WIP SwiftUI Preview investigation Xcode 16

docs/SwiftUIPreviewInvestigation/Output/Bazel/swiftc_stub.swiftmodule-0.params

@@ -0,0 +1,42 @@
+-target
+x86_64-apple-macos12.0
+-sdk
+__BAZEL_XCODE_SDKROOT__
+-debug-prefix-map
+__BAZEL_XCODE_DEVELOPER_DIR__=/PLACEHOLDER_DEVELOPER_DIR
+-file-prefix-map
+__BAZEL_XCODE_DEVELOPER_DIR__=/PLACEHOLDER_DEVELOPER_DIR
+-emit-object
+-output-file-map
+bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/swiftc_stub.library.output_file_map.json
+-Xfrontend
+-no-clang-module-breadcrumbs
+-emit-module-path
+bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/swiftc_stub.swiftmodule
+-enable-bare-slash-regex
+-DDEBUG
+-Onone
+-Xfrontend
+-no-serialize-debugging-options
+-enable-testing
+-gline-tables-only
+-Xwrapped-swift=-debug-prefix-pwd-is-dot
+-Xwrapped-swift=-file-prefix-pwd-is-dot
+-module-cache-path
+bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/_swift_module_cache
+-Xwrapped-swift=-macro-expansion-dir=bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/swiftc_stub.library.macro-expansions
+-Xcc
+-iquote.
+-Xcc
+-iquotebazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin
+-Xfrontend
+-color-diagnostics
+-enable-batch-mode
+-module-name
+swiftc_stub
+-static
+-Xcc
+-O0
+-Xcc
+-DDEBUG=1
+tools/swiftc_stub/main.swift

docs/SwiftUIPreviewInvestigation/Output/Bazel/swiftc_stub_binary-2.params

@@ -0,0 +1,22 @@
+-lc++
+-Wl,-oso_prefix,__BAZEL_EXECUTION_ROOT__/
+-Wl,-S
+-o
+bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/swiftc_stub_binary
+bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/libswiftc_stub.library.a
+-headerpad_max_install_names
+-Wl,-add_ast_path,bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools/swiftc_stub/swiftc_stub.swiftmodule
+-ObjC
+-L__BAZEL_XCODE_DEVELOPER_DIR__/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/macosx
+-L/usr/lib/swift
+-Wl,-objc_abi_version,2
+-Wl,-rpath,/usr/lib/swift
+-no-canonical-prefixes
+-target
+x86_64-apple-macosx12.0
+-fobjc-link-runtime
+-Xlinker
+-no_deduplicate
+-framework
+Foundation
+-Wl,-no_warn_duplicate_libraries

docs/SwiftUIPreviewInvestigation/Output/Bazel/wrapped_clang_params.IikZ2Y

@@ -0,0 +1,50 @@
+"-D_FORTIFY_SOURCE=1"
+"-fstack-protector"
+"-fcolor-diagnostics"
+"-Wall"
+"-Wthread-safety"
+"-Wself-assign"
+"-fno-omit-frame-pointer"
+"-g0"
+"-O2"
+"-DNDEBUG"
+"-DNS_BLOCK_ASSERTIONS=1"
+"-std=c++14"
+"-fdebug-prefix-map=/Users/oscarberggren/Desktop/rules_xcodeproj-2.9.1/examples/sanitizers/bazel-output-base/rules_xcodeproj.noindex/build_output_base/execroot/__main__=."
+"-fdebug-prefix-map=/Applications/Xcode16.0/Xcode.app/Contents/Developer=/PLACEHOLDER_DEVELOPER_DIR"
+"-iquote"
+"external/build_bazel_rules_swift"
+"-iquote"
+"bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/build_bazel_rules_swift"
+"-iquote"
+"external/com_github_nlohmann_json"
+"-iquote"
+"bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/com_github_nlohmann_json"
+"-isystem"
+"external/com_github_nlohmann_json/include"
+"-isystem"
+"bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/com_github_nlohmann_json/include"
+"-MD"
+"-MF"
+"bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/build_bazel_rules_swift/tools/worker/_objs/worker_protocol/worker_protocol.d"
+"-frandom-seed=bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/build_bazel_rules_swift/tools/worker/_objs/worker_protocol/worker_protocol.o"
+"-isysroot"
+"/Applications/Xcode16.0/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk"
+"-F/Applications/Xcode16.0/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk/System/Library/Frameworks"
+"-F/Applications/Xcode16.0/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks"
+"-no-canonical-prefixes"
+"-pthread"
+"-g0"
+"-g0"
+"-std=c++17"
+"-no-canonical-prefixes"
+"-Wno-builtin-macro-redefined"
+"-D__DATE__=\"redacted\""
+"-D__TIMESTAMP__=\"redacted\""
+"-D__TIME__=\"redacted\""
+"-target"
+"arm64-apple-macosx13.0"
+"-c"
+"external/build_bazel_rules_swift/tools/worker/worker_protocol.cc"
+"-o"
+"bazel-out/darwin_arm64-opt-exec-ST-13d3ddad9198/bin/external/build_bazel_rules_swift/tools/worker/_objs/worker_protocol/worker_protocol.o"

docs/SwiftUIPreviewInvestigation/README.md

@@ -0,0 +1,34 @@
+This is a branch for investigating why SwiftUI Previews have stopped working in Xcode 16, I would love for people to come with inputs and contribute so we can solve this together
+
+# Generating example project
+
+This folder contains a project.yml file that will generate the project when running 'xcodegen generate' 
+
+If xcodegen isn't installed, please visit https://github.com/yonaskolb/XcodeGen#installing and follow the instructions
+
+# How to get Bazel flags
+cd to rules_xcodeproj root and run:
+bazelisk build tools/swiftc_stub:universal_swiftc_stub
+
+This will create a bunch of files in 
+/Users/User/Downloads/rules_xcodeproj/bazel-output-base/execroot/_main/bazel-out/darwin_x86_64-fastbuild-macos-x86_64-min12.0-applebin_macos-ST-50cbb438abaf/bin/tools 
+
+Find the files called “swiftc_stub_binary-2.params” and "swiftc-stub.swiftmodue-0"
+
+Open with TextEdit.
+
+# How to get extended Build log
+
+Open Xcode and go to Target -> Build Phases -> New Run Script Phase
+
+Paste “echo $CFLAGS”
+
+Run the app
+
+Navigate to "Report navigator"
+
+Go to the Build section and press “Export” in the top right corner.
+
+This file will contains C-flags settings in Xcode
+
+# wrapped_clang_params: WIP

docs/SwiftUIPreviewInvestigation/Stubs/clang_shim.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+set -euo pipefail
+
+echo "$@" > $(pwd)/Output/clang_shim_args.txt
+
+while test $# -gt 0
+do
+  case $1 in
+  -MF)
+    shift
+    touch "$1"
+    ;;
+  --serialize-diagnostics)
+    shift
+    cp "${BASH_SOURCE%/*}/cc.dia" "$1"
+    ;;
+  *.o)
+    break
+    ;;
+  -v)
+    # TODO: Make this work with custom toolchains
+    DEV_DIR_PREFIX=$(awk '{ sub(/.*-isysroot /, ""); sub(/.Contents\/Developer.*/, ""); print}' <<< "${@:1}")
+    clang="$DEV_DIR_PREFIX/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"
+    "$clang" "${@:1}"
+    break
+    ;;
+  esac
+
+  shift
+done

docs/SwiftUIPreviewInvestigation/Stubs/ld

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -euo pipefail
+
+echo "$@" > $(pwd)/Output/clang_shim_args.txt
+
+passthrough_args=("${@:1}")
+
+while test $# -gt 0
+do
+  case $1 in
+  *_dependency_info.dat)
+    ld_version=$(ld -v 2>&1 | grep ^@)
+    printf "\0%s\0" "$ld_version" > "$1"
+    break
+    ;;
+
+  -isysroot)
+    shift
+    # PATH/DEVELOPER_DIR isn't set when this is called, so we need to calculate
+    # the developer dir from the sysroot to invoke clang (used below)
+    developer_dir="${1/\/Platforms\/*/}"
+    ;;
+
+  *.preview-thunk.dylib)
+    # Pass through for SwiftUI Preview thunk compilation
+    # TODO: Make this work with custom toolchains
+    exec "$developer_dir/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" "${passthrough_args[@]}"
+    ;;
+  esac
+  shift
+done

docs/SwiftUIPreviewInvestigation/app/Debug.entitlements

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.application-groups</key>
+	<string>group.com.example.core</string>
+</dict>
+</plist>

docs/SwiftUIPreviewInvestigation/app/Info.plist

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleDisplayName</key>
+	<string>MyApp</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+</dict>
+</plist>

docs/SwiftUIPreviewInvestigation/app/sources/ContentView.swift

@@ -0,0 +1,18 @@
+//
+//  ContentView.swift
+//  Core
+//
+//  Created by Oscar Berggren on 12/9/24.
+//
+
+import SwiftUI
+
+struct ContentView: View {
+    var body: some View {
+        Text("Hello, World!")
+    }
+}
+
+#Preview {
+    ContentView()
+}

docs/SwiftUIPreviewInvestigation/app/sources/ExampleProjectApp.swift

@@ -0,0 +1,17 @@
+//
+//  ExampleProjectApp.swift
+//  Core
+//
+//  Created by Oscar Berggren on 12/9/24.
+//
+
+import SwiftUI
+
+@main
+struct ExampleProjectApp: App {
+    var body: some Scene {
+        WindowGroup {
+            ContentView()
+        }
+    }
+}

docs/SwiftUIPreviewInvestigation/project.yml

@@ -0,0 +1,86 @@
+############
+## Project
+############
+name: ExampleProject
+
+############
+## Options
+############
+## In this part we will override some project properties
+
+options:
+  # Select the minimum xcodegen version that could generate this project
+  minimumXcodeGenVersion: 2.10
+
+  # Create empty directories in the final project too
+  generateEmptyDirectories: true
+
+  # Select deployment target. In this particular case will be use iOS, but
+  # we include the example to define it to watchOS, tvOS or macOS
+  deploymentTarget:
+    iOS: "17.4"
+    # watchOS: "6.0"
+    # tvOS: "15.0"
+    # macOS: "11.0"
+
+#############
+## Settings
+#############
+
+settings:
+  # Following properties will be override properties that you could find
+  # into Build settings directory. We will rewrite some for all default variants
+  # created by default for xcodegen, Debug and Release.
+  IPHONEOS_DEPLOYMENT_TARGET: "17.4"
+  MARKETING_VERSION: "1.0.0"
+  CURRENT_PROJECT_VERSION: "1"
+
+############
+## Targets
+############
+
+# Finally we will create our targets. Rememeber we have three of them:
+# - A core package (that will depends on Alamofire)
+# - A test target for this core package
+# - An app target
+
+targets:
+
+  # Name for our app target
+  ExampleProject:
+    # choose application as a type. There a so many types to select here (framework, extensions ...)
+    type: application
+    # choose destination platform
+    platform: iOS
+    deploymentTarget: 17.4
+    sources:
+      # Where app files will be found. Remember you could use patterns and exclusions too!
+      - path: app/sources
+        group: app
+    settings:
+      # Select the bundle identifier
+      PRODUCT_BUNDLE_IDENTIFIER: "com.example.core"
+      CC:
+         - "$(PROJECT_DIR)/Stubs/clang_shim.sh"
+      CXX:
+          - "$(PROJECT_DIR)/Stubs/clang_shim.sh"
+      LD:
+          - "$(PROJECT_DIR)/Stubs/ld"
+      SWIFT_EXEC:
+          - "$(PROJECT_DIR)/Stubs/swiftc"
+
+      # Select where Info.plist will be found
+      INFOPLIST_FILE: app/Info.plist
+      MARKETING_VERSION: 1.0.0
+    postCompileScripts:
+      - script: |
+          echo $CFLAGS
+        name: CFlags
+    entitlements:
+      path: app/Debug.entitlements
+      properties:
+        com.apple.security.application-groups: group.com.example.core
+    info:
+      path: app/Info.plist
+      properties:
+        CFBundleDisplayName: "MyApp"