Use REXML instead, default back to no key in xcheme, aka, enabled

Author: Saadnajmi

example/app.json

@@ -13,9 +13,6 @@
       "presentationStyle": "modal"
     }
   ],
-  "ios": {
-    "metalAPIValidation": true
-  },
   "resources": {
     "android": [
       "dist/res",

example/ios/Podfile.lock

@@ -1712,11 +1712,11 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   boost: 4cb898d0bf20404aab1850c656dcea009429d6c1
-  DoubleConversion: fea03f2699887d960129cc54bba7e52542b6f953
+  DoubleConversion: 76ab83afb40bddeeee456813d9c04f67f78771b5
   Example-Tests: fc629729804712c34ae6c28b9fc1c45619f6636d
   FBLazyVector: 430e10366de01d1e3d57374500b1b150fe482e6d
   fmt: 4c2741a687cc09f0634a2e2c72a838b99f1ff120
-  glog: c5d68082e772fa1c511173d6b30a9de2c05a69a2
+  glog: 69ef571f3de08433d766d614c73a9838a06bf7eb
   RCT-Folly: 4464f4d875961fce86008d45f4ecf6cef6de0740
   RCTDeprecation: 726d24248aeab6d7180dac71a936bbca6a994ed1
   RCTRequired: a94e7febda6db0345d207e854323c37e3a31d93b

ios/ReactTestApp.xcodeproj/xcshareddata/xcschemes/ReactTestApp.xcscheme

@@ -59,7 +59,6 @@
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
-      enableGPUValidationMode = "1"
       allowLocationSimulation = "YES">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">

ios/xcode.rb

@@ -1,3 +1,6 @@
+require 'rexml/document'
+require 'rexml/xpath'
+
 IPHONEOS_DEPLOYMENT_TARGET = 'IPHONEOS_DEPLOYMENT_TARGET'.freeze
 MACOSX_DEPLOYMENT_TARGET = 'MACOSX_DEPLOYMENT_TARGET'.freeze
 XROS_DEPLOYMENT_TARGET = 'XROS_DEPLOYMENT_TARGET'.freeze
@@ -25,13 +28,16 @@ def configure_xcschemes!(xcschemes_path, project_root, target_platform, name)
   xcscheme = File.join(xcschemes_path, "ReactTestApp.xcscheme")
   metal_api_validation = platform_config('metalAPIValidation', project_root, target_platform)
 
-  # Oddly enough, to disable Metal API validation, we need to remove the `enableGPUValidationMode` key from the xcscheme file.
-  # A default Xcode project does not have this key, so lets follow that pattern and only add it if it is enabled.
-  if metal_api_validation.nil? || metal_api_validation == true
+
+  # Oddly enough, to disable Metal API validation, we need to add `enableGPUValidationMode = "1"` to the xcscheme Launch Action.
+  if metal_api_validation == false
     xcscheme_content = File.read(xcscheme)
-    new_content = xcscheme_content.gsub(/^\s*enableGPUValidationMode\s*=\s*"1"\s*$/, '')
-    File.write(xcscheme, new_content)
-    return
+    doc = REXML::Document.new(xcscheme_content)
+    doc.root.elements['LaunchAction'].attributes['enableGPUValidationMode'] = '1'
+
+    File.open(xcscheme, 'w') do |file|
+      doc.write(file)
+    end
   end
 
   # Make a copy of the ReactTestApp.xcscheme file with the app name for convenience.