cmComputeLinkInformation: prepare Item consumers for `OBJECT` libraries

After b665966933 (cmComputeLinkInformation: track `OBJECT` library
dependencies, 2023-07-22), introduced in !8645 as a fix for #25112,
`OBJECT` libraries were tracked in a separate member to reduce the risk
of further regressions. This commit prepares consumers to handle
`OBJECT` libraries once they start appearing as link items.

Source/cmExportFileGenerator.cxx

@@ -536,7 +536,7 @@ static void getCompatibleInterfaceProperties(
   const cmComputeLinkInformation::ItemVector& deps = info->GetItems();
 
   for (auto const& dep : deps) {
-    if (!dep.Target) {
+    if (!dep.Target || dep.Target->GetType() == cmStateEnums::OBJECT_LIBRARY) {
       continue;
     }
     getPropertyContents(dep.Target, "COMPATIBLE_INTERFACE_BOOL",

Source/cmGeneratorTarget.cxx

@@ -5858,7 +5858,7 @@ void cmGeneratorTarget::CheckPropertyCompatibility(
   static const std::string strNumMax = "COMPATIBLE_INTERFACE_NUMBER_MAX";
 
   for (auto const& dep : deps) {
-    if (!dep.Target) {
+    if (!dep.Target || dep.Target->GetType() == cmStateEnums::OBJECT_LIBRARY) {
       continue;
     }
 

Source/cmGlobalXCodeGenerator.cxx

@@ -3598,6 +3598,13 @@ void cmGlobalXCodeGenerator::AddDependAndLinkInformation(cmXCodeObject* target)
       continue;
     }
     for (auto const& libItem : cli->GetItems()) {
+      // Explicitly ignore OBJECT libraries as Xcode emulates them as static
+      // libraries without an artifact. Avoid exposing this to the rest of
+      // CMake's compilation model.
+      if (libItem.Target &&
+          libItem.Target->GetType() == cmStateEnums::OBJECT_LIBRARY) {
+        continue;
+      }
       // We want to put only static libraries, dynamic libraries, frameworks
       // and bundles that are built from targets that are not imported in "Link
       // Binary With Libraries" build phase. Except if the target property

Source/cmLinkLineComputer.cxx

@@ -65,7 +65,8 @@ void cmLinkLineComputer::ComputeLinkLibs(
   ItemVector const& items = cli.GetItems();
   for (auto const& item : items) {
     if (item.Target &&
-        item.Target->GetType() == cmStateEnums::INTERFACE_LIBRARY) {
+        (item.Target->GetType() == cmStateEnums::INTERFACE_LIBRARY ||
+         item.Target->GetType() == cmStateEnums::OBJECT_LIBRARY)) {
       continue;
     }
 

Source/cmLinkLineDeviceComputer.cxx

@@ -115,6 +115,7 @@ void cmLinkLineDeviceComputer::ComputeLinkLibraries(
       switch (item.Target->GetType()) {
         case cmStateEnums::SHARED_LIBRARY:
         case cmStateEnums::MODULE_LIBRARY:
+        case cmStateEnums::OBJECT_LIBRARY:
         case cmStateEnums::INTERFACE_LIBRARY:
           skip = true;
           break;

Source/cmLocalVisualStudio7Generator.cxx

@@ -1318,7 +1318,8 @@ void cmLocalVisualStudio7GeneratorInternals::OutputLibraries(
       fout << (lib.HasFeature() ? lib.GetFormattedItem(rel).Value : rel)
            << " ";
     } else if (!lib.Target ||
-               lib.Target->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
+               (lib.Target->GetType() != cmStateEnums::INTERFACE_LIBRARY &&
+                lib.Target->GetType() != cmStateEnums::OBJECT_LIBRARY)) {
       fout << lib.Value.Value << " ";
     }
   }

Source/cmVisualStudio10TargetGenerator.cxx

@@ -4603,7 +4603,8 @@ void cmVisualStudio10TargetGenerator::AddLibraries(
                                         : path);
       }
     } else if (!l.Target ||
-               l.Target->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
+               (l.Target->GetType() != cmStateEnums::INTERFACE_LIBRARY &&
+                l.Target->GetType() != cmStateEnums::OBJECT_LIBRARY)) {
       libVec.push_back(l.Value.Value);
     }
   }