Add directory property to list buildsystem targets

Add a BUILDSYSTEM_TARGETS property to allow project code to traverse
the list of its own targets in a given directory.

Help/manual/cmake-properties.7.rst

@@ -54,6 +54,7 @@ Properties on Directories
    :maxdepth: 1
 
    /prop_dir/ADDITIONAL_MAKE_CLEAN_FILES
+   /prop_dir/BUILDSYSTEM_TARGETS
    /prop_dir/CACHE_VARIABLES
    /prop_dir/CLEAN_NO_CUSTOM
    /prop_dir/CMAKE_CONFIGURE_DEPENDS

Help/prop_dir/BUILDSYSTEM_TARGETS.rst

@@ -0,0 +1,11 @@
+BUILDSYSTEM_TARGETS
+-------------------
+
+This read-only directory property contains a
+:ref:`;-list <CMake Language Lists>` of buildsystem targets added in the
+directory by calls to the :command:`add_library`, :command:`add_executable`,
+and :command:`add_custom_target` commands.  The list does not include any
+:ref:`Imported Targets` or :ref:`Alias Targets`, but does include
+:ref:`Interface Libraries`.  Each entry in the list is the logical name
+of a target, suitable to pass to the :command:`get_property` command
+``TARGET`` option.

Help/release/dev/directory-list-targets-and-subdirs.rst

@@ -1,5 +1,9 @@
 directory-list-targets-and-subdirs
 ----------------------------------
 
+* A :prop_dir:`BUILDSYSTEM_TARGETS` directory property was added to
+  get the list of logical buildsystem target names added by the
+  project in a directory.
+
 * A :prop_dir:`SUBDIRECTORIES` directory property was added to
   get the list of subdirectories added by a project in a directory.

Source/cmState.cxx

@@ -29,6 +29,7 @@
 #include <string.h>
 #include <utility>
 
+static std::string const kBUILDSYSTEM_TARGETS = "BUILDSYSTEM_TARGETS";
 static std::string const kSUBDIRECTORIES = "SUBDIRECTORIES";
 
 struct cmState::SnapshotDataType
@@ -1683,6 +1684,10 @@ const char* cmState::Directory::GetProperty(const std::string& prop,
     output = cmJoin(child_dirs, ";");
     return output.c_str();
   }
+  if (prop == kBUILDSYSTEM_TARGETS) {
+    output = cmJoin(this->DirectoryState->NormalTargetNames, ";");
+    return output.c_str();
+  }
 
   if (prop == "LISTFILE_STACK") {
     std::vector<std::string> listFiles;

Tests/RunCMake/get_property/directory_properties-stderr.txt

@@ -7,4 +7,8 @@ get_property: --><--
 get_directory_property: -->[^<;]*Tests/RunCMake/get_property/directory_properties<--
 get_property: -->[^<;]*Tests/RunCMake/get_property/directory_properties<--
 get_directory_property: -->[^<;]*Tests/RunCMake/get_property/directory_properties/sub1;[^<;]*Tests/RunCMake/get_property/directory_properties/sub2<--
-get_property: -->[^<;]*Tests/RunCMake/get_property/directory_properties/sub1;[^<;]*Tests/RunCMake/get_property/directory_properties/sub2<--$
+get_property: -->[^<;]*Tests/RunCMake/get_property/directory_properties/sub1;[^<;]*Tests/RunCMake/get_property/directory_properties/sub2<--
+get_directory_property: -->CustomTop;InterfaceTop<--
+get_property: -->CustomTop;InterfaceTop<--
+get_directory_property: -->CustomSub;InterfaceSub<--
+get_property: -->CustomSub;InterfaceSub<--$

Tests/RunCMake/get_property/directory_properties.cmake

@@ -14,6 +14,12 @@ check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}" empty)
 check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}" custom)
 check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}" noexist)
 
+add_custom_target(CustomTop)
+add_library(InterfaceTop INTERFACE)
+add_library(my::InterfaceTop ALIAS InterfaceTop)
+
 add_subdirectory(directory_properties)
 check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}" SUBDIRECTORIES)
 check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}/directory_properties" SUBDIRECTORIES)
+check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}" BUILDSYSTEM_TARGETS)
+check_directory_property("${CMAKE_CURRENT_SOURCE_DIR}/directory_properties" BUILDSYSTEM_TARGETS)

Tests/RunCMake/get_property/directory_properties/CMakeLists.txt

@@ -1,2 +1,6 @@
 add_subdirectory(sub1)
 subdirs(sub2)
+
+add_custom_target(CustomSub)
+add_library(InterfaceSub INTERFACE)
+add_library(my::InterfaceSub ALIAS InterfaceSub)