refactor(lane_change): refactor getLaneChangePaths function

[mkquda]

Description

The function getLaneChangePaths in LC module is the main part of LC code and is responsible for sampling different candidate paths and verifying the validity and safety of the candidate path. However the function is very big and complex, which makes it difficult to understand and modify.

This PR aims to refactor the getLaneChangePaths function to improve code readability and granularity and reduce its complexity.

Changes

• Add struct PhaseMetrics to group relevant measurements (duration, length, velocity, lon. acc, lat. acc) for LC phases
• Add function calc_prepare_phase_metrics to compute and return a list of sampled prepare phase metrics
• Add function calc_shift_phase_metrics to compute and return a list of sampled lane changing phase metrics
• Remove the necessity of computing target segment, and use reference path from target lane directly instead
• Add function getCandidatePath to process LC info and construct the cadidate path
• Add function checkCandidatePathSafety to verify LC candidate path

Flowchart of getLaneChangePaths function after refactoring

Related links

None.

How was this PR tested?

1. Build complete
2. PSIM
3. Internal TIER IV evaluator

Notes for reviewers

None.

Interface changes

None.

Effects on system behavior

None.

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 0.48309% with 206 lines in your changes missing coverage. Please review.

Project coverage is 28.45%. Comparing base (d25e9a1) to head (e89ef23).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...are_behavior_path_lane_change_module/src/scene.cpp	0.00%	116 Missing ⚠️
..._path_lane_change_module/src/utils/calculation.cpp	0.00%	55 Missing ⚠️
...ior_path_lane_change_module/utils/data_structs.hpp	5.55%	17 Missing ⚠️
...nning/autoware_route_handler/src/route_handler.cpp	0.00%	11 Missing ⚠️
...havior_path_lane_change_module/src/utils/utils.cpp	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8909      +/-   ##
==========================================
- Coverage   28.47%   28.45%   -0.02%     
==========================================
  Files        1314     1318       +4     
  Lines       98279    98318      +39     
  Branches    39961    39969       +8     
==========================================
- Hits        27985    27980       -5     
- Misses      70166    70209      +43     
- Partials      128      129       +1     

Flag	Coverage Δ		*Carryforward flag
differential	28.04% <0.48%> (?)
total	28.52% <ø> (+0.05%)	⬆️	Carriedforward from fa5a5fe

*This pull request uses carry forward flags. Click here to find out more.

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[maxime-clem]

I only checked the code and it looks good.
The CI failure is caused by a random test failure so re-running it should fix the issue. (the random failure is supposed to be fixed by #8799 but I guess not).

[github-actions]

Documentation URL: https://autowarefoundation.github.io/autoware.universe/pr-8909/
Modified URLs:

• https://autowarefoundation.github.io/autoware.universe/pr-8909/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/

[zulfaqar-azmi-t4]

Nice. LGTM!