Crash caused by service "/world/default/enable_collision"

[gzfuzz]

Environment

• OS Version: Ubuntu 22.04
• Source or binary build?
  source build
  gz-sim version: 5641ef2
  built with
  gcc version: 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
  build options: -DCMAKE_BUILD_TYPE=Coverage

Description

• Expected behavior: Gazebo doesn't crash
• Actual behavior: Gazebo crashes

Steps to reproduce:

1. run gz sim with an empty world
2. gz service --timeout 10000 -s /world/default/enable_collision --reptype gz.msgs.Boolean --reqtype gz.msgs.Entity --req 'type: COLLISION'

Output

a.log

[azeey]

Thanks for reporting this. It looks like the code doesn't check if the provided entity is valid

gz-sim/src/systems/user_commands/UserCommands.cc

Lines 585 to 588 in c4b55bd

	auto *linkEntity = ecm->Component<components::ParentEntity>(_collision);
	auto allLinkSensors =
	ecm->EntitiesByComponents(components::Sensor(),
	components::ParentEntity(*linkEntity));

i.e., we need to check if linkEntity is nullptr there. Would you be able to create a PR with that change?

[akky20]

@azeey I have reaised a PR for this issue , please have a look into it..