feat(autoware_behavior_path_side_shift_module): accept service inputs and add publisher to inform the current shift length

[TaikiYamada4]

Description

The side_shift module of the autoware_behavior_path_planner is somewhat a special module that is outside the frame of Dynamic Driving Tasks (DDT) because this module is aimed to modify the path laterally by a human hand.

Currently this feature obtains its shift length from a topic, however this will not tell the operator to know whether the requested shift_length is successfully received or not. Hence, this PR adds a new service to autoware_behavior_path_side_shift_module.

In addition the newly implemented service not only accepts direct shift length, but also adds a new shift mode that can send whether to go left or right. If this shift mode is selected the vehicle will shift its path with the shift length stated in the unit_shift_amount parameter. This unit shift will be accumulated as the shift request with the same direction has come.

Related links

• (autoware_launch) feat(autoware_behavior_path_side_shift_module): add parameters of limitations to the side shift autoware_launch#1800
• (tier4_autoware_msgs) feat: add SetLateralOffset service for side shift tier4/tier4_autoware_msgs#210

How was this PR tested?

• Tested that colcon test passes.
• Tested that the expected behavior is shown. (Look the video below)

side_shift_service-2026-04-06_11.01.08.mp4

Time	What is happening
0:00 - 0:13	The publisher constantly publishing the current lateral offset
0:14 - 0:19	Called the service in RAW_VALUE mode with 1.0 meter
0:20 - 0:31	Called the service in RAW_VALUE mode with -1.0 meter
0:32 - 0:40	Called the service in DIRECTION mode and select RESET(=0)
0:41 - 0:49	Called the service in DIRECTION mode and select LEFT(=1) several times. This shifts the path 0.1 meter each
0:50 - 0:52	RESET again
0:53 - 1:02	Called the service in DIRECTION mode and select RIGHT(=2) several times. This shifts the path 0.1 meter each
1:02 - 1:05	RESET again
1:06 - 1:15	Called the service in RAW_VALUE mode with 3.0 meters but the request declined since it exceeds threshold.

Notes for reviewers

I've moved the lateral_offset subscriber to the side_shift module to

• Handle the requested_lateral_offset_ from both topic and service correctly
• Try not to edit the planner_data_ from the module side
• In the name of modularity

Therefore, the lateral_offset field is removed from the planner_data_.

Besides, the current CI doesn't pass because the srv type must be merged first

• feat: add SetLateralOffset service for side shift tier4/tier4_autoware_msgs#210

Interface changes

Topic changes

Additions and removals

Change type	Topic Type	Topic Name	Message Type	Description
Added	Srv	~/set_lateral_offset	tier4_planning_msgs/SetLateralOffset	Set the lateral offset, or select LEFT, RIGHT, RESET to shift. See for further explanation.
Added	Pub	~/output/lateral_offset	tier4_planning_msgs/LateralOffset	The current lateral_offset (in meters)

ROS Parameter Changes

Additions and removals

Change type	Parameter Name	Type	Default Value	Description
Added	max_shift_magnitude	double	1.0 [m]	Maximum shift length the side_shift module can perform for safety reasons
Added	min_shift_gap	double	0.001 [m]	Minimum gap that the previous lateral offset and the current lateral offset can have in order not to have a very small shift path
Added	unit_shift_amount	double	0.1 [m]	The shift length once a LEFT or RIGHT command is requested from the set_lateral_offset service.

Effects on system behavior

1. The autoware_behavior_path_side_shift_module accepts ROS 2 service inputs
2. The side shift module will not shift the path more than max_shift_magnitude meters

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