CMP0115: Require source file extensions to be explicit

3 files changed, 47 insertions, 0 deletions

diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst
index 0392325..0836883 100644
--- a/Help/manual/cmake-policies.7.rst
+++ b/Help/manual/cmake-policies.7.rst
@@ -51,6 +51,14 @@ The :variable:`CMAKE_MINIMUM_REQUIRED_VERSION` variable may also be used
 to determine whether to report an error on use of deprecated macros or
 functions.
 
+Policies Introduced by CMake 3.20
+=================================
+
+.. toctree::
+   :maxdepth: 1
+
+   CMP0115: Source file extensions must be explicit. </policy/CMP0115>
+
 Policies Introduced by CMake 3.19
 =================================
 
diff --git a/Help/policy/CMP0115.rst b/Help/policy/CMP0115.rst
new file mode 100644
index 0000000..7f82c43
--- /dev/null
+++ b/Help/policy/CMP0115.rst
@@ -0,0 +1,34 @@
+CMP0115
+-------
+
+.. versionadded:: 3.20
+
+Source file extensions must be explicit.
+
+In CMake 3.19 and below, if a source file could not be found by the name
+specified, it would append a list of known extensions to the name to see if
+the file with the extension could be found. For example, this would allow the
+user to run:
+
+.. code-block:: cmake
+
+  add_executable(exe main)
+
+and put ``main.c`` in the executable without specifying the extension.
+
+Starting in CMake 3.20, CMake prefers all source files to have their extensions
+explicitly listed:
+
+.. code-block:: cmake
+
+  add_executable(exe main.c)
+
+The ``OLD`` behavior for this policy is to implicitly append known extensions
+to source files if they can't be found. The ``NEW`` behavior of this policy is
+to not append known extensions and require them to be explicit.
+
+This policy was introduced in CMake version 3.20.  CMake version |release|
+warns when the policy is not set and uses ``OLD`` behavior. Use the
+:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly.
+
+.. include:: DEPRECATED.txt
diff --git a/Help/release/dev/explicit-source-extensions.rst b/Help/release/dev/explicit-source-extensions.rst
new file mode 100644
index 0000000..ccd9339
--- /dev/null
+++ b/Help/release/dev/explicit-source-extensions.rst
@@ -0,0 +1,5 @@
+explicit-source-extensions
+--------------------------
+
+* Source file extensions must now be explicit. See policy :policy:`CMP0115` for
+  details.