Add minimum required OS version setting to macOS and iOS exports

[lostminds]

Describe the project you are working on

A multi-platform game I'll try to get published via the Apple App Store and other platforms

Describe the problem or limitation you are having in your project

On macOS and iOS (and possible other plattforms) apps have a minimum required OS version specified in them. This provides a nice message on unsupported OS versions if you try to run the app (instead of it just crashing) and is also used in the App Store to inform you your device can't run the app before you download it.

As far as I can tell via testing using the Mobile Vulkan renderer in Godot 4 you need macOS 10.15 or later and iOS 16 or later to be sure that the device can run the game (as discussed here). However, when exporting Godot seems to set no macOS minimum required version (which defaults to macOS 10.12) and sets iOS 12 as the minimum required iOS version. In both cases this means the game will be distributed to and be possible to launch on devices where it will just show a black screen.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

One solution would of course be to correctly set these limits based on what the engine requires for your project, but this can be hard to know and get right. So I propose at least adding a field in the export dialogue where you can specify the macOS and iOS version that should be specified as the minimum required version for the export. Then you as the developer at least have control over this and can set it consistently for your exports.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Add fields to the export settings for macOS and iOS.

When building add these fields to the appropriate info.plist fields of the bundle for macOS:

<key>LSMinimumSystemVersion</key>
<string>10.15</string>
<key>LSMinimumSystemVersionByArchitecture</key>
<dict>
  <key>x86_64</key>
  <string>10.15</string>
</dict>

For iOS the value needs to be set in the xcode build target as the IPHONEOS_DEPLOYMENT_TARGET key in the buildSettings dictionary. For example

D0BCFE7318AEBDA3004A7AAE /* Release */ = {
        isa = XCBuildConfiguration;
	buildSettings = {
		...
		IPHONEOS_DEPLOYMENT_TARGET = 16.0;
		...
	};
	name = Release;
};

If this enhancement will not be used often, can it be worked around with a few lines of script?

You can work around it on macOS by exporting the game unsigned, editing the info.plist manually and then manually signing and notarizing it via terminal.
On iOS you can edit the information in XCode before building it there.

Is there a reason why this should be core and not an add-on in the asset library?

It's a hassle to need to do these extra steps on each export, and it would be better if it was correctly set when you export it from Godot.

It would probably also be a good idea to then bump up the default values for these since I think the current minimum required macOS and iOS values will likely be wrong in for all exports unless they're using the compatibility renderer.

[Calinou]

Exporting a project that uses a Vulkan backend without OpenGL fallback being enabled should automatically use 10.15 as minimum macOS version, and iOS 16 as minimum iOS version.

Overriding these limits on a per-project basis can make sense for projects using custom modules or GDExtensions that rely on newer OS functionality still.

[bruvzg]

However, when exporting Godot seems to set no macOS minimum required version (which defaults to macOS 10.12)

It's not missing, it is set to 10.12, since it's what is min. version for OpenGL export is (for Vulkan it's 10.14, but it depends on hardware so probably should be 10.15 or user configurable on export).

https://github.com/godotengine/godot/blob/c0f1ed57c44253c88a7d27e9727a305fb2155e51/misc/dist/macos_template.app/Contents/Info.plist#L38-L44

[lostminds]

It's not missing, it is set to 10.12

Ah, you're right. Sorry for the confusion. I based this on output from the productbuild tool used to create installer (and mac app store) packages. I interpreted the output productbuild: Supported OS versions: [Min: 10.12, Before: None] as the macOS app bundle missing minimum OS info, but I guess that means something else. I checked now and it does indeed seem to be set to 10.12 in the info.plist.

Overriding these limits on a per-project basis can make sense for projects using custom modules or GDExtensions that rely on newer OS functionality still.

I think so. Implicitly this could also be used to control if you want to use the automatic fallback to the compatibility renderer. In other words if you want to prioritize the widest device compatibility or if you want to prioritize ensuring renderer feature support but exclude older devices. Since if you for example set the minimum version to iOS16 I believe all such iOS devices will support the vulkan backend, so it will never fall back to compatibility (even if it could do so automatically in the future).