Add a getter for manually added target dependencies

Closes: #16165

Help/manual/cmake-properties.7.rst

@@ -236,6 +236,7 @@ Properties on Targets
    /prop_tgt/MACOSX_BUNDLE
    /prop_tgt/MACOSX_FRAMEWORK_INFO_PLIST
    /prop_tgt/MACOSX_RPATH
+   /prop_tgt/MANUALLY_ADDED_DEPENDENCIES
    /prop_tgt/MAP_IMPORTED_CONFIG_CONFIG
    /prop_tgt/NAME
    /prop_tgt/NO_SONAME

Help/prop_tgt/MANUALLY_ADDED_DEPENDENCIES.rst

@@ -0,0 +1,8 @@
+MANUALLY_ADDED_DEPENDENCIES
+---------------------------
+
+Get manually added dependencies to other top-level targets.
+
+This read-only property can be used to query all dependencies that
+were added for this target with the :command:`add_dependencies`
+command.

Help/release/dev/manually-added-dependencies.rst

@@ -0,0 +1,6 @@
+manually-added-dependencies
+---------------------------
+
+* The target property :prop_tgt:`MANUALLY_ADDED_DEPENDENCIES` has
+  been added.  It is read-only and could be used to retrieve
+  dependencies that have been added with :command:`add_dependencies`.

Source/cmTarget.cxx

@@ -852,6 +852,12 @@ void cmTarget::SetProperty(const std::string& prop, const char* value)
         this->Makefile->GetBacktrace())) {
     return;
   }
+  if (prop == "MANUALLY_ADDED_DEPENDENCIES") {
+    std::ostringstream e;
+    e << "MANUALLY_ADDED_DEPENDENCIES property is read-only\n";
+    this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
+    return;
+  }
   if (prop == "NAME") {
     std::ostringstream e;
     e << "NAME property is read-only\n";
@@ -1168,6 +1174,7 @@ const char* cmTarget::GetProperty(const std::string& prop) const
   MAKE_STATIC_PROP(COMPILE_OPTIONS);
   MAKE_STATIC_PROP(COMPILE_DEFINITIONS);
   MAKE_STATIC_PROP(IMPORTED);
+  MAKE_STATIC_PROP(MANUALLY_ADDED_DEPENDENCIES);
   MAKE_STATIC_PROP(NAME);
   MAKE_STATIC_PROP(BINARY_DIR);
   MAKE_STATIC_PROP(SOURCE_DIR);
@@ -1181,6 +1188,7 @@ const char* cmTarget::GetProperty(const std::string& prop) const
     specialProps.insert(propCOMPILE_OPTIONS);
     specialProps.insert(propCOMPILE_DEFINITIONS);
     specialProps.insert(propIMPORTED);
+    specialProps.insert(propMANUALLY_ADDED_DEPENDENCIES);
     specialProps.insert(propNAME);
     specialProps.insert(propBINARY_DIR);
     specialProps.insert(propSOURCE_DIR);
@@ -1236,6 +1244,15 @@ const char* cmTarget::GetProperty(const std::string& prop) const
       output = cmJoin(this->Internal->CompileDefinitionsEntries, ";");
       return output.c_str();
     }
+    if (prop == propMANUALLY_ADDED_DEPENDENCIES) {
+      if (this->Utilities.empty()) {
+        return CM_NULLPTR;
+      }
+
+      static std::string output;
+      output = cmJoin(this->Utilities, ";");
+      return output.c_str();
+    }
     if (prop == propIMPORTED) {
       return this->IsImported() ? "TRUE" : "FALSE";
     }

Tests/RunCMake/add_dependencies/ReadOnlyProperty-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/add_dependencies/ReadOnlyProperty-stderr.txt

@@ -0,0 +1 @@
+MANUALLY_ADDED_DEPENDENCIES property is read-only

Tests/RunCMake/add_dependencies/ReadOnlyProperty.cmake

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.7)
+project(ReadOnlyProperty C)
+
+add_library(a a.c)
+
+set_property(TARGET a PROPERTY MANUALLY_ADDED_DEPENDENCIES DEPENDENCIES foo)

Tests/RunCMake/add_dependencies/RetrieveDependencies.cmake

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.7)
+project(RetrieveDependencies C)
+
+add_library(a a.c)
+
+add_library(b c.c)
+target_link_libraries(a b)
+
+add_library(c c.c)
+add_dependencies(a c)
+
+get_property(DEPS_A TARGET a PROPERTY MANUALLY_ADDED_DEPENDENCIES)
+
+if(NOT DEPS_A STREQUAL "c")
+  message(FATAL_ERROR "Expected target c being a dependency of a but got: '${DEPS_A}'")
+endif()

Tests/RunCMake/add_dependencies/RunCMakeTest.cmake

@@ -1,3 +1,5 @@
 include(RunCMake)
 
 run_cmake(NoTarget)
+run_cmake(ReadOnlyProperty)
+run_cmake(RetrieveDependencies)

Tests/RunCMake/add_dependencies/a.c

@@ -0,0 +1,3 @@
+void a()
+{
+}

Tests/RunCMake/add_dependencies/b.c

@@ -0,0 +1,3 @@
+void b()
+{
+}

Tests/RunCMake/add_dependencies/c.c

@@ -0,0 +1,3 @@
+void c()
+{
+}