Support 'has' functionality in particle Emitter.

[nkoenig]

Signed-off-by: Nate Koenig [email protected]

🦟 Bug fix

Summary

The particle emitter message used plain data types. This prevents an Ignition system from knowing if a value has been set. Since we are using the emitter message as the Component in Ignition, we need this information.

I'm changing the message types. Since this message was just introduced the impact should be minimal.

Required by: gazebosim/gz-sim#651

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)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge

[codecov]

Codecov Report

Merging #137 (528b937) into ign-msgs6 (185d467) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           ign-msgs6     #137   +/-   ##
==========================================
  Coverage      84.59%   84.59%           
==========================================
  Files              7        7           
  Lines            818      818           
==========================================
  Hits             692      692           
  Misses           126      126           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 185d467...528b937. Read the comment docs.

[chapulina]

This breaks API and can't go into a stable release. It needs to be retargeted to main, and even then, I think we should consider a tick-tock strategy.

[nkoenig]

This breaks API and can't go into a stable release. It needs to be retargeted to main, and even then, I think we should consider a tick-tock strategy.

The particle emitter was added in the last minor release. I'm making this change in a subsequent minor release. The impact is minimal and is needed by subt.

[chapulina]

Ok, let's make this exception since there are probably no users of particles yet and the release is still fresh. In the future, we should consider making pre-releases for new features that are still under development.

We need to time well the next ign-msgs6and ign-gazebo4 releases so that no users are left in a broken state, and it's very important to set minimum required versions on both ign-gazebo and ign-gazebo4-release.

Can you add a note about the ABI break to the migration guide?

[nkoenig]

Can you add a note about the ABI break to the migration guide?

Added in ef3e3f4