Revert "[foxy backport] Ensure rviz_common::MessageFilterDisplay processes messages in the main thread (#620)"

[gbalke]

Reverts #765

See #782. This broke rviz pointcloud displays (and likely other displays dependent on this class). Locally reverted and tested (points are displayed properly).

[gbalke]

CI up to Rviz:

• Linux
• Linux-aarch64
• macOS
• Windows

[gbalke]

To note, #620 works as intended. Apparently the virtual/override removal was the culprit. The code works with them back in place. These two were expected to break ABI which is why they were removed.

diff --git a/rviz_common/include/rviz_common/message_filter_display.hpp b/rviz_common/include/rviz_common/message_filter_display.hpp
index 64d61970..bf46001d 100644
--- a/rviz_common/include/rviz_common/message_filter_display.hpp
+++ b/rviz_common/include/rviz_common/message_filter_display.hpp
@@ -187,7 +187,7 @@ protected:
     Q_EMIT typeErasedMessageTaken(std::static_pointer_cast<const void>(msg));
   }

-  void processTypeErasedMessage(std::shared_ptr<const void> type_erased_msg)
+  void processTypeErasedMessage(std::shared_ptr<const void> type_erased_msg) override
   {
     auto msg = std::static_pointer_cast<const MessageType>(type_erased_msg);

diff --git a/rviz_common/include/rviz_common/ros_topic_display.hpp b/rviz_common/include/rviz_common/ros_topic_display.hpp
index fdbce90b..15411a31 100644
--- a/rviz_common/include/rviz_common/ros_topic_display.hpp
+++ b/rviz_common/include/rviz_common/ros_topic_display.hpp
@@ -116,7 +116,7 @@ Q_SIGNALS:
   void typeErasedMessageTaken(std::shared_ptr<const void> type_erased_message);

 protected Q_SLOTS:
-  void processTypeErasedMessage(std::shared_ptr<const void> type_erased_message)
+  virtual void processTypeErasedMessage(std::shared_ptr<const void> type_erased_message)
   {
     (void)type_erased_message;
   }

[jacobperron]

@gbalke Could you try out https://github.com/ros2/rviz/tree/jacob/fix_782? I hope fixes the issue and remains ABI compatible.

[gbalke]

@gbalke Could you try out https://github.com/ros2/rviz/tree/jacob/fix_782? I hope fixes the issue and remains ABI compatible.

@jacobperron This isn't working. It immediately crashes on publish of a PointCloud2 message:

QObject::connect: No such signal rviz_common::_RosTopicDisplay::typeErasedMessageTaken(std::shared_ptr<const void>)
QObject::connect:  (sender name:   'PointCloud2')
QObject::connect:  (receiver name: 'PointCloud2')
rviz2: symbol lookup error: /home/ubuntu/dev/scratchwork/issue-782/new_ws/install/lib/librviz_default_plugins.so: undefined symbol: _ZN11rviz_common20MessageFilterDisplayIN11sensor_msgs3msg12PointCloud2_ISaIvEEEE22typeErasedMessageTakenESt10shared_ptrIKvE