Re: Reinstate support for OS X versions older than 10.9

[Ryan Schmidt <gtk ryandesign com>]

On Sep 23, 2015, at 1:04 AM, Nirbheek Chauhan wrote:

> Just to add to this, GStreamer 1.x currently supports OS X 10.8, so it
> would be great if GLib continued to support at least that. Support for
> older versions should, I suppose, be welcome as well since Ryan says
> he's willing to maintain it. :)

To clarify what I mean when I say I am the maintainer of glib2 in MacPorts: that title means that I have 
declared myself responsible for keeping glib2 in MacPorts updated and working, and will try to report issues 
to the developers for them to resolve. It doesn't mean that I know anything about the glib codebase, nor that 
I am even a competent C programmer.


On Sep 23, 2015, at 5:14 AM, Bastien Nocera wrote:

> I don't think that making new APIs do nothing, or ABI changing between
> OSX versions is a good idea.

I'm not familiar with what constitutes API or ABI in the context of glib, but the fact is that prior to 
2.46.0, GNotification support did not exist in glib on OS X, therefore all the existing software that 
successfully used glib on OS X didn't care about that missing support.

> You might want to work on adding support
> for another notification sub-system (I don't think that OSX had one
> builtin before 10.9, or without the needed feature), such as Growl.
> Then make GNotification choose which one to use at run-time.


As I understand it, that would mean that the build system would have to be modified to detect if Notification 
Center support exists at build time (i.e. if the OS X 10.9 SDK or later is being used), and would weak-link 
to it if found. The code would check at runtime if the symbol exists (i.e. if we are running on OS X 10.9 or 
later), and if so it would use Notification Center. I would be in favor of such changes.

I also have no objection to Growl support being added as an alternative. But since Growl is a third-party 
product, I predict that most users do not have it installed. So glib would need to accommodate the case of 
neither Growl nor Notification Center existing.


On Sep 23, 2015, at 5:47 AM, Emmanuele Bassi wrote:

> For instance, supporting MacOS 10.8 would give us about 80% of the
> installed users base for MacOS; going back to 10.7 we'd reach about
> 90% — and after that we enter the land of diminishing returns. Those
> figures are not going to get better in the future, either. Strict
> support cut offs and free updates push OS upgrades forward. Also, I'd
> like to point out that the oldest Apple-supported OS version is 10.8
> (at least for security updates).

Citing percentages ignores the fact that there are real actual users on OS X 10.8 and earlier currently using 
software that requires glib, and that these real actual users will not be able to use the current version of 
glib anymore. This leaves the distributors of that software (which might be a package management system like 
MacPorts, or it might be the developers of the software themselves, in case they distribute their own binary 
packages) to decide between staying with an older version of glib (which may contain bugs that have already 
been fixed in newer versions of glib), or else upgrading glib, thus alienating the users of older systems who 
then have to use older versions of the software which may itself have bugs already fixed in newer versions.


> The API for sending notifications via GApplication cannot
> programmatically fail — but the documentation helpfully says:
>
>    There is no guarantee that the notification is displayed
> immediately, or even at all.
>
> Which at least gives us some leeway in not supporting platforms that
> do not have system notification API.

Sounds great: if Notification Center support is not available at runtime, then simply do nothing.


On Sep 23, 2015, at 9:53 AM, Nicolas Dufresne wrote:

> That I agree. If the supporting companies for these proprietary OS drop
> support for stuff removing and remove it devkits while making older
> devkit no longer available, it will be hard for us to keep up (and a
> waste of our time most likely).

I'm not certain what you mean. Certainly, Apple stops releasing new versions of Xcode for old OS X versions 
at some point. But there is nothing preventing a developer from setting up an older Mac with an old version 
of OS X and downloading the corresponding old version of Xcode from the Apple developer web site.

You don't even necessarily need an old Mac: you can use Parallels or VMware Fusion or Virtual Box on a new 
Mac to run a virtual machine of an older version of OS X.

You don't even need to go that far to test the build side of things: on a current Mac with the latest version 
of OS X (10.10.5), I can download an older version of Xcode (5.1.1) which contains the older 10.8 SDK. I can 
build glib 2.46.0 with the 10.8 SDK in that older Xcode (thus somewhat simulating what would happen if you 
were to build on a 10.8 machine) to cause this error to appear:


  CC       libgio_2_0_la-gcocoanotificationbackend.lo
gcocoanotificationbackend.c:225:20: error: property 'identifier' not found on object of type 
'NSUserNotification *'
  userNotification.identifier = str_id;
                   ^
gcocoanotificationbackend.c:226:20: error: property 'contentImage' not found on object of type 
'NSUserNotification *'
  userNotification.contentImage = content;
                   ^
gcocoanotificationbackend.c:254:25: error: property 'identifier' not found on object of type 
'NSUserNotification *'
      if ([notification.identifier compare:str_id] == NSOrderedSame)
                        ^
3 errors generated.