throw_bad_optional_access in HttpConnectionManager

[alyssawilk]

As reported by @tonya11en

At Lyft, we've observed an Envoy crash with the following stack trace on build 6d9de10:

Backtrace:
#0 0x00007f05ab87ac37 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#0 0x00007f05ab87ac37 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007f05ab87e028 in __GI_abort () at abort.c:89
#2 0x0000000000bd711d in __gnu_cxx::__verbose_terminate_handler() ()
#3 0x0000000000ba3df6 in __cxxabiv1::__terminate(void ()()) ()
#4 0x0000000000ba3e31 in std::terminate() ()
#5 0x0000000000ba52a8 in __cxa_throw ()
#6 0x0000000000b80ea7 in absl::optional_internal::throw_bad_optional_access() ()
#7 0x00000000007100af in value (this=) at external/com_google_absl/absl/types/optional.h:844
#8 Envoy::Http::ConnectionManagerImpl::ActiveStream::createFilterChain (this=this@entry=0x3cbd2000) at external/envoy/source/common/http/conn_manager_impl.cc:1408
#9 0x000000000071559b in createFilterChain (this=0x3cbd2000) at external/envoy/source/common/http/conn_manager_impl.cc:1001
#10 Envoy::Http::ConnectionManagerImpl::ActiveStream::sendLocalReply(bool, Envoy::Http::Code, std::string const&, std::function<void (Envoy::Http::HeaderMap&)> const&, bool, absl::optionalEnvoy::Grpc::Status::GrpcStatus) (this=this@entry=0x3cbd2000, is_grpc_request=is_grpc_request@entry=false, code=code@entry=Envoy::Http::UpgradeRequired, body=..., modify_headers=..., is_head_request=is_head_request@entry=false, grpc_status=...) at external/envoy/source/common/http/conn_manager_impl.cc:1002
#11 0x000000000071ab1b in Envoy::Http::ConnectionManagerImpl::ActiveStream::decodeHeaders(std::unique_ptr<Envoy::Http::HeaderMap, std::default_deleteEnvoy::Http::HeaderMap >&&, bool) (this=0x3cbd2000, headers=, end_stream=true) at external/envoy/source/common/http/conn_manager_impl.cc:573
#12 0x000000000074154a in Envoy::Http::Http1::ServerConnectionImpl::onMessageComplete (this=0x4398b40) at external/envoy/source/common/http/http1/codec_impl.cc:623
#13 0x0000000000744afc in Envoy::Http::Http1::ConnectionImpl::onMessageCompleteBase (this=0x4398b48) at external/envoy/source/common/http/http1/codec_impl.cc:442
#14 0x0000000000744bbd in operator() (__closure=0x0, parser=) at external/envoy/source/common/http/http1/codec_impl.cc:294
#15 Envoy::Http::Http1::ConnectionImpl::<lambda(http_parser)>::_FUN(http_parser ) () at external/envoy/source/common/http/http1/codec_impl.cc:296
#16 0x0000000000747a9f in http_parser_execute ()
#17 0x00000000007427c2 in Envoy::Http::Http1::ConnectionImpl::dispatchSlice (this=this@entry=0x4398b48, slice=, len=) at external/envoy/source/common/http/http1/codec_impl.cc:378
#18 0x00000000007445b3 in Envoy::Http::Http1::ConnectionImpl::dispatch (this=0x4398b48, data=...) at external/envoy/source/common/http/http1/codec_impl.cc:363
#19 0x0000000000717988 in Envoy::Http::ConnectionManagerImpl::onData (this=0x156381c0, data=...) at external/envoy/source/common/http/conn_manager_impl.cc:230
#20 0x00000000005f30e7 in Envoy::Network::FilterManagerImpl::onContinueReading (this=this@entry=0x29ad8018, filter=filter@entry=0x0) at external/envoy/source/common/network/filter_manager_impl.cc:60
#21 0x00000000005f31bc in Envoy::Network::FilterManagerImpl::onRead (this=this@entry=0x29ad8018) at external/envoy/source/common/network/filter_manager_impl.cc:70
#22 0x00000000005f041f in onRead (read_buffer_size=205, this=0x29ad8000) at external/envoy/source/common/network/connection_impl.cc:263
#23 Envoy::Network::ConnectionImpl::onReadReady (this=this@entry=0x29ad8000) at external/envoy/source/common/network/connection_impl.cc:496
#24 0x00000000005f0c6e in Envoy::Network::ConnectionImpl::onFileEvent (this=0x29ad8000, events=3) at external/envoy/source/common/network/connection_impl.cc:472
#25 0x00000000005ea7f8 in operator() (__args#0=3, this=) at /usr/include/c++/5/functional:2267
#26 operator() (__closure=0x0, arg=, what=) at external/envoy/source/common/event/file_event_impl.cc:60
#27 Envoy::Event::FileEventImpl::<lambda(int, short int, void)>::_FUN(int, short, void ) () at external/envoy/source/common/event/file_event_impl.cc:61
#28 0x00000000008b9cef in event_persist_closure (ev=, base=0x2456dc0) at ../event.c:1580
#29 event_process_active_single_queue (base=base@entry=0x2456dc0, max_to_process=max_to_process@entry=2147483647, endtime=endtime@entry=0x0, activeq=) at ../event.c:1639
#30 0x00000000008ba41f in event_process_active (base=base@entry=0x2456dc0) at ../event.c:1738
#31 0x00000000008bd178 in event_base_loop (base=0x2456dc0, flags=) at ../event.c:1961
#32 0x00000000005e66b6 in Envoy::Server::WorkerImpl::threadRoutine (this=0x2edecc0, guard_dog=...) at external/envoy/source/server/worker_impl.cc:101
#33 0x00000000008cabe5 in Envoy::Thread::ThreadImpl::ThreadImpl(std::function<void ()>)::{lambda(void)#1}::_FUN(void*) () at /usr/include/c++/5/functional:2267
#34 0x00007f05abf1b184 in start_thread (arg=0x7f05a8c79700) at pthread_create.c:312
#35 0x00007f05ab94203d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
This is due to the usage of std:optional::value() to check whether an optional variable has a value instead of std::optional::has_value(). value() throws an exception if has_value() would return false, so I suspect the intention is what can be found in this PR.

Please let me know if I'm misunderstanding something.

Risk Level:
Low

Testing:
Existing UTs