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.

1 files changed, 11 insertions, 0 deletions

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 \(include\)