cmTarget: Deprecate the LOCATION target property with a policy.

The final location and name of a build-target is not determined
until generate-time. However, reading the LOCATION property from
a target is currently allowed at configure time. Apart from creating
possibly-erroneous results, this has an impact on the implementation
of cmake itself, and prevents some major cleanups from being made.

Disallow reading LOCATION from build-targets with a policy. Port some
existing uses of it in CMake itself to use the TARGET_FILE generator
expression.

15 files changed, 74 insertions, 3 deletions

diff --git a/Tests/FindPackageModeMakefileTest/CMakeLists.txt b/Tests/FindPackageModeMakefileTest/CMakeLists.txt
index 3674f0e..5d1b376 100644
--- a/Tests/FindPackageModeMakefileTest/CMakeLists.txt
+++ b/Tests/FindPackageModeMakefileTest/CMakeLists.txt
@@ -19,8 +19,16 @@ if(UNIX  AND  "${CMAKE_GENERATOR}" MATCHES "Makefile")
     configure_file(FindFoo.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/FindFoo.cmake @ONLY)
 
     # now set up the test:
-    get_target_property(cmakeExecutable cmake LOCATION)
-
+    if (NOT CMAKE_VERSION VERSION_LESS 2.8.12)
+      file(GENERATE OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/cmakeExecutable.mk"
+        CONTENT "CMAKE = \"$<TARGET_FILE:cmake>\"\n"
+      )
+    else()
+      get_target_property(cmakeLocation cmake LOCATION)
+      file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/cmakeExecutable.mk"
+        "CMAKE = \"${cmakeLocation}\"\n"
+      )
+    endif()
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Makefile.in ${CMAKE_CURRENT_BINARY_DIR}/ConfMakefile @ONLY)
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/main.cpp ${CMAKE_CURRENT_BINARY_DIR}/main.cpp COPYONLY)
 
diff --git a/Tests/FindPackageModeMakefileTest/Makefile.in b/Tests/FindPackageModeMakefileTest/Makefile.in
index f647901..c91d8a0 100644
--- a/Tests/FindPackageModeMakefileTest/Makefile.in
+++ b/Tests/FindPackageModeMakefileTest/Makefile.in
@@ -1,4 +1,6 @@
-CMAKE = "@cmakeExecutable@"
+
+include cmakeExecutable.mk
+
 CMAKE_CURRENT_BINARY_DIR = "@CMAKE_CURRENT_BINARY_DIR@"
 CMAKE_CXX_COMPILER = "@CMAKE_CXX_COMPILER@"
 CMAKE_CXX_COMPILER_ID = "@CMAKE_CXX_COMPILER_ID@"
diff --git a/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-result.txt b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-result.txt
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-result.txt
@@ -0,0 +1 @@
+0
diff --git a/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-stderr.txt b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-stderr.txt
new file mode 100644
index 0000000..10f3293
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED-stderr.txt
@@ -0,0 +1 @@
+^$
diff --git a/Tests/RunCMake/CMP0026/CMP0026-IMPORTED.cmake b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED.cmake
new file mode 100644
index 0000000..650c8a5
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-IMPORTED.cmake
@@ -0,0 +1,6 @@
+
+enable_language(CXX)
+
+add_library(someimportedlib SHARED IMPORTED)
+
+get_target_property(_loc someimportedlib LOCATION)
diff --git a/Tests/RunCMake/CMP0026/CMP0026-NEW-result.txt b/Tests/RunCMake/CMP0026/CMP0026-NEW-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-NEW-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/CMP0026/CMP0026-NEW-stderr.txt b/Tests/RunCMake/CMP0026/CMP0026-NEW-stderr.txt
new file mode 100644
index 0000000..2a05a4d
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-NEW-stderr.txt
@@ -0,0 +1,11 @@
+CMake Error at CMP0026-NEW.cmake:7 \(get_target_property\):
+  Policy CMP0026 is not set: Disallow use of the LOCATION target property.
+  Run "cmake --help-policy CMP0026" for policy details.  Use the cmake_policy
+  command to set the policy and suppress this warning.
+
+  The LOCATION property may not be read from target "somelib".  Use the
+  target name directly with add_custom_command, or use the generator
+  expression \$<TARGET_FILE>, as appropriate.
+
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/CMP0026/CMP0026-NEW.cmake b/Tests/RunCMake/CMP0026/CMP0026-NEW.cmake
new file mode 100644
index 0000000..1659ffc
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-NEW.cmake
@@ -0,0 +1,7 @@
+
+enable_language(CXX)
+
+cmake_policy(SET CMP0026 NEW)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib LOCATION)
diff --git a/Tests/RunCMake/CMP0026/CMP0026-WARN-result.txt b/Tests/RunCMake/CMP0026/CMP0026-WARN-result.txt
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-WARN-result.txt
@@ -0,0 +1 @@
+0
diff --git a/Tests/RunCMake/CMP0026/CMP0026-WARN-stderr.txt b/Tests/RunCMake/CMP0026/CMP0026-WARN-stderr.txt
new file mode 100644
index 0000000..9b88194
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-WARN-stderr.txt
@@ -0,0 +1,12 @@
+CMake Warning \(dev\) at CMP0026-WARN.cmake:5 \(get_target_property\):
+  Policy CMP0026 is not set: Disallow use of the LOCATION target property.
+  Run "cmake --help-policy CMP0026" for policy details.  Use the cmake_policy
+  command to set the policy and suppress this warning.
+
+  The LOCATION property should not be read from target "somelib".  Use the
+  target name directly with add_custom_command, or use the generator
+  expression \$<TARGET_FILE>, as appropriate.
+
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.
diff --git a/Tests/RunCMake/CMP0026/CMP0026-WARN.cmake b/Tests/RunCMake/CMP0026/CMP0026-WARN.cmake
new file mode 100644
index 0000000..89c5a8a
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMP0026-WARN.cmake
@@ -0,0 +1,5 @@
+
+enable_language(CXX)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib LOCATION)
diff --git a/Tests/RunCMake/CMP0026/CMakeLists.txt b/Tests/RunCMake/CMP0026/CMakeLists.txt
new file mode 100644
index 0000000..e8db6b0
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 2.8)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/CMP0026/RunCMakeTest.cmake b/Tests/RunCMake/CMP0026/RunCMakeTest.cmake
new file mode 100644
index 0000000..68000a6
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/RunCMakeTest.cmake
@@ -0,0 +1,5 @@
+include(RunCMake)
+
+run_cmake(CMP0026-WARN)
+run_cmake(CMP0026-NEW)
+run_cmake(CMP0026-IMPORTED)
diff --git a/Tests/RunCMake/CMP0026/empty.cpp b/Tests/RunCMake/CMP0026/empty.cpp
new file mode 100644
index 0000000..bfbbdde
--- /dev/null
+++ b/Tests/RunCMake/CMP0026/empty.cpp
@@ -0,0 +1,7 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int empty()
+{
+  return 0;
+}
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 4fbc3b0..6d5b07b 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -53,6 +53,7 @@ endif()
 
 add_RunCMake_test(CMP0019)
 add_RunCMake_test(CMP0022)
+add_RunCMake_test(CMP0026)
 add_RunCMake_test(CTest)
 if(UNIX AND "${CMAKE_TEST_GENERATOR}" MATCHES "Unix Makefiles")
   add_RunCMake_test(CompilerChange)