Don't fail silently when trying to load a world without -f

[osrf-migration]

Original report (archived issue) by Michael Grey (Bitbucket: mxgrey, GitHub: mxgrey).

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Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Checked the Q&A board for common solutions: http://answers.gazebosim.org
  • Checked that your issue isn't already filed.
  • Checked that there is not already an Ignition package that provides the described functionality: https://ignitionrobotics.org/libs

Description

Using all the latest ignition branches, nothing seems to render when I try to run a world in ign-gazebo. I haven't tried to run a full ign-gazebo pipeline in a while, so it's hard to say how long this has been going on, but it was working fine as recently as mid-January.

Steps to Reproduce

For me this happens when trying to run any world using ign-gazebo. E.g. from the ign-gazebo root directory:

$ ign-gazebo -v 4 test/worlds/mesh.sdf

I get this:

And the following prints to the terminal:

[Msg] Ignition Gazebo        v0.1.0~pre1
[Msg] Ignition Gazebo GUI    v0.1.0~pre1
[Msg] Ignition Gazebo Server v0.1.0~pre1
[Dbg] [EntityComponentManager.cc:502] Register new component type 515269944612530032.
[Dbg] [EntityComponentManager.cc:502] Register new component type 17314316377527280772.
[Dbg] [EntityComponentManager.cc:502] Register new component type 17116448167660919050.
[Dbg] [EntityComponentManager.cc:502] Register new component type 5229559171816935132.
[Dbg] [EntityComponentManager.cc:502] Register new component type 4730666468951701659.
[Dbg] [EntityComponentManager.cc:502] Register new component type 13669903581159109821.
[Dbg] [Application.cc:87] Initializing application.
[GUI] [Dbg] [Application.cc:395] Create main window
[Msg] Serving scene information on [/world/default/scene/info]
[Msg] Serving graph information on [/world/default/scene/graph]
[Msg] Serving scene information on [/world/default/scene/info]
[Msg] Publishing entity deletions on [/world/default/scene/deletion]
[Msg] Publishing pose messages on [/world/default/pose/info]
[Msg] Serving GUI information on [/world/default/gui/info]
[Msg] World [default] initialized with [default_physics] physics profile.
[GUI] [Msg] Loading config [/home/grey/projects/gz11/install/ignition-gazebo/share/ignition/gazebo0/gui/gui.config]
[GUI] [Dbg] [Application.cc:267] Loading window config
[GUI] [Dbg] [Application.cc:409] Applying config
[GUI] [Dbg] [gui_main.cc:179] Requesting list of world names...
[GUI] [Dbg] [gui_main.cc:200] Requesting GUI from [/world/default/gui/info]...
[GUI] [Msg] Loading plugin [Scene3D]
[GUI] [Msg] Added plugin [3D View] to main window
[GUI] [Msg] Loading plugin [WorldControl]
[GUI] [Msg] Added plugin [World control] to main window
[GUI] [Msg] Loading plugin [WorldStats]
[GUI] [Msg] Added plugin [World stats] to main window
[GUI] [Msg] Loading plugin [ignition-rendering1-ogre]
[GUI] [Dbg] [Scene3D.cc:883] Create scene [scene]
Topic [] is not valid.
[GUI] [Err] [Scene3D.cc:416] Error subscribing to deletion topic: 
Topic [] is not valid.
[GUI] [Err] [Scene3D.cc:421] Error subscribing to scene topic: 

And then during teardown:

[GUI] [Dbg] [gui_main.cc:230] Shutting down ign-gazebo-gui
[GUI] [Dbg] [Application.cc:130] Terminating application.
[GUI] [Dbg] [Scene3D.cc:933] Destroy scene [scene]
[Dbg] [SignalHandler.cc:141] Received signal[2].
[Dbg] [SignalHandler.cc:141] Received signal[2].
[Dbg] [ServerPrivate.cc:55] Server received signal[2]
[Dbg] [server_main.cc:167] Shutting down ign-gazebo-server
[Dbg] [main.cc:276] Shutting down ign-gazebo

Versions

I'm using all the gz11 branches, or default for repos that don't have a gz11 branch (but the ign-plugin1 branch for ign-plugin).

Additional Information

I'm using Ubuntu 18.04 with an AMD graphics card. I've found AMD graphics cards to be a bit unreliable with OGRE, so maybe that's the culprit? But this issue only emerged recently.

Also worth noting, all of the tests pass on my machine for ign-gazebo, ign-gui, and ign-rendering.

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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This happens to me all the time, you forgot the -f before the file path.

I think we have to handle this case better.

[osrf-migration]

Original comment by Michael Grey (Bitbucket: mxgrey, GitHub: mxgrey).

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Thanks, that was the issue! 😅

Is there a particular reason we don't support the world file as a positional argument like the old Gazebo? If we want to commit to no longer supporting that, then we should at least update the help text, which currently says the command signature is:

`ign-gazebo` [options] <world_file>

which implies that you're required to pass a world file at the end as a positional argument (<argument_name> in angle brackets at the end of the command signature usually implies a mandatory positional argument, so we should use brackets [argument_name] for optional arguments).

Additionally, we could print console warnings if users pass in unexpected arguments or neglect to load a world at startup.

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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+1 to all your suggestions

[osrf-migration]

Original comment by Michael Grey (Bitbucket: mxgrey, GitHub: mxgrey).

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Do you think it would be better to make the world_file argument an optional positional argument to match previous Gazebos, or keep it as a flagged option like it currently is?

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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I have no preference, but if I remember correctly, @nkoenig had a reason to add a flag initially.

[osrf-migration]

Original comment by Michael Grey (Bitbucket: mxgrey, GitHub: mxgrey).

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I feel like an optional positional argument makes the most sense since it matches typical Unix conventions the closest, but I'll hold off on submitting any changes until we hear from Nate.

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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• changed title from "Nothing shows up in the rendering?" to "Don't fail silently when trying to load a world without -f"

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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See pull request #298

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

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• changed state from "new" to "resolved"