Improved Application Extension scheme generation (#932)

* Default extensions to launchAutomaticallySubstyle "2"

* Don't use debugger launcher with extensions

Xcode schemes don't use the LLDB launcher, even when debugging is enabled.

Co-authored-by: Yonas Kolb <yonaskolb@users.noreply.github.com>

CHANGELOG.md

@@ -6,6 +6,7 @@
 - Add `Scheme.Test.TestTarget.skipped` to allow skipping of an entire test target. [#916](https://github.com/yonaskolb/XcodeGen/pull/916) @codeman9
 - Added ability to set custom LLDBInit scripts for launch and test schemes [#929](https://github.com/yonaskolb/XcodeGen/pull/929) @polac24
 - Adds App Clip support. [#909](https://github.com/yonaskolb/XcodeGen/pull/909) @brentleyjones @dflems
+- Application extension schemes now default to `launchAutomaticallySubstyle = 2` and the correct debugger and launcher identifiers [#932](https://github.com/yonaskolb/XcodeGen/pull/932) @brentleyjones
 
 #### Internal
 - Updates CI to run on Xcode 12 beta. [#936](https://github.com/yonaskolb/XcodeGen/pull/936) @dflems
@@ -23,7 +24,7 @@
 #### Fixed
 - Treat all directories with known UTI as file wrapper. [#896](https://github.com/yonaskolb/XcodeGen/pull/896) @KhaosT
 - Generated schemes for application extensions now contain `wasCreatedForAppExtension = YES`. [#898](https://github.com/yonaskolb/XcodeGen/issues/898) @muizidn
-- Allow package dependencies to use `link: false` [#920](https://github.com/yonaskolb/XcodeGen/pull/920) @k-thorat   
+- Allow package dependencies to use `link: false` [#920](https://github.com/yonaskolb/XcodeGen/pull/920) @k-thorat
 - Fixed issue computing relative paths.  [#915](https://github.com/yonaskolb/XcodeGen/pull/915) @andrewreach
 
 #### Internal

Sources/XcodeGenKit/SchemeGenerator.swift

@@ -240,8 +240,8 @@ public class SchemeGenerator {
             preActions: scheme.run?.preActions.map(getExecutionAction) ?? [],
             postActions: scheme.run?.postActions.map(getExecutionAction) ?? [],
             macroExpansion: shouldExecuteOnLaunch ? nil : buildableReference,
-            selectedDebuggerIdentifier: (scheme.run?.debugEnabled ?? Scheme.Run.debugEnabledDefault) ? XCScheme.defaultDebugger : "",
-            selectedLauncherIdentifier: (scheme.run?.debugEnabled ?? Scheme.Run.debugEnabledDefault) ? XCScheme.defaultLauncher : "Xcode.IDEFoundation.Launcher.PosixSpawn",
+            selectedDebuggerIdentifier: selectedDebuggerIdentifier(for: schemeTarget, run: scheme.run),
+            selectedLauncherIdentifier: selectedLauncherIdentifier(for: schemeTarget, run: scheme.run),
             askForAppToLaunch: scheme.run?.askForAppToLaunch,
             allowLocationSimulation: allowLocationSimulation,
             locationScenarioReference: locationScenarioReference,
@@ -251,7 +251,7 @@ public class SchemeGenerator {
             environmentVariables: launchVariables,
             language: scheme.run?.language,
             region: scheme.run?.region,
-            launchAutomaticallySubstyle: scheme.run?.launchAutomaticallySubstyle,
+            launchAutomaticallySubstyle: scheme.run?.launchAutomaticallySubstyle ?? launchAutomaticallySubstyle(for: schemeTarget),
             customLLDBInitFile: scheme.run?.customLLDBInit
         )
 
@@ -290,6 +290,14 @@ public class SchemeGenerator {
         )
     }
 
+    private func launchAutomaticallySubstyle(for target: Target?) -> String? {
+        if target?.type.isExtension == true {
+            return "2"
+        } else {
+            return nil
+        }
+    }
+
     private func makeProductRunnables(for target: Target?, buildableReference: XCScheme.BuildableReference) -> (launch: XCScheme.Runnable, profile: XCScheme.BuildableProductRunnable) {
         let buildable = XCScheme.BuildableProductRunnable(buildableReference: buildableReference)
         if target?.type.isWatchApp == true {
@@ -303,6 +311,22 @@ public class SchemeGenerator {
             return (buildable, buildable)
         }
     }
+
+    private func selectedDebuggerIdentifier(for target: Target?, run: Scheme.Run?) -> String {
+        if target?.type.canUseDebugLauncher != false && run?.debugEnabled ?? Scheme.Run.debugEnabledDefault {
+            return XCScheme.defaultDebugger
+        } else {
+            return ""
+        }
+    }
+
+    private func selectedLauncherIdentifier(for target: Target?, run: Scheme.Run?) -> String {
+        if target?.type.canUseDebugLauncher != false && run?.debugEnabled ?? Scheme.Run.debugEnabledDefault {
+            return XCScheme.defaultLauncher
+        } else {
+            return "Xcode.IDEFoundation.Launcher.PosixSpawn"
+        }
+    }
 }
 
 enum SchemeGenerationError: Error, CustomStringConvertible {
@@ -380,6 +404,11 @@ extension Scheme {
 }
 
 extension PBXProductType {
+    var canUseDebugLauncher: Bool {
+        // Extensions don't use the lldb launcher
+        return !isExtension
+    }
+
     var isWatchApp: Bool {
         switch self {
         case .watchApp, .watch2App:

Tests/Fixtures/TestProject/Project.xcodeproj/xcshareddata/xcschemes/iMessageExtension.xcscheme

@@ -45,14 +45,15 @@
    </TestAction>
    <LaunchAction
       buildConfiguration = "Production Debug"
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      selectedDebuggerIdentifier = ""
+      selectedLauncherIdentifier = "Xcode.IDEFoundation.Launcher.PosixSpawn"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
-      allowLocationSimulation = "YES">
+      allowLocationSimulation = "YES"
+      launchAutomaticallySubstyle = "2">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">
          <BuildableReference

Tests/Fixtures/TestProject/ProjectXcode12.xcodeproj/xcshareddata/xcschemes/iMessageExtension.xcscheme

@@ -45,14 +45,15 @@
    </TestAction>
    <LaunchAction
       buildConfiguration = "Production Debug"
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      selectedDebuggerIdentifier = ""
+      selectedLauncherIdentifier = "Xcode.IDEFoundation.Launcher.PosixSpawn"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
-      allowLocationSimulation = "YES">
+      allowLocationSimulation = "YES"
+      launchAutomaticallySubstyle = "2">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">
          <BuildableReference