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Diffstat (limited to 'Help/policy/CMP0102.rst')
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diff --git a/Help/policy/CMP0102.rst b/Help/policy/CMP0102.rst new file mode 100644 index 0000000..9859006 --- /dev/null +++ b/Help/policy/CMP0102.rst @@ -0,0 +1,25 @@ +CMP0102 +------- + +The :command:`mark_as_advanced` command no longer creates a cache entry if one +does not already exist. + +In CMake 3.16 and below, if a variable was not defined at all or just defined +locally, the :command:`mark_as_advanced` command would create a new cache +entry with an ``UNINITIALIZED`` type and no value. When a :command:`find_path` +(or other similar ``find_`` command) would next run, it would find this +undefined cache entry and set it up with an empty string value. This process +would end up deleting the local variable in the process (due to the way the +cache works), effectively clearing any stored ``find_`` results that were only +available in the local scope. + +The ``OLD`` behavior for this policy is to create the empty cache definition. +The ``NEW`` behavior of this policy is to ignore variables which do not +already exist in the cache. + +This policy was introduced in CMake version 3.17. Use the +:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly. +Unlike many policies, CMake version |release| does *not* warn +when this policy is not set and simply uses ``OLD`` behavior. + +.. include:: DEPRECATED.txt |