cmTarget: Restore <CONFIG>_LOCATION to CMP0026 OLD behavior (#14808)

Restore support for the undocumented <CONFIG>_LOCATION target property
removed by commit v3.0.0-rc1~175^2 (cmTarget: Remove support for
<CONFIG>_LOCATION property, 2013-12-30) as part of the CMP0026 OLD
behavior.

Help/policy/CMP0026.rst

@@ -3,7 +3,8 @@ CMP0026
 
 Disallow use of the LOCATION target property.
 
-CMake 2.8.12 and lower allowed reading the LOCATION target property to
+CMake 2.8.12 and lower allowed reading the LOCATION target
+property (and configuration-specific variants) to
 determine the eventual location of build targets.  This relies on the
 assumption that all necessary information is available at
 configure-time to determine the final location and filename of the
@@ -17,8 +18,8 @@ $<TARGET_FILE> generator expression together with the file(GENERATE)
 subcommand to generate a file containing the target location.
 
 The OLD behavior for this policy is to allow reading the LOCATION
-property from build-targets.  The NEW behavior for this policy is to
+properties from build-targets.  The NEW behavior for this policy is to
-not to allow reading the LOCATION property from build-targets.
+not to allow reading the LOCATION properties from build-targets.
 
 This policy was introduced in CMake version 3.0.  CMake version
 |release| warns when the policy is not set and uses OLD behavior.  Use

Source/cmTarget.cxx

@@ -2730,6 +2730,21 @@ const char *cmTarget::GetProperty(const char* prop,
                                    this->GetLocation(configName.c_str()),
                                    cmProperty::TARGET);
       }
+    // Support "<CONFIG>_LOCATION".
+    if(cmHasLiteralSuffix(prop, "_LOCATION"))
+      {
+      std::string configName(prop, strlen(prop) - 9);
+      if(configName != "IMPORTED")
+        {
+        if (!this->HandleLocationPropertyPolicy())
+          {
+          return 0;
+          }
+        this->Properties.SetProperty(prop,
+                                     this->GetLocation(configName.c_str()),
+                                     cmProperty::TARGET);
+        }
+      }
     }
   if(strcmp(prop,"INCLUDE_DIRECTORIES") == 0)
     {

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-NEW-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-NEW-stderr.txt

@@ -0,0 +1,11 @@
+CMake Error at CMP0026-CONFIG-LOCATION-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 \(include\)

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-NEW.cmake

@@ -0,0 +1,7 @@
+
+enable_language(CXX)
+
+cmake_policy(SET CMP0026 NEW)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib Debug_LOCATION)

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-OLD-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-OLD-stderr.txt

@@ -0,0 +1 @@
+^$

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-OLD.cmake

@@ -0,0 +1,7 @@
+
+enable_language(CXX)
+
+cmake_policy(SET CMP0026 OLD)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib Debug_LOCATION)

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-WARN-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-WARN-stderr.txt

@@ -0,0 +1,12 @@
+CMake Warning \(dev\) at CMP0026-CONFIG-LOCATION-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.

Tests/RunCMake/CMP0026/CMP0026-CONFIG-LOCATION-WARN.cmake

@@ -0,0 +1,5 @@
+
+enable_language(CXX)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib Debug_LOCATION)

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-NEW-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-NEW-stderr.txt

@@ -0,0 +1,11 @@
+CMake Error at CMP0026-LOCATION-CONFIG-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 \(include\)

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-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_Debug)

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-OLD-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-OLD-stderr.txt

@@ -0,0 +1 @@
+^$

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-OLD.cmake

@@ -0,0 +1,7 @@
+
+enable_language(CXX)
+
+cmake_policy(SET CMP0026 OLD)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib LOCATION_Debug)

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-WARN-result.txt

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

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-WARN-stderr.txt

@@ -0,0 +1,12 @@
+CMake Warning \(dev\) at CMP0026-LOCATION-CONFIG-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.

Tests/RunCMake/CMP0026/CMP0026-LOCATION-CONFIG-WARN.cmake

@@ -0,0 +1,5 @@
+
+enable_language(CXX)
+
+add_library(somelib empty.cpp)
+get_target_property(_loc somelib LOCATION_Debug)

Tests/RunCMake/CMP0026/RunCMakeTest.cmake

@@ -3,3 +3,9 @@ include(RunCMake)
 run_cmake(CMP0026-WARN)
 run_cmake(CMP0026-NEW)
 run_cmake(CMP0026-IMPORTED)
+run_cmake(CMP0026-CONFIG-LOCATION-NEW)
+run_cmake(CMP0026-CONFIG-LOCATION-OLD)
+run_cmake(CMP0026-CONFIG-LOCATION-WARN)
+run_cmake(CMP0026-LOCATION-CONFIG-NEW)
+run_cmake(CMP0026-LOCATION-CONFIG-OLD)
+run_cmake(CMP0026-LOCATION-CONFIG-WARN)