Created attachment 301299 [details] [review]
Allow overriding WM_CLASS from the command line

Even when the program itself calls gdk_set_program_class(). There's
currently no way for this function to be called without breaking gdk's
--class command line option, because you cannot call it before
gtk_init().

Who is using --class, and why ? I'm not sure we really want to fix it up - I'd rather deprecate it...

We have a lot of users that have custom desktop files for gnome terminal profiles. To make them appear as separate applications in the launcher and alt-tab dialog, they pass --class with some id.

This is not necessary with the newest versions of terminal anymore, because it has --app-id. We do want to keep backwards compatibility for a while though. We'll likely print a warning at some point to ease the transition.

When do you plan on deprecating --class?

(In reply to Lars Uebernickel from comment #3)
 
> When do you plan on deprecating --class?

Because commandline arguments for libraries are awkward, and almost all of them have environment variable alternatives.

(In reply to Matthias Clasen from comment #4)
> (In reply to Lars Uebernickel from comment #3)
>  
> > When do you plan on deprecating --class?
> 
> Because commandline arguments for libraries are awkward, and almost all of
> them have environment variable alternatives.

I asked "when".

I totally agree with your reasoning and only proposed this patch to keep backwards compatibility.

What do you think about making --class a no-op with a deprecation warning instead?

oh, missed the when. This cycle, I guess ?

I am ok with keeping them working in the meantime (until 4.0), but is this case here recent breakage ? Hasn't this always been the case ?

(In reply to Matthias Clasen from comment #6)
> oh, missed the when. This cycle, I guess ?
> 
> I am ok with keeping them working in the meantime (until 4.0), but is this
> case here recent breakage ? Hasn't this always been the case ?

Yes, this bug has always existed, but gnome-terminal hasn't called gdk_set_program_class() forever. We just updated to a recent version of it in Ubuntu, which is why we noticed.

I guess not many other applications call that function and not many users need --class.

(In reply to Matthias Clasen from comment #6)
> […]
> I am ok with keeping them working in the meantime (until 4.0), but is this
> case here recent breakage ? Hasn't this always been the case ?

If you're okay, can we take a patch like this one then? With a deprecation warning, if you like. I'd like to keep cases like gnome-terminal working if possible.

Maybe that is a stupid question, but why can't you call gdk_set_program_class before gtk_init() ? Just us declaring such use illegal ?

We could just add a not to the docs that it is ok to do so, like we have for gdk_disable_multidevice right below it.

And with that it becomes a gnome-terminal problem instead of a gtk+ problem.

(In reply to Matthias Clasen from comment #9)
> Maybe that is a stupid question, but why can't you call
> gdk_set_program_class before gtk_init() ? Just us declaring such use illegal
> ?

I thought about that as well, but the global 'gdk_progclass' is set in gtk_init (through gdk_pre_parse_libgtk_only). Apparently it's done that way so that --name doesn't override it.

I have to admit that I am still a little confused why you are trying to fix a gnome-terminal change by applying a patch in GTK+. If gnome-terminal is wrong to set the class, then it should not do that... looking at gnome-terminal git, there has been quite a bit of back-and-forth there wrt to wm class...

(In reply to Matthias Clasen from comment #11)
> I have to admit that I am still a little confused why you are trying to fix
> a gnome-terminal change by applying a patch in GTK+. If gnome-terminal is
> wrong to set the class, then it should not do that... looking at
> gnome-terminal git, there has been quite a bit of back-and-forth there wrt
> to wm class...

Because it's a bug in gtk. An application cannot call gdk_set_program_class() without breaking --class. So effectively, it can't ever call it.

We only noticed this bug because gnome-terminal started calling this function.

Attachment 301299 [details] pushed as a8e5cac - Allow overriding WM_CLASS from the command line