Set SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG in the Debug config#244
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radoslawrolka wants to merge 1 commit into
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Set SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG in the Debug config#244radoslawrolka wants to merge 1 commit into
radoslawrolka wants to merge 1 commit into
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The app template's AppDelegate.swift gates the Metro bundle URL behind `#if DEBUG` (falling back to a non-existent main.jsbundle otherwise). In Swift, `#if DEBUG` is controlled by SWIFT_ACTIVE_COMPILATION_CONDITIONS, not by GCC_PREPROCESSOR_DEFINITIONS (which only affects C/ObjC/C++). Today this flag is not committed in project.pbxproj; it is injected at `pod install` time by react_native_post_install (react_native_pods.rb), which calls set_build_setting for SWIFT_ACTIVE_COMPILATION_CONDITIONS = ["$(inherited)", "DEBUG"] on the user project's Debug config. That means any setup that does not run CocoaPods (e.g. Swift Package Manager react-native experimental setup) never gets the flag, so `#if DEBUG` is false even in Debug builds. bundleURL() then returns nil and the app fails to launch with "No script url provided ... unsanitizedScriptURLString = (null)", even though Metro is running. Baking the setting into the template makes Debug builds work regardless of the dependency manager and matches the value CocoaPods already sets, so CocoaPods-based apps are unaffected.
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I think we should merge this one, @radoslawrolka :) Makes a lot of sense - since this is the App's code it should be here - and not in the SwiftPM manifest generators. |
radoslawrolka
marked this pull request as ready for review
July 24, 2026 07:58
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Summary:
The app template's AppDelegate.swift gates the Metro bundle URL behind
#if DEBUG(falling back to a non-existent main.jsbundle otherwise). In Swift,#if DEBUGis controlled by SWIFT_ACTIVE_COMPILATION_CONDITIONS, not by GCC_PREPROCESSOR_DEFINITIONS (which only affects C/ObjC/C++).Today this flag is not committed in project.pbxproj; it is injected at
pod installtime by react_native_post_install (react_native_pods.rb), which calls set_build_setting for SWIFT_ACTIVE_COMPILATION_CONDITIONS = ["$(inherited)", "DEBUG"] on the user project's Debug config.That means any setup that does not run CocoaPods (e.g. Swift Package Manager react-native experimental setup) never gets the flag, so
#if DEBUGis false even in Debug builds. bundleURL() then returns nil and the app fails to launch with "No script url provided ... unsanitizedScriptURLString = (null)", even though Metro is running.Baking the setting into the template makes Debug builds work regardless of the dependency manager and matches the value CocoaPods already sets, so CocoaPods-based apps are unaffected.
Changelog:
[IOS] [FIXED] - added missing SWIFT_ACTIVE_COMPILATION_CONDITIONS in debug config
Test Plan:
building app without coocapods (react/react-native #57332)