UseSWIG: add policy to manage target naming strategy.

25 files changed, 107 insertions, 28 deletions

diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst
index b2eeb3a8a1..32a0118687 100644
--- a/Help/manual/cmake-policies.7.rst
+++ b/Help/manual/cmake-policies.7.rst
@@ -57,6 +57,7 @@ Policies Introduced by CMake 3.13
 .. toctree::
    :maxdepth: 1
 
+   CMP0078: UseSWIG generates standard target names. </policy/CMP0078>
    CMP0077: option() honors normal variables. </policy/CMP0077>
    CMP0076: target_sources() command converts relative paths to absolute. </policy/CMP0076>
 
diff --git a/Help/policy/CMP0078.rst b/Help/policy/CMP0078.rst
new file mode 100644
index 0000000000..54cdc9cc7f
--- /dev/null
+++ b/Help/policy/CMP0078.rst
@@ -0,0 +1,22 @@
+CMP0078
+-------
+
+Starting with CMake 3.13, :module:`UseSWIG` generates now standard target
+names. This policy provides compatibility with projects that expect the legacy
+behavior.
+
+The ``OLD`` behavior for this policy relies on
+``UseSWIG_TARGET_NAME_PREFERENCE`` variable that can be used to specify an
+explicit preference.  The value may be one of:
+
+* ``LEGACY``: legacy strategy is applied. Variable
+  ``SWIG_MODULE_<name>_REAL_NAME`` must be used to get real target name.
+  This is the default if not specified.
+* ``STANDARD``: target name matches specified name.
+
+This policy was introduced in CMake version 3.13.  CMake version
+|release| warns when the policy is not set and uses ``OLD`` behavior.
+Use the :command:`cmake_policy` command to set it to ``OLD`` or ``NEW``
+explicitly.
+
+.. include:: DEPRECATED.txt
diff --git a/Help/release/dev/UseSWIG-target-name-policy.rst b/Help/release/dev/UseSWIG-target-name-policy.rst
new file mode 100644
index 0000000000..bb9011d777
--- /dev/null
+++ b/Help/release/dev/UseSWIG-target-name-policy.rst
@@ -0,0 +1,5 @@
+UseSWIG-target-name-policy
+--------------------------
+
+* The :module:`UseSWIG` module has changed strategy for target naming.
+  See policy :policy:`CMP0078`.
diff --git a/Modules/UseSWIG.cmake b/Modules/UseSWIG.cmake
index 7460932885..e7aaf32eef 100644
--- a/Modules/UseSWIG.cmake
+++ b/Modules/UseSWIG.cmake
@@ -30,9 +30,10 @@ Defines the following command for use with ``SWIG``:
 
   .. note::
 
-    The variable ``SWIG_MODULE_<name>_REAL_NAME`` will be set to the name
-    of the swig module target library. This variable is useless if variable
-    ``UseSWIG_TARGET_NAME_PREFERENCE`` is set to ``STANDARD``.
+    This command creates a target with the specified ``<name>`` when
+    policy :policy:`CMP0078` is set to ``NEW``.  Otherwise, the legacy
+    behavior will choose a different target name and store it in the
+    ``SWIG_MODULE_<name>_REAL_NAME`` variable.
 
   .. note::
 
@@ -197,13 +198,6 @@ information about support files generated by ``SWIG`` interface compilation.
 Some variables can be set to customize the behavior of ``swig_add_library``
 as well as ``SWIG``:
 
-``UseSWIG_TARGET_NAME_PREFERENCE``
-  Specify target name strategy.
-
-  * Set to ``LEGACY`` or undefined: legacy strategy is applied. Variable
-    ``SWIG_MODULE_<name>_REAL_NAME`` must be used to get real target name.
-  * Set to ``STANDARD``: target name matches specified name.
-
 ``UseSWIG_MODULE_VERSION``
   Specify different behaviors for ``UseSWIG`` module.
 
@@ -225,8 +219,13 @@ as well as ``SWIG``:
   Specify extra dependencies for the generated module for ``<name>``.
 #]=======================================================================]
 
-
+cmake_policy(GET CMP0078 target_name_policy)
 cmake_policy (VERSION 3.12)
+if (target_name_policy)
+  # respect user choice regarding CMP0078 policy
+  cmake_policy(SET CMP0078 ${target_name_policy})
+endif()
+unset(target_name_policy)
 
 set(SWIG_CXX_EXTENSION "cxx")
 set(SWIG_EXTRA_LIBRARIES "")
@@ -545,10 +544,22 @@ function(SWIG_ADD_LIBRARY name)
     unset(_SAM_TYPE)
   endif()
 
-  if (NOT DEFINED UseSWIG_TARGET_NAME_PREFERENCE)
-    set (UseSWIG_TARGET_NAME_PREFERENCE LEGACY)
-  elseif (NOT UseSWIG_TARGET_NAME_PREFERENCE MATCHES "^(LEGACY|STANDARD)$")
-    message (FATAL_ERROR "UseSWIG_TARGET_NAME_PREFERENCE: ${UseSWIG_TARGET_NAME_PREFERENCE}: invalid value. 'LEGACY' or 'STANDARD' is expected.")
+  cmake_policy(GET CMP0078 target_name_policy)
+  if (target_name_policy STREQUAL "NEW")
+    set (UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
+  else()
+    if (NOT target_name_policy)
+      message(AUTHOR_WARNING
+        "Policy CMP0078 is not set.  "
+        "Run \"cmake --help-policy CMP0078\" for policy details.  "
+        "Use the cmake_policy command to set the policy and suppress this warning."
+        )
+    endif()
+    if (NOT DEFINED UseSWIG_TARGET_NAME_PREFERENCE)
+      set (UseSWIG_TARGET_NAME_PREFERENCE LEGACY)
+    elseif (NOT UseSWIG_TARGET_NAME_PREFERENCE MATCHES "^(LEGACY|STANDARD)$")
+      message (FATAL_ERROR "UseSWIG_TARGET_NAME_PREFERENCE: ${UseSWIG_TARGET_NAME_PREFERENCE}: invalid value. 'LEGACY' or 'STANDARD' is expected.")
+    endif()
   endif()
 
   if (NOT DEFINED UseSWIG_MODULE_VERSION)
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index d6f7c54b91..91ed924ff4 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -228,7 +228,9 @@ class cmMakefile;
          "target_sources() command converts relative paths to absolute.", 3,  \
          13, 0, cmPolicies::WARN)                                             \
   SELECT(POLICY, CMP0077, "option() honors normal variables.", 3, 13, 0,      \
-         cmPolicies::WARN)
+         cmPolicies::WARN)                                                    \
+  SELECT(POLICY, CMP0078, "UseSWIG generates standard target names.", 3, 13,  \
+         0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index c030cda8a0..c6c90d0300 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -154,6 +154,9 @@ add_RunCMake_test(FPHSA)
 add_RunCMake_test(FindBoost)
 add_RunCMake_test(FindLua)
 add_RunCMake_test(FindOpenGL)
+if(CMake_TEST_UseSWIG)
+  add_RunCMake_test(UseSWIG)
+endif()
 if(NOT CMAKE_C_COMPILER_ID MATCHES "Watcom")
   add_RunCMake_test(GenerateExportHeader)
 endif()
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-NEW-stdout.txt b/Tests/RunCMake/UseSWIG/CMP0078-NEW-stdout.txt
new file mode 100644
index 0000000000..d4fa6e4b8a
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-NEW-stdout.txt
@@ -0,0 +1,2 @@
+-- PREFIX='_'
+-- TARGET NAME='example'
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-NEW.cmake b/Tests/RunCMake/UseSWIG/CMP0078-NEW.cmake
new file mode 100644
index 0000000000..ce77218c8f
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-NEW.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0078 NEW)
+include(CMP0078-common.cmake)
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-OLD-stdout.txt b/Tests/RunCMake/UseSWIG/CMP0078-OLD-stdout.txt
new file mode 100644
index 0000000000..62f5371e1a
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-OLD-stdout.txt
@@ -0,0 +1,2 @@
+-- PREFIX=''
+-- TARGET NAME='_example'
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-OLD.cmake b/Tests/RunCMake/UseSWIG/CMP0078-OLD.cmake
new file mode 100644
index 0000000000..2c4d142d5c
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-OLD.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0078 OLD)
+include(CMP0078-common.cmake)
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-WARN-stderr.txt b/Tests/RunCMake/UseSWIG/CMP0078-WARN-stderr.txt
new file mode 100644
index 0000000000..bc8da4c290
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-WARN-stderr.txt
@@ -0,0 +1,9 @@
+CMake Warning \(dev\) at .*/Modules/UseSWIG.cmake:[0-9]+ \(message\):
+  Policy CMP0078 is not set.  Run "cmake --help-policy CMP0078" for policy
+  details.  Use the cmake_policy command to set the policy and suppress this
+  warning.
+Call Stack \(most recent call first\):
+  CMP0078-common.cmake:6 \(swig_add_library\)
+  CMP0078-WARN.cmake:1 \(include\)
+  CMakeLists.txt:3 \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.$
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-WARN-stdout.txt b/Tests/RunCMake/UseSWIG/CMP0078-WARN-stdout.txt
new file mode 100644
index 0000000000..62f5371e1a
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-WARN-stdout.txt
@@ -0,0 +1,2 @@
+-- PREFIX=''
+-- TARGET NAME='_example'
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-WARN.cmake b/Tests/RunCMake/UseSWIG/CMP0078-WARN.cmake
new file mode 100644
index 0000000000..86b21a5859
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-WARN.cmake
@@ -0,0 +1 @@
+include(CMP0078-common.cmake)
diff --git a/Tests/RunCMake/UseSWIG/CMP0078-common.cmake b/Tests/RunCMake/UseSWIG/CMP0078-common.cmake
new file mode 100644
index 0000000000..6cf39dcf86
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMP0078-common.cmake
@@ -0,0 +1,10 @@
+
+set(SWIG_EXECUTABLE "swig")
+set(SWIG_DIR "/swig")
+include(UseSWIG)
+
+swig_add_library(example LANGUAGE python TYPE MODULE SOURCES example.i)
+
+get_property(prefix TARGET ${SWIG_MODULE_example_REAL_NAME} PROPERTY PREFIX)
+message(STATUS "PREFIX='${prefix}'")
+message(STATUS "TARGET NAME='${SWIG_MODULE_example_REAL_NAME}'")
diff --git a/Tests/RunCMake/UseSWIG/CMakeLists.txt b/Tests/RunCMake/UseSWIG/CMakeLists.txt
new file mode 100644
index 0000000000..d1b0d2c3e8
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.10)
+project(${RunCMake_TEST} C)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/UseSWIG/RunCMakeTest.cmake b/Tests/RunCMake/UseSWIG/RunCMakeTest.cmake
new file mode 100644
index 0000000000..b96622ae32
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/RunCMakeTest.cmake
@@ -0,0 +1,5 @@
+include(RunCMake)
+
+run_cmake(CMP0078-WARN)
+run_cmake(CMP0078-OLD)
+run_cmake(CMP0078-NEW)
diff --git a/Tests/RunCMake/UseSWIG/example.i b/Tests/RunCMake/UseSWIG/example.i
new file mode 100644
index 0000000000..86625aa3a2
--- /dev/null
+++ b/Tests/RunCMake/UseSWIG/example.i
@@ -0,0 +1,2 @@
+/* File : example.i */
+%module example
diff --git a/Tests/UseSWIG/BasicConfiguration.cmake b/Tests/UseSWIG/BasicConfiguration.cmake
index ad34d39093..fd3ac4031d 100644
--- a/Tests/UseSWIG/BasicConfiguration.cmake
+++ b/Tests/UseSWIG/BasicConfiguration.cmake
@@ -58,7 +58,6 @@ if(${language} MATCHES lua)
   set(SWIG_LANG_LIBRARIES ${LUA_LIBRARIES})
 endif()
 
-set(UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
 unset(CMAKE_SWIG_FLAGS)
 
 set (CMAKE_INCLUDE_CURRENT_DIR ON)
diff --git a/Tests/UseSWIG/BasicCsharp/CMakeLists.txt b/Tests/UseSWIG/BasicCsharp/CMakeLists.txt
index 84743efa03..1a6c763b56 100644
--- a/Tests/UseSWIG/BasicCsharp/CMakeLists.txt
+++ b/Tests/UseSWIG/BasicCsharp/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.12)
+cmake_minimum_required(VERSION 3.12...3.13)
 
 project(TestBasicCsharp CXX CSharp)
 
diff --git a/Tests/UseSWIG/BasicPerl/CMakeLists.txt b/Tests/UseSWIG/BasicPerl/CMakeLists.txt
index 476ef0e9a5..cf02de7de6 100644
--- a/Tests/UseSWIG/BasicPerl/CMakeLists.txt
+++ b/Tests/UseSWIG/BasicPerl/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestBasicPerl CXX)
 
diff --git a/Tests/UseSWIG/BasicPython/CMakeLists.txt b/Tests/UseSWIG/BasicPython/CMakeLists.txt
index cf1d8213c7..8bbd1cbe83 100644
--- a/Tests/UseSWIG/BasicPython/CMakeLists.txt
+++ b/Tests/UseSWIG/BasicPython/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestBasicPython CXX)
 
diff --git a/Tests/UseSWIG/ModuleVersion2/CMakeLists.txt b/Tests/UseSWIG/ModuleVersion2/CMakeLists.txt
index 452f9e2738..a7ee2106ba 100644
--- a/Tests/UseSWIG/ModuleVersion2/CMakeLists.txt
+++ b/Tests/UseSWIG/ModuleVersion2/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestModuleVersion2 CXX)
 
@@ -16,7 +16,6 @@ else()
   set (PS ":")
 endif()
 
-set(UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
 set (UseSWIG_MODULE_VERSION 2)
 unset(CMAKE_SWIG_FLAGS)
 
diff --git a/Tests/UseSWIG/MultipleModules/CMakeLists.txt b/Tests/UseSWIG/MultipleModules/CMakeLists.txt
index 25dd6b317d..f1dc379c56 100644
--- a/Tests/UseSWIG/MultipleModules/CMakeLists.txt
+++ b/Tests/UseSWIG/MultipleModules/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestMultipleModules CXX)
 
@@ -19,7 +19,6 @@ else()
   set (PS ":")
 endif()
 
-set(UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
 unset(CMAKE_SWIG_FLAGS)
 
 set_property(SOURCE "../example.i" PROPERTY CPLUSPLUS ON)
diff --git a/Tests/UseSWIG/MultiplePython/CMakeLists.txt b/Tests/UseSWIG/MultiplePython/CMakeLists.txt
index a1651fbfef..8f87755766 100644
--- a/Tests/UseSWIG/MultiplePython/CMakeLists.txt
+++ b/Tests/UseSWIG/MultiplePython/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestMultiplePython CXX)
 
@@ -17,7 +17,6 @@ else()
   set (PS ":")
 endif()
 
-set(UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
 unset(CMAKE_SWIG_FLAGS)
 
 set_property(SOURCE "../example.i" PROPERTY CPLUSPLUS ON)
diff --git a/Tests/UseSWIG/UseTargetINCLUDE_DIRECTORIES/CMakeLists.txt b/Tests/UseSWIG/UseTargetINCLUDE_DIRECTORIES/CMakeLists.txt
index d0855bfb88..fbb72d5715 100644
--- a/Tests/UseSWIG/UseTargetINCLUDE_DIRECTORIES/CMakeLists.txt
+++ b/Tests/UseSWIG/UseTargetINCLUDE_DIRECTORIES/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.1...3.13)
 
 project(TestUseTargetINCLUDE_DIRECTORIES CXX)
 
@@ -9,7 +9,6 @@ include(${SWIG_USE_FILE})
 
 find_package(Python3 REQUIRED COMPONENTS Interpreter Development)
 
-set(UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
 unset(CMAKE_SWIG_FLAGS)
 
 set_property(SOURCE "example.i" PROPERTY CPLUSPLUS ON)