install: Teach EXPORT option to handle INTERFACE_LIBRARY targets

Source/cmExportInstallFileGenerator.cxx

@@ -114,6 +114,7 @@ bool cmExportInstallFileGenerator::GenerateMainFile(std::ostream& os)
   std::vector<std::string> missingTargets;
 
   bool require2_8_12 = false;
+  bool require2_8_13 = false;
   // Create all the imported targets.
   for(std::vector<cmTargetExport*>::const_iterator
         tei = allTargets.begin();
@@ -153,6 +154,10 @@ bool cmExportInstallFileGenerator::GenerateMainFile(std::ostream& os)
         require2_8_12 = true;
         }
       }
+    if (te->GetType() == cmTarget::INTERFACE_LIBRARY)
+      {
+      require2_8_13 = true;
+      }
     this->PopulateInterfaceProperty("INTERFACE_POSITION_INDEPENDENT_CODE",
                                   te, properties);
     this->PopulateCompatibleInterfaceProperties(te, properties);
@@ -160,7 +165,11 @@ bool cmExportInstallFileGenerator::GenerateMainFile(std::ostream& os)
     this->GenerateInterfaceProperties(te, os, properties);
     }
 
-  if (require2_8_12)
+  if (require2_8_13)
+    {
+    this->GenerateRequiredCMakeVersion(os, "2.8.12.20131007");
+    }
+  else if (require2_8_12)
     {
     this->GenerateRequiredCMakeVersion(os, "2.8.12");
     }
@@ -286,6 +295,14 @@ cmExportInstallFileGenerator
     cmTargetExport const* te = *tei;
     ImportPropertyMap properties;
     std::set<std::string> importedLocations;
+    if (!properties.empty()
+        && te->Target->GetType() == cmTarget::INTERFACE_LIBRARY)
+      {
+      this->GenerateImportPropertyCode(os, config, te->Target, properties);
+      this->GenerateImportedFileChecksCode(os, te->Target, properties,
+                                           importedLocations);
+      continue;
+      }
     this->SetImportLocationProperty(config, suffix, te->ArchiveGenerator,
                                     properties, importedLocations);
     this->SetImportLocationProperty(config, suffix, te->LibraryGenerator,

Source/cmInstallCommand.cxx

@@ -379,7 +379,8 @@ bool cmInstallCommand::HandleTargetsMode(std::vector<std::string> const& args)
          target->GetType() != cmTarget::STATIC_LIBRARY &&
          target->GetType() != cmTarget::SHARED_LIBRARY &&
          target->GetType() != cmTarget::MODULE_LIBRARY &&
-         target->GetType() != cmTarget::OBJECT_LIBRARY)
+         target->GetType() != cmTarget::OBJECT_LIBRARY &&
+         target->GetType() != cmTarget::INTERFACE_LIBRARY)
         {
         cmOStringStream e;
         e << "TARGETS given target \"" << (*targetIt)
@@ -626,6 +627,11 @@ bool cmInstallCommand::HandleTargetsMode(std::vector<std::string> const& args)
           }
         }
         break;
+      case cmTarget::INTERFACE_LIBRARY:
+          // Nothing to do. An INTERFACE_LIBRARY can be installed, but the
+          // only effect of that is to make it exportable. It installs no
+          // other files itself.
+        break;
       default:
         // This should never happen due to the above type check.
         // Ignore the case.

Tests/ExportImport/Export/Interface/CMakeLists.txt

@@ -27,3 +27,23 @@ export(TARGETS sharediface sharedlib headeronly
   NAMESPACE bld_
   FILE ../ExportInterfaceBuildTree.cmake
 )
+
+install(TARGETS headeronly sharediface sharedlib
+  EXPORT expInterface
+  RUNTIME DESTINATION bin
+  LIBRARY DESTINATION lib NAMELINK_SKIP
+  ARCHIVE DESTINATION lib
+  FRAMEWORK DESTINATION Frameworks
+  BUNDLE DESTINATION Applications
+)
+install(FILES
+  headeronly/headeronly.h
+  DESTINATION include/headeronly
+)
+install(FILES
+  sharedlib/sharedlib.h
+  "${CMAKE_CURRENT_BINARY_DIR}/sharedlib_export.h"
+  DESTINATION include/sharedlib
+)
+
+install(EXPORT expInterface NAMESPACE exp_ DESTINATION lib/exp)

Tests/ExportImport/Import/Interface/CMakeLists.txt

@@ -2,6 +2,9 @@
 # Import targets from the exported build tree.
 include(${Import_BINARY_DIR}/../Export/ExportInterfaceBuildTree.cmake)
 
+# Import targets from the exported install tree.
+include(${CMAKE_INSTALL_PREFIX}/lib/exp/expInterface.cmake)
+
 add_library(define_iface INTERFACE)
 set_property(TARGET define_iface PROPERTY
   INTERFACE_COMPILE_DEFINITIONS DEFINE_IFACE_DEFINE)
@@ -40,3 +43,13 @@ macro(do_try_compile prefix)
 endmacro()
 
 do_try_compile(bld_)
+
+add_executable(headeronlytest_exp headeronlytest.cpp)
+target_link_libraries(headeronlytest_exp exp_headeronly)
+
+set_property(TARGET exp_sharediface APPEND PROPERTY INTERFACE_LINK_LIBRARIES define_iface)
+
+add_executable(interfacetest_exp interfacetest.cpp)
+target_link_libraries(interfacetest_exp exp_sharediface)
+
+do_try_compile(exp_)