iOS: only exclude i386 while using hermes

[jpdriver]

Summary:

• if an existing iOS project specifies EXCLUDED_ARCHS, these settings are overwritten by the react_native_post_install step as part of the Cocoapods install
• closes react_native_post_install set main project EXCLUDED_ARCHS[sdk=iphonesimulator*] to empty string in iOS #35544

Existing Behaviour

• one of the functions called as part of the react_native_post_install step is exclude_i386_architecture_while_using_hermes
  • see /packages/react-native/scripts/cocoapods/utils.rb

    def self.exclude_i386_architecture_while_using_hermes(installer)
        projects = self.extract_projects(installer)

        # Hermes does not support `i386` architecture
        excluded_archs_default = self.has_pod(installer, 'hermes-engine') ? "i386" : ""

        projects.each do |project|
            project.build_configurations.each do |config|
                config.build_settings["EXCLUDED_ARCHS[sdk=iphonesimulator*]"] = excluded_archs_default
            end

            project.save()
        end
    end

🐛 However 🐛

• this function is currently called regardless of whether or not you are actually using Hermes
• this means existing projects that have EXCLUDED_ARCHS set, the existing value will be changed either to "i386" or a blank string

Changed Behaviour

• moved the function call inside an if ReactNativePodsUtils.has_pod(installer, "React-hermes") block
• EXCLUDED_ARCHS should only be modified if needed now

Changelog:

[IOS] [FIXED] Only modify EXCLUDED_ARCHS when needed for Hermes

Test Plan:

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	9,060,768	-2
android	hermes	armeabi-v7a	8,310,099	+2
android	hermes	x86	9,576,980	+0
android	hermes	x86_64	9,419,403	-1
android	jsc	arm64-v8a	9,613,486	+1
android	jsc	armeabi-v7a	8,740,120	+2
android	jsc	x86	9,700,430	-2
android	jsc	x86_64	9,946,999	+0

Base commit: ebc1fe6
Branch: main

[cipolleschi]

Thank you so much for doing this. I think it slipped away while refactoring the cocoapods scripts. 🤦

[facebook-github-bot]

@cipolleschi has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[cipolleschi]

/rebase

[facebook-github-bot]

@cipolleschi has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[cipolleschi]

/rebase

[facebook-github-bot]

@cipolleschi has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[github-actions]

This pull request was successfully merged by @jpdriver in ee1cd13.

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