[C++] PollInfo crashes if given a nullptr FlightInfo

[lidavidm]

Describe the bug, including details regarding any error messages, version, and platform.

This should be perfectly acceptable.

Component(s)

C++

[kou]

Oh, sorry.

I found this:

diff --git a/cpp/src/arrow/flight/types.cc b/cpp/src/arrow/flight/types.cc
index 9da83fa8a1..1d43c41b69 100644
--- a/cpp/src/arrow/flight/types.cc
+++ b/cpp/src/arrow/flight/types.cc
@@ -373,7 +373,12 @@ arrow::Result<std::unique_ptr<PollInfo>> PollInfo::Deserialize(
 
 std::string PollInfo::ToString() const {
   std::stringstream ss;
-  ss << "<PollInfo info=" << info->ToString();
+  ss << "<PollInfo info=";
+  if (info) {
+    ss << info->ToString();
+  } else {
+    ss << "null";
+  }
   ss << " descriptor=";
   if (descriptor) {
     ss << descriptor->ToString();

Do you know more missing nullptr checks?

[lidavidm]

I think the one I ran into was during serialization or deserialization.

arrow/cpp/src/arrow/flight/serialization_internal.cc

Line 334 in 55afcf0

RETURN_NOT_OK(ToProto(*info.info, pb_info->mutable_info()));