Reduce memory used by DDS client

[srmainwaring]

Remove unused TFMessage variable and reduce size of pre-allocate arrays in XRCE DDS message types.

Dependencies

Requires upstream change:

• Allow for user-defined array sizes eProsima/Micro-XRCE-DDS-Gen#68
• Update IDL-Parser eProsima/Micro-XRCE-DDS-Gen#74

Which are applied to the ArduPilot forks in:

• Support user defined preallocated array sizes  OMG-IDL-Parser#1
• Update IDL-Parser Micro-XRCE-DDS-Gen#2

Tasks

• Require a submodule update in this PR before merging.

Testing

Before

AP: DDS: ********** DDS message sizes **********
AP: DDS: ardupilot_msgs_srv_ArmMotors_Request:   1
AP: DDS: ardupilot_msgs_srv_ArmMotors_Response:  1
AP: DDS: builtin_interfaces_msg_Time:            8
AP: DDS: geographic_msgs_msg_GeoPoseStamped:     320
AP: DDS: geometry_msgs_msg_PoseStamped:          320
AP: DDS: geometry_msgs_msg_TwistStamped:         312
AP: DDS: sensor_msgs_msg_Joy:                    1072
AP: DDS: sensor_msgs_msg_NavSatFix:              376
AP: DDS: rosgraph_msgs_msg_Clock:                8
AP: DDS: tf2_msgs_msg_TFMessage:                 57608
AP: DDS: AP_DDS_Client:                          119768
AP: DDS: ********** DDS message sizes **********

After

AP: DDS: ********** DDS message sizes **********
AP: DDS: ardupilot_msgs_srv_ArmMotors_Request:   1
AP: DDS: ardupilot_msgs_srv_ArmMotors_Response:  1
AP: DDS: builtin_interfaces_msg_Time:            8
AP: DDS: geographic_msgs_msg_GeoPoseStamped:     320
AP: DDS: geometry_msgs_msg_PoseStamped:          320
AP: DDS: geometry_msgs_msg_TwistStamped:         312
AP: DDS: sensor_msgs_msg_BatteryState:           920
AP: DDS: sensor_msgs_msg_Joy:                    336
AP: DDS: sensor_msgs_msg_NavSatFix:              376
AP: DDS: rosgraph_msgs_msg_Clock:                8
AP: DDS: tf2_msgs_msg_TFMessage:                 4616
AP: DDS: AP_DDS_Client:                          9168
AP: DDS: ********** DDS message sizes **********

Run on SITL and on MatekH743 / plane.

[Ryanf55]

LGTM. Hopefully upstream merges the dependencies soon with our endorsement. Once that's done, this can go in.

[tridge]

Nice memory reduction!

[Ryanf55]

Can you squash the commits together? Each one looks good.

[srmainwaring]

Can you squash the commits together? Each one looks good.

Could do, though I kept them separate on purpose to make it clear what was changing: 1. removal of unused variable, 2. change in upstream dep, and 3. an unrelated bug fix.

[Ryanf55]

Can you squash the commits together? Each one looks good.

Could do, though I kept them separate on purpose to make it clear what was changing: 1. removal of unused variable, 2. change in upstream dep, and 3. an unrelated bug fix.
Alright, I'll request a merge in dev call as-is.

[Ryanf55]

We agreed in dev call a final test on hardware would be a good idea before merging. The plan is this can be backported to 4.5 with the testing complete. I'll test on Pixhawk 6X with serial.

[srmainwaring]

I'll test on Pixhawk 6X with serial.

Ok. I'm running on a MatekH743-WING using MatekH743-bdshot with DDS and PPP enabled and it's working well. Will be good to have coverage of other boards.

[Ryanf55]

I think the testing Rhys has done is sufficient. Are we ok to merge this so it can be part of 4.5?