ign -> gz Header Migration : ign-msgs

[methylDragon]

See gazebo-tooling/release-tools#711

Notes:

• proto message definitions for gz and ignition will be installed alongside each other, but ONLY THE gz proto messages will result in code generation for sources and headers.
• The entirety of the ignition headers are instantiated as redirection headers pointing to the gz version
• The gz headers use the ignition namespace, pending namespace migration

[codecov]

Codecov Report

Merging #249 (48a8297) into main (e61edda) will decrease coverage by 1.82%.
The diff coverage is n/a.

❗ Current head 48a8297 differs from pull request most recent head d512175. Consider uploading reports for the commit d512175 to get more accurate results

@@            Coverage Diff             @@
##             main     #249      +/-   ##
==========================================
- Coverage   15.90%   14.08%   -1.83%     
==========================================
  Files         382      764     +382     
  Lines       71409   142630   +71221     
==========================================
+ Hits        11361    20088    +8727     
- Misses      60048   122542   +62494     

Impacted Files	Coverage Δ
include/gz/msgs/boxgeom.pb.h	5.71% <0.00%> (ø)
include/gz/msgs/world_modify.pb.cc	14.17% <0.00%> (ø)
include/gz/msgs/laserscan.pb.cc	9.11% <0.00%> (ø)
include/gz/msgs/sonar.pb.h	0.00% <0.00%> (ø)
include/gz/msgs/tactile.pb.cc	14.17% <0.00%> (ø)
include/gz/msgs/imu_sensor.pb.cc	12.96% <0.00%> (ø)
include/gz/msgs/subscribe.pb.cc	13.86% <0.00%> (ø)
include/gz/msgs/uint64.pb.cc	19.23% <0.00%> (ø)
include/gz/msgs/cmd_vel2d.pb.cc	17.94% <0.00%> (ø)
include/gz/msgs/world_stats.pb.h	1.94% <0.00%> (ø)
... and 372 more

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[methylDragon]

All green!

[chapulina]

It looks like the import calls inside downstream messages are broken with this PR. I tried to compile gz-sim's main branch on top of this PR and it fails with:

/home/chapulina/dev_focal/ws_garden/build/ignition-gazebo7/src/msgs/peer_control.pb.cc:23:8: error: _PROTOBUF_INTERNAL_EXPORT_protobuf_ignit
ion_2fmsgs_2fheader_2eproto_ does not name a type; did you mean _PROTOBUF_INTERNAL_EXPORT_protobuf_gz_2fmsgs_2fheader_2eproto_?             
   23 | extern PROTOBUF_INTERNAL_EXPORT_protobuf_ignition_2fmsgs_2fheader_2eproto ::google::protobuf::internal::SCCInfo<2> scc_info_Header;       |        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                                           
      |        PROTOBUF_INTERNAL_EXPORT_protobuf_gz_2fmsgs_2fheader_2eproto
/home/chapulina/dev_focal/ws_garden/build/ignition-gazebo7/src/msgs/peer_control.pb.cc:50:51: error: _scc_info_Header_ is not a member of _p
rotobuf_ignition_2fmsgs_2fheader_2eproto_                                                                                                   
   50 |       &protobuf_ignition_2fmsgs_2fheader_2eproto::scc_info_Header.base,}};                                                                |                                                   ^~~~~~~~~~~~~~~                                       
/home/chapulina/dev_focal/ws_garden/build/ignition-gazebo7/src/msgs/peer_control.pb.cc: In function _void protobuf_peer_5fcontrol_2eproto::A
ddDescriptorsImpl()_:                                                                                                                       
/home/chapulina/dev_focal/ws_garden/build/ignition-gazebo7/src/msgs/peer_control.pb.cc:105:48: error: _AddDescriptors_ is not a member of _p
rotobuf_ignition_2fmsgs_2fheader_2eproto_                                                                                                   
  105 |   ::protobuf_ignition_2fmsgs_2fheader_2eproto::AddDescriptors();                                                                    
      |                                                ^~~~~~~~~~~~~~ 

I believe that's coming from here.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@e61edda). Click here to learn what that means.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #249   +/-   ##
=======================================
  Coverage        ?   15.90%           
=======================================
  Files           ?      382           
  Lines           ?    71409           
  Branches        ?        0           
=======================================
  Hits            ?    11361           
  Misses          ?    60048           
  Partials        ?        0           

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[methylDragon]

Going with the deferred hard-tock option (B) with gz headers directing to ignition for now, and ignition being the "canonical" message definitions at the moment.

Gazebo builds.

Once we're ready, and namespaces have been migrated, we will then move forward with hard-tocking every message (and message header) to gz.

[chapulina]

LGTM, this shouldn't break any downstream libraries as it is.

We'll come back for the hard tock later. I'd like to at least make the C++ redirection headers work, because that's what most people are using.

The proto namespaces are only used by people creating custom messages or doing some other kind of advanced usage of the messages. Ideally we'd tick-tick the change, but it's proving difficult, so I think those advanced users will have to deal with a hard-tock. Fortunately, the migration only requires a quick search-and-replace on their end.

[chapulina]

🤔

[methylDragon]

Fixed! 684b316

I'll merge once CI is green 🙌