Merge topic 'imported-interface-no-system'

22beb07f Help: Clarify documentation of NO_SYSTEM_FROM_IMPORTED
2de0e0fd Do not initialize NO_SYSTEM_FROM_IMPORTED on INTERFACE libraries

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1386

5 files changed, 22 insertions, 15 deletions

diff --git a/Help/manual/cmake-buildsystem.7.rst b/Help/manual/cmake-buildsystem.7.rst
index debaf23..ae538ed 100644
--- a/Help/manual/cmake-buildsystem.7.rst
+++ b/Help/manual/cmake-buildsystem.7.rst
@@ -687,7 +687,8 @@ property are treated as ``SYSTEM`` include directories, as if they were
 listed in the :prop_tgt:`INTERFACE_SYSTEM_INCLUDE_DIRECTORIES` of the
 dependency. This can result in omission of compiler warnings for headers
 found in those directories.  This behavior for :ref:`imported targets` may
-be controlled with the :prop_tgt:`NO_SYSTEM_FROM_IMPORTED` target property.
+be controlled by setting the :prop_tgt:`NO_SYSTEM_FROM_IMPORTED` target
+property on the *consumers* of imported targets.
 
 If a binary target is linked transitively to a Mac OX framework, the
 ``Headers`` directory of the framework is also treated as a usage requirement.
@@ -970,7 +971,6 @@ are:
 * ``EXPORT_NAME``
 * ``IMPORTED``
 * ``NAME``
-* ``NO_SYSTEM_FROM_IMPORTED``
 * Properties matching ``IMPORTED_LIBNAME_*``
 * Properties matching ``MAP_IMPORTED_CONFIG_*``
 
diff --git a/Help/prop_tgt/NO_SYSTEM_FROM_IMPORTED.rst b/Help/prop_tgt/NO_SYSTEM_FROM_IMPORTED.rst
index 070dd30..880343d 100644
--- a/Help/prop_tgt/NO_SYSTEM_FROM_IMPORTED.rst
+++ b/Help/prop_tgt/NO_SYSTEM_FROM_IMPORTED.rst
@@ -1,11 +1,15 @@
 NO_SYSTEM_FROM_IMPORTED
 -----------------------
 
-Do not treat includes from IMPORTED target interfaces as SYSTEM.
+Do not treat include directories from the interfaces of consumed
+:ref:`imported targets` as ``SYSTEM``.
 
-The contents of the INTERFACE_INCLUDE_DIRECTORIES of IMPORTED targets
-are treated as SYSTEM includes by default.  If this property is
-enabled, the contents of the INTERFACE_INCLUDE_DIRECTORIES of IMPORTED
-targets are not treated as system includes.  This property is
-initialized by the value of the variable CMAKE_NO_SYSTEM_FROM_IMPORTED
-if it is set when a target is created.
+The contents of the :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` target property
+of imported targets are treated as ``SYSTEM`` includes by default.  If this
+property is enabled on a target, compilation of sources in that target will
+not treat the contents of the ``INTERFACE_INCLUDE_DIRECTORIES`` of consumed
+imported targets as system includes.
+
+This property is initialized by the value of the
+:variable:`CMAKE_NO_SYSTEM_FROM_IMPORTED` variable if it is set when a target
+is created.
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 7a3cc76..c6cd502 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -256,6 +256,7 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     this->SetPropertyDefault("WIN32_EXECUTABLE", nullptr);
     this->SetPropertyDefault("MACOSX_BUNDLE", nullptr);
     this->SetPropertyDefault("MACOSX_RPATH", nullptr);
+    this->SetPropertyDefault("NO_SYSTEM_FROM_IMPORTED", nullptr);
     this->SetPropertyDefault("BUILD_WITH_INSTALL_NAME_DIR", nullptr);
     this->SetPropertyDefault("C_CLANG_TIDY", nullptr);
     this->SetPropertyDefault("C_COMPILER_LAUNCHER", nullptr);
@@ -282,10 +283,6 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     this->SetPropertyDefault("LINK_SEARCH_END_STATIC", nullptr);
   }
 
-  if (this->GetType() != cmStateEnums::UTILITY) {
-    this->SetPropertyDefault("NO_SYSTEM_FROM_IMPORTED", nullptr);
-  }
-
   // Collect the set of configuration types.
   std::vector<std::string> configNames;
   mf->GetConfigurations(configNames);
diff --git a/Source/cmTargetPropertyComputer.cxx b/Source/cmTargetPropertyComputer.cxx
index 3a3c165..1d2520d 100644
--- a/Source/cmTargetPropertyComputer.cxx
+++ b/Source/cmTargetPropertyComputer.cxx
@@ -66,12 +66,19 @@ bool cmTargetPropertyComputer::WhiteListedInterfaceProperty(
   }
 
   if (prop == "IMPORTED_CONFIGURATIONS" || prop == "IMPORTED_LIBNAME" ||
-      prop == "NO_SYSTEM_FROM_IMPORTED" ||
       cmHasLiteralPrefix(prop, "IMPORTED_LIBNAME_") ||
       cmHasLiteralPrefix(prop, "MAP_IMPORTED_CONFIG_")) {
     return true;
   }
 
+  // This property should not be allowed but was incorrectly added in
+  // CMake 3.8.  We can't remove it from the whitelist without breaking
+  // projects that try to set it.  One day we could warn about this, but
+  // for now silently accept it.
+  if (prop == "NO_SYSTEM_FROM_IMPORTED") {
+    return true;
+  }
+
   return false;
 }
 
diff --git a/Tests/InterfaceLibrary/CMakeLists.txt b/Tests/InterfaceLibrary/CMakeLists.txt
index 33c4b90..3db210a 100644
--- a/Tests/InterfaceLibrary/CMakeLists.txt
+++ b/Tests/InterfaceLibrary/CMakeLists.txt
@@ -64,7 +64,6 @@ target_link_libraries(iface_whitelist INTERFACE $<$<BOOL:$<TARGET_PROPERTY:CUSTO
 add_executable(exec_whitelist dummy.cpp)
 target_link_libraries(exec_whitelist iface_whitelist)
 
-set(CMAKE_NO_SYSTEM_FROM_IMPORTED 1)
 add_library(iface_imported INTERFACE IMPORTED)
 set_property(TARGET iface_imported PROPERTY
   INTERFACE_COMPILE_DEFINITIONS