INTEGRATION_thruster has undefined behavior potentially causing test flakiness

[azeey]

Environment

• OS Version: Ubuntu 22.04
• Source or binary build? gz-sim7, 926923f

Description

• Expected behavior: Code has no undefined behaviors
• Actual behavior: std::vector::back is potentially called on an empty vector in multiple places. This is regarded as undefined behavior. For example:
  

  gz-sim/test/integration/thruster.cc

  Lines 335 to 340 in 926923f

  	modelPoses.clear();
  	propellerAngVels.clear();
  	propellerLinVels.clear();
  	// Make sure that when the deadband is disabled
  	// commands below the deadband should create a movement
  	auto latest_pose = modelPoses.back();

The vector modelPoses is cleared followed by auto latest_pose = modelPoses.back();

[GauravKumar9920]

can I work on this issue ?

[azeey]

Yes, please!

[GauravKumar9920]

hii, upon running the code check I found that this issue is persistent among many other similar files, like detachable_joint.cc, WindEffects.cc and many others, shall I fix most of them or just this one(thruster.cc) ?

[azeey]

Hi @GauravKumar9920, this issue is not about code style, but that accessing std::vector::back on an empty vector could cause a crash.