build: expand ${ZEPHYR_<module>_MODULE_DIR} in CONF_FILE, OVERLAY_CONFIG

cmake/app/boilerplate.cmake

@@ -444,7 +444,8 @@ if(DEFINED CONF_FILE)
 
   # In order to support a `prj_<name>.conf pattern for auto inclusion of board
   # overlays, then we must first ensure only a single conf file is provided.
-  string(REPLACE " " ";" CONF_FILE_AS_LIST "${CONF_FILE}")
+  string(CONFIGURE "${CONF_FILE}" CONF_FILE_EXPANDED)
+  string(REPLACE " " ";" CONF_FILE_AS_LIST "${CONF_FILE_EXPANDED}")
   list(LENGTH CONF_FILE_AS_LIST CONF_FILE_LENGTH)
   if(${CONF_FILE_LENGTH} EQUAL 1)
     # Need the file name to look for match.

cmake/dts.cmake

@@ -69,7 +69,8 @@ set(dts_files
 if(SUPPORTS_DTS)
   if(DTC_OVERLAY_FILE)
     # Convert from space-separated files into file list
-    string(REPLACE " " ";" DTC_OVERLAY_FILE_RAW_LIST "${DTC_OVERLAY_FILE}")
+    string(CONFIGURE "${DTC_OVERLAY_FILE}" DTC_OVERLAY_FILE_EXPANDED)
+    string(REPLACE " " ";" DTC_OVERLAY_FILE_RAW_LIST "${DTC_OVERLAY_FILE_EXPANDED}")
     foreach(file ${DTC_OVERLAY_FILE_RAW_LIST})
       file(TO_CMAKE_PATH "${file}" cmake_path_file)
       list(APPEND DTC_OVERLAY_FILE_AS_LIST ${cmake_path_file})

cmake/kconfig.cmake

@@ -52,11 +52,13 @@ set(DOTCONFIG                  ${PROJECT_BINARY_DIR}/.config)
 set(PARSED_KCONFIG_SOURCES_TXT ${PROJECT_BINARY_DIR}/kconfig/sources.txt)
 
 if(CONF_FILE)
-string(REPLACE " " ";" CONF_FILE_AS_LIST "${CONF_FILE}")
+  string(CONFIGURE "${CONF_FILE}" CONF_FILE_EXPANDED)
+  string(REPLACE " " ";" CONF_FILE_AS_LIST "${CONF_FILE_EXPANDED}")
 endif()
 
 if(OVERLAY_CONFIG)
-  string(REPLACE " " ";" OVERLAY_CONFIG_AS_LIST "${OVERLAY_CONFIG}")
+  string(CONFIGURE "${OVERLAY_CONFIG}" OVERLAY_CONFIG_EXPANDED)
+  string(REPLACE " " ";" OVERLAY_CONFIG_AS_LIST "${OVERLAY_CONFIG_EXPANDED}")
 endif()
 
 if((DEFINED BOARD_REVISION) AND EXISTS ${BOARD_DIR}/${BOARD}_${BOARD_REVISION_STRING}.conf)

doc/application/index.rst

@@ -478,7 +478,10 @@ Application Configuration Directory
 Zephyr will use configuration files from the application's configuration
 directory except for files with an absolute path provided by the arguments
 described earlier, for example ``CONF_FILE``, ``OVERLAY_CONFIG``, and
-``DTC_OVERLAY_FILE``.
+``DTC_OVERLAY_FILE``. A file in a Zephyr module can be referred by
+escaping the Zephyr module dir variable like this
+``\${ZEPHYR_<module>_MODULE_DIR}/<path-to>/<file>``
+when setting any of said variables.
 
 The application configuration directory is defined by the
 ``APPLICATION_CONFIG_DIR`` variable.

doc/guides/dts/howtos.rst

@@ -202,7 +202,10 @@ Set devicetree overlays
 Devicetree overlays are explained in :ref:`devicetree-intro`. The CMake
 variable :makevar:`DTC_OVERLAY_FILE` contains a space- or semicolon-separated
 list of overlay files to use. If :makevar:`DTC_OVERLAY_FILE` specifies multiple
-files, they are included in that order by the C preprocessor.
+files, they are included in that order by the C preprocessor. A file in a
+Zephyr module can be referred to by escaping the Zephyr module dir variable
+like `\${ZEPHYR_<module>_MODULE_DIR}/<path-to>/dts.overlay`
+when setting the DTC_OVERLAY_FILE variable.
 
 You can set :makevar:`DTC_OVERLAY_FILE` to contain exactly the files you want
 to use. Here is an :ref:`example <west-building-dtc-overlay-file>` using

tests/cmake/overlays/var_expansions/CMakeLists.txt

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+set(ZEPHYR_MODULES "${CMAKE_CURRENT_SOURCE_DIR}/my_module")
+set(ZEPHYR_EXTRA_MODULES "${CMAKE_CURRENT_SOURCE_DIR}/my_extra_module")
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(overlay_var_expansions)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

tests/cmake/overlays/var_expansions/my_extra_module/zephyr/module.yml

@@ -0,0 +1 @@
+name:  my_extra_module_name

tests/cmake/overlays/var_expansions/my_extra_module/zephyr/my_extra_module-board.overlay

@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2022 Legrand, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+        /* This file is intentionally empty */
+};

tests/cmake/overlays/var_expansions/my_extra_module/zephyr/my_extra_module-overlay.conf

@@ -0,0 +1 @@
+# extra-overlay-empty.conf

tests/cmake/overlays/var_expansions/my_module/zephyr/module.yml

@@ -0,0 +1 @@
+name:  my_module_name

tests/cmake/overlays/var_expansions/my_module/zephyr/my_module-board.overlay

@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2022 Legrand, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+        /* This file is intentionally empty */
+};

tests/cmake/overlays/var_expansions/my_module/zephyr/my_module-overlay.conf

@@ -0,0 +1 @@
+# overlay-empty.conf

tests/cmake/overlays/var_expansions/prj.conf

@@ -0,0 +1 @@
+CONFIG_ZTEST=y

tests/cmake/overlays/var_expansions/src/main.c

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2022 Legrand North America, LLC.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+#include <zephyr.h>
+#include <ztest.h>
+
+
+static void test_stub_for_build_only_test(void)
+{
+	ztest_test_pass();
+}
+
+void test_main(void)
+{
+	ztest_test_suite(cmake_overlay_var_expansions_test_suite,
+			 ztest_unit_test(test_stub_for_build_only_test));
+	ztest_run_test_suite(cmake_overlay_var_expansions_test_suite);
+}

tests/cmake/overlays/var_expansions/testcase.yaml

@@ -0,0 +1,11 @@
+common:
+  tags: cmake
+  build_only: true
+  platform_allow: native_posix
+tests:
+  cmake.overlays.var_expansions.CONF_FILE:
+    extra_args: CONF_FILE=${ZEPHYR_MY_MODULE_NAME_MODULE_DIR}/zephyr/my_module-overlay.conf;${ZEPHYR_MY_EXTRA_MODULE_NAME_MODULE_DIR}/zephyr/my_extra_module-overlay.conf;prj.conf
+  cmake.overlays.var_expansions.OVERLAY_CONFIG:
+    extra_args: OVERLAY_CONFIG=${ZEPHYR_MY_MODULE_NAME_MODULE_DIR}/zephyr/my_module-overlay.conf;${ZEPHYR_MY_EXTRA_MODULE_NAME_MODULE_DIR}/zephyr/my_extra_module-overlay.conf
+  cmake.overlays.var_expansions.DTC_OVERLAY_FILE:
+    extra_args: DTC_OVERLAY_FILE=${ZEPHYR_MY_MODULE_NAME_MODULE_DIR}/zephyr/my_module-board.overlay;${ZEPHYR_MY_EXTRA_MODULE_NAME_MODULE_DIR}/zephyr/my_extra_module-board.overlay