Merge topic 'add_dependencies-INTERFACE-libraries'

ac14cbf0 Allow add_dependencies() on INTERFACE libraries (#15414)
817d31db Help: Format add_dependencies documentation

Help/command/add_dependencies.rst

@@ -7,13 +7,16 @@ Add a dependency between top-level targets.
 
   add_dependencies(<target> [<target-dependency>]...)
 
-Make a top-level <target> depend on other top-level targets to ensure
-that they build before <target> does.  A top-level target is one
-created by ADD_EXECUTABLE, ADD_LIBRARY, or ADD_CUSTOM_TARGET.
-Dependencies added to an IMPORTED target are followed transitively in
-its place since the target itself does not build.
+Make a top-level ``<target>`` depend on other top-level targets to
+ensure that they build before ``<target>`` does.  A top-level target
+is one created by one of the :command:`add_executable`,
+:command:`add_library`, or :command:`add_custom_target` commands.
 
-See the DEPENDS option of ADD_CUSTOM_TARGET and ADD_CUSTOM_COMMAND for
-adding file-level dependencies in custom rules.  See the
-OBJECT_DEPENDS option in SET_SOURCE_FILES_PROPERTIES to add file-level
-dependencies to object files.
+Dependencies added to an :ref:`imported target <Imported Targets>`
+or an :ref:`interface library <Interface Libraries>` are followed
+transitively in its place since the target itself does not build.
+
+See the ``DEPENDS`` option of :command:`add_custom_target` and
+:command:`add_custom_command` commands for adding file-level
+dependencies in custom rules.  See the :prop_sf:`OBJECT_DEPENDS`
+source file property to add file-level dependencies to object files.

Help/release/dev/add_dependencies-INTERFACE-libraries.rst

@@ -0,0 +1,7 @@
+add_dependencies-INTERFACE-libraries
+------------------------------------
+
+* The :command:`add_dependencies` command learned to allow dependencies
+  to be added to :ref:`interface libraries <Interface Libraries>`.
+  Dependencies added to an interface library are followed transitively
+  in its place since the target itself does not build.

Source/cmAddDependenciesCommand.cxx

@@ -33,15 +33,6 @@ bool cmAddDependenciesCommand
     }
   if(cmTarget* target = this->Makefile->FindTargetToUse(target_name))
     {
-    if (target->GetType() == cmTarget::INTERFACE_LIBRARY)
-      {
-      std::ostringstream e;
-      e << "Cannot add target-level dependencies to INTERFACE library "
-        "target \"" << target_name << "\".\n";
-      this->SetError(e.str());
-      return false;
-      }
-
     std::vector<std::string>::const_iterator s = args.begin();
     ++s; // skip over target_name
     for (; s != args.end(); ++s)

Source/cmComputeTargetDepends.cxx

@@ -418,9 +418,11 @@ void cmComputeTargetDepends::AddTargetDepend(int depender_index,
                                              cmTarget const* dependee,
                                              bool linking)
 {
-  if(dependee->IsImported())
+  if(dependee->IsImported() ||
+     dependee->GetType() == cmTarget::INTERFACE_LIBRARY)
     {
-    // Skip imported targets but follow their utility dependencies.
+    // Skip IMPORTED and INTERFACE targets but follow their utility
+    // dependencies.
     std::set<cmLinkItem> const& utils = dependee->GetUtilityItems();
     for(std::set<cmLinkItem>::const_iterator i = utils.begin();
         i != utils.end(); ++i)

Tests/InterfaceLibrary/headerdir/CMakeLists.txt

@@ -3,6 +3,11 @@ set(CMAKE_INCLUDE_CURRENT_DIR_IN_INTERFACE ON)
 
 add_library(headeriface INTERFACE)
 
-file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/iface_header_builddir.h"
-  "#define IFACE_HEADER_BUILDDIR\n"
-)
+add_custom_target(headeriface_gen
+  COMMENT "Generating iface_header_builddir.h"
+  COMMAND ${CMAKE_COMMAND} -E copy_if_different
+    ${CMAKE_CURRENT_SOURCE_DIR}/iface_header_builddir.h.in
+    ${CMAKE_CURRENT_BINARY_DIR}/iface_header_builddir.h
+  VERBATIM
+  )
+add_dependencies(headeriface headeriface_gen)

Tests/InterfaceLibrary/headerdir/iface_header_builddir.h.in

@@ -0,0 +1 @@
+#define IFACE_HEADER_BUILDDIR

Tests/RunCMake/interface_library/RunCMakeTest.cmake

@@ -7,5 +7,4 @@ run_cmake(whitelist)
 run_cmake(invalid_signature)
 run_cmake(global-interface)
 run_cmake(genex_link)
-run_cmake(add_dependencies)
 run_cmake(add_custom_command-TARGET)

Tests/RunCMake/interface_library/add_dependencies-result.txt

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

Tests/RunCMake/interface_library/add_dependencies-stderr.txt

@@ -1,6 +0,0 @@
-CMake Error at add_dependencies.cmake:4 \(add_dependencies\):
-  add_dependencies Cannot add target-level dependencies to INTERFACE library
-  target "iface".
-
-Call Stack \(most recent call first\):
-  CMakeLists.txt:3 \(include\)

Tests/RunCMake/interface_library/add_dependencies.cmake

@@ -1,4 +0,0 @@
-
-add_library(foo empty.cpp)
-add_library(iface INTERFACE)
-add_dependencies(iface foo)