SceneBroadcaster: Use double for state publish frequency instead of int

[Thodoris1999]

…

🦟 Bug fix

Fixes #1414

Summary

Changed the state_hertz publishing frequency data type from int to double. Previously, worlds with those params set between 0 and 1 would crash due to being rounded to 0 and state_hertz being inverted. Note that dynamic_pose_hertz still gets rounded down to 0 as it is represented as int in AdvertiseOptions, but does not cause a crash.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[chapulina]

Thanks for the PR, the fix works for me!

Would you be able to add a test to test/integration/scene_broadcaster_system.cc? It will be tricky to check for precise publish times since the plugin uses the system clock, so I think the test could at least check that there's no crash.

[Thodoris1999]

I am a little new to this, is there an example for a test for crashing?

[Thodoris1999]

I think I can make death tests to check for crashes, is it ok? I am asking because I have not seen it in any other one of gazebo's test suites.

[chapulina]

I think I can make death tests to check for crashes, is it ok? I am asking because I have not seen it in any other one of gazebo's test suites.

Oh I don't think we need to go that far. Just exercising that code path and having the test run successfully should be enough to make sure there's no crash. This way, if someone reverts the changes from this PR in the future, the test will crash and we'll notice the regression.

Thanks!

[Thodoris1999]

I added a test with a simple SDF string. It passes with the current fix but if ran before the patch it crashes with Floating point exception (core dumped) as expected.

[chapulina]

Thanks for iterating!