Apple: Fix linking to frameworks that do not exist until build time

Fixes: #21621

Source/cmComputeLinkInformation.cxx

@@ -699,9 +699,13 @@ void cmComputeLinkInformation::AddItem(BT<std::string> const& item,
   } else {
     // This is not a CMake target.  Use the name given.
     if (cmSystemTools::FileIsFullPath(item.Value)) {
-      if (cmSystemTools::FileIsDirectory(item.Value)) {
+      if (cmSystemTools::IsPathToFramework(item.Value) &&
+          this->Makefile->IsOn("APPLE")) {
+        // This is a framework.
+        this->AddFrameworkItem(item.Value);
+      } else if (cmSystemTools::FileIsDirectory(item.Value)) {
         // This is a directory.
-        this->AddDirectoryItem(item.Value);
+        this->DropDirectoryItem(item.Value);
       } else {
         // Use the full path given to the library file.
         this->Depends.push_back(item.Value);
@@ -1306,16 +1310,6 @@ void cmComputeLinkInformation::AddFrameworkItem(std::string const& item)
   }
 }
 
-void cmComputeLinkInformation::AddDirectoryItem(std::string const& item)
-{
-  if (this->Makefile->IsOn("APPLE") &&
-      cmSystemTools::IsPathToFramework(item)) {
-    this->AddFrameworkItem(item);
-  } else {
-    this->DropDirectoryItem(item);
-  }
-}
-
 void cmComputeLinkInformation::DropDirectoryItem(std::string const& item)
 {
   // A full path to a directory was found as a link item.  Warn the

Source/cmComputeLinkInformation.h

@@ -155,7 +155,6 @@ private:
   void AddFullItem(BT<std::string> const& item);
   bool CheckImplicitDirItem(std::string const& item);
   void AddUserItem(BT<std::string> const& item, bool pathNotKnown);
-  void AddDirectoryItem(std::string const& item);
   void AddFrameworkItem(std::string const& item);
   void DropDirectoryItem(std::string const& item);
   bool CheckSharedLibNoSOName(std::string const& item);

Tests/Framework/CMakeLists.txt

@@ -84,3 +84,19 @@ if(NOT XCODE OR NOT XCODE_VERSION VERSION_LESS 5)
 endif()
 
 include(CPack)
+
+if(APPLE)
+  set(ExternalFramework_INSTALL_DIR "${CMAKE_CURRENT_BINARY_DIR}/External")
+  file(REMOVE_RECURSE "${ExternalFramework_INSTALL_DIR}")
+
+  include(ExternalProject)
+  ExternalProject_Add(ExternalFramework
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/External"
+    INSTALL_DIR "${ExternalFramework_INSTALL_DIR}"
+    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+  )
+
+  add_executable(useExternal useExternal.c)
+  target_link_libraries(useExternal PRIVATE "${ExternalFramework_INSTALL_DIR}/lib/External.framework")
+  add_dependencies(useExternal ExternalFramework)
+endif()

Tests/Framework/External/CMakeLists.txt

@@ -0,0 +1,5 @@
+cmake_minimum_required(VERSION 3.19)
+project(ExternalFramework C)
+add_library(External SHARED external.c)
+set_property(TARGET External PROPERTY FRAMEWORK 1)
+install(TARGETS External DESTINATION lib)

Tests/Framework/External/external.c

@@ -0,0 +1,4 @@
+int external(void)
+{
+  return 0;
+}

Tests/Framework/useExternal.c

@@ -0,0 +1,6 @@
+extern int external(void);
+
+int main(void)
+{
+  return external();
+}