Add INTERFACE libraries to generated buildsystem if they have SOURCES

INTERFACE libraries were created with the intention of collecting usage
requirements for use by other targets via `target_link_libraries`.
Therefore they were not allowed to have SOURCES and were not included in
the generated buildsystem.  In practice, this has become limiting:

* Header-only libraries do have sources, they just do not compile.
  Developers should be able to edit those sources (the header files)
  in their IDE.

* Header-only libraries may need to generate some of their header
  files via custom commands.

Some projects work around these limitations by pairing each interface
library with an `add_custom_target` that makes the header files and
custom commands appear in the generated buildsystem and in IDEs.

Lift such limitations by allowing INTERFACE libraries to have SOURCES.
For those with sources, add a corresponding build target to the
generated buildsystem.

Fixes: #19145

1 files changed, 18 insertions, 23 deletions

diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 67d7451..51b4e9e 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -401,12 +401,10 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
 #endif
   }
 
-  if (this->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
-    initProp("FOLDER");
+  initProp("FOLDER");
 
-    if (this->GetGlobalGenerator()->IsXcode()) {
-      initProp("XCODE_GENERATE_SCHEME");
-    }
+  if (this->GetGlobalGenerator()->IsXcode()) {
+    initProp("XCODE_GENERATE_SCHEME");
   }
 
   // Setup per-configuration property default values.
@@ -521,24 +519,21 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     initProp("DOTNET_TARGET_FRAMEWORK_VERSION");
   }
 
-  if (this->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
-
-    // check for "CMAKE_VS_GLOBALS" variable and set up target properties
-    // if any
-    const char* globals = mf->GetDefinition("CMAKE_VS_GLOBALS");
-    if (globals) {
-      const std::string genName = mf->GetGlobalGenerator()->GetName();
-      if (cmHasLiteralPrefix(genName, "Visual Studio")) {
-        std::vector<std::string> props = cmExpandedList(globals);
-        const std::string vsGlobal = "VS_GLOBAL_";
-        for (const std::string& i : props) {
-          // split NAME=VALUE
-          const std::string::size_type assignment = i.find('=');
-          if (assignment != std::string::npos) {
-            const std::string propName = vsGlobal + i.substr(0, assignment);
-            const std::string propValue = i.substr(assignment + 1);
-            initPropValue(propName, propValue.c_str());
-          }
+  // check for "CMAKE_VS_GLOBALS" variable and set up target properties
+  // if any
+  const char* globals = mf->GetDefinition("CMAKE_VS_GLOBALS");
+  if (globals) {
+    const std::string genName = mf->GetGlobalGenerator()->GetName();
+    if (cmHasLiteralPrefix(genName, "Visual Studio")) {
+      std::vector<std::string> props = cmExpandedList(globals);
+      const std::string vsGlobal = "VS_GLOBAL_";
+      for (const std::string& i : props) {
+        // split NAME=VALUE
+        const std::string::size_type assignment = i.find('=');
+        if (assignment != std::string::npos) {
+          const std::string propName = vsGlobal + i.substr(0, assignment);
+          const std::string propValue = i.substr(assignment + 1);
+          initPropValue(propName, propValue.c_str());
         }
       }
     }