromAllEntries(face);
}

Alex/Junxiao: who's the right person to fix this problem?

It's too early to talk about assignment. We need to know the cause of this problem before deciding who to assign.

Can whoever wrote the code mentioned in note 2 figure out the problem?