GenEx: Remove unneeded dependencies from target info queries

Only generate a graph dependency between a custom command and
a target when the custom command queries for the file path
of an artifact of the target.

This makes generator expressions such as `TARGET_FILE_DIR`
behave the same way as `TARGET_PROPERTY` which never generated
a graph dependency.

1 files changed, 39 insertions, 0 deletions

diff --git a/Help/policy/CMP0112.rst b/Help/policy/CMP0112.rst
new file mode 100644
index 0000000..3eab6d2
--- /dev/null
+++ b/Help/policy/CMP0112.rst
@@ -0,0 +1,39 @@
+CMP0112
+-------
+
+.. versionadded:: 3.19
+
+Target file component generator expressions do not add target dependencies.
+
+The following target-based generator expressions that query for directory or
+file name components no longer add a dependency on the evaluated target.
+
+    - ``TARGET_FILE_DIR``
+    - ``TARGET_LINKER_FILE_BASE_NAME``
+    - ``TARGET_LINKER_FILE_NAME``
+    - ``TARGET_LINKER_FILE_DIR``
+    - ``TARGET_SONAME_FILE_NAME``
+    - ``TARGET_SONAME_FILE_DIR``
+    - ``TARGET_PDB_FILE_NAME``
+    - ``TARGET_PDB_FILE_DIR``
+    - ``TARGET_BUNDLE_DIR``
+    - ``TARGET_BUNDLE_CONTENT_DIR``
+
+
+In CMake 3.18 and lower a dependency on the evaluated target of the above
+generator expressions would be always added.  CMake 3.19 and above prefer
+to not add this dependency.  This policy provides compatibility for projects
+that have not been updated to expect the new behavior.
+
+The ``OLD`` behavior for this policy is to add a dependency on the evaluated
+target for the the above generator expressions.  The ``NEW`` behavior of
+this policy is to not add a dependency on the evaluated target for the the
+above generator expressions.
+
+This policy was introduced in CMake version 3.19.  Unlike many policies,
+CMake version |release| does *not* warn by default when this policy
+is not set and simply uses ``OLD`` behavior.  See documentation of the
+:variable:`CMAKE_POLICY_WARNING_CMP0112 <CMAKE_POLICY_WARNING_CMP<NNNN>>`
+variable to control the warning.
+
+.. include:: DEPRECATED.txt