cmake: allow multiple sdkconfig defaults to be specified

docs/en/api-guides/build-system.rst

@@ -904,14 +904,14 @@ Custom sdkconfig defaults
 
 For example projects or other projects where you don't want to specify a full sdkconfig configuration, but you do want to override some key values from the ESP-IDF defaults, it is possible to create a file ``sdkconfig.defaults`` in the project directory. This file will be used when creating a new config from scratch, or when any new config value hasn't yet been set in the ``sdkconfig`` file.
 
-To override the name of this file, set the ``SDKCONFIG_DEFAULTS`` environment variable.
+To override the name of this file or to specify multiple files, set the ``SDKCONFIG_DEFAULTS`` environment variable or set ``SDKCONFIG_DEFAULTS`` in top-level CMakeLists.txt. If specifying multiple files, use semicolon as the list separator. File names not specified as full paths are resolved relative to current project.
 
 Target-dependent sdkconfig defaults
 -----------------------------------
 
 In addition to ``sdkconfig.defaults`` file, build system will also load defaults from ``sdkconfig.defaults.TARGET_NAME`` file, where ``TARGET_NAME`` is the value of ``IDF_TARGET``. For example, for ``esp32`` target, default settings will be taken from ``sdkconfig.defaults`` first, and then from ``sdkconfig.defaults.esp32``.
 
-If ``SDKCONFIG_DEFAULTS`` is used to override the name of defaults file, the name of target-specific defaults file will be derived from ``SDKCONFIG_DEFAULTS`` value.
+If ``SDKCONFIG_DEFAULTS`` is used to override the name of defaults file/files, the name of target-specific defaults file will be derived from ``SDKCONFIG_DEFAULTS`` value/values using the rule above.
 
 
 Flash arguments
@@ -1099,7 +1099,7 @@ The call requires the target chip to be specified with *target* argument. Option
 - PROJECT_NAME - name of the project; defaults to CMAKE_PROJECT_NAME
 - PROJECT_VER - version/revision of the project; defaults to "1"
 - SDKCONFIG - output path of generated sdkconfig file; defaults to PROJECT_DIR/sdkconfig or CMAKE_SOURCE_DIR/sdkconfig depending if PROJECT_DIR is set
-- SDKCONFIG_DEFAULTS - defaults file to use for the build; defaults to empty
+- SDKCONFIG_DEFAULTS - list of files containing default config to use in the build (list must contain full paths); defaults to empty. For each value *filename* in the list, the config from file *filename.target*, if it exists, is also loaded.
 - BUILD_DIR - directory to place ESP-IDF build-related artifacts, such as generated binaries, text files, components; defaults to CMAKE_BINARY_DIR
 - COMPONENTS - select components to process among the components known by the build system (added via `idf_build_component`). This argument is used to trim the build. 
   Other components are automatically added if they are required in the dependency chain, i.e. 
@@ -1154,7 +1154,7 @@ For example, to get the Python interpreter used for the build:
   - PROJECT_VER - version of the project; set from ``idf_build_process`` PROJECT_VER argument
   - PYTHON - Python interpreter used for the build; set from PYTHON environment variable if available, if not "python" is used
   - SDKCONFIG - full path to output config file; set from ``idf_build_process`` SDKCONFIG argument
-  - SDKCONFIG_DEFAULTS - full path to config defaults file; set from ``idf_build_process`` SDKCONFIG_DEFAULTS argument
+  - SDKCONFIG_DEFAULTS - list of files containing default config to use in the build; set from ``idf_build_process`` SDKCONFIG_DEFAULTS argument
   - SDKCONFIG_HEADER - full path to C/C++ header file containing component configuration; set by ``idf_build_process``
   - SDKCONFIG_CMAKE - full path to CMake file containing component configuration; set by ``idf_build_process``
   - SDKCONFIG_JSON - full path to JSON file containing component configuration; set by ``idf_build_process``

tools/cmake/build.cmake

@@ -367,8 +367,8 @@ endfunction()
 #                       are processed.
 macro(idf_build_process target)
     set(options)
-    set(single_value PROJECT_DIR PROJECT_VER PROJECT_NAME BUILD_DIR SDKCONFIG SDKCONFIG_DEFAULTS)
-    set(multi_value COMPONENTS)
+    set(single_value PROJECT_DIR PROJECT_VER PROJECT_NAME BUILD_DIR SDKCONFIG)
+    set(multi_value COMPONENTS SDKCONFIG_DEFAULTS)
     cmake_parse_arguments(_ "${options}" "${single_value}" "${multi_value}" ${ARGN})
 
     idf_build_set_property(BOOTLOADER_BUILD "${BOOTLOADER_BUILD}")

tools/cmake/kconfig.cmake

@@ -158,11 +158,17 @@ function(__kconfig_generate_config sdkconfig sdkconfig_defaults)
     idf_build_set_property(CONFIG_ENV_PATH ${config_env_path})
 
     if(sdkconfig_defaults)
-        set(defaults_arg --defaults "${sdkconfig_defaults}")
+        foreach(sdkconfig_default ${sdkconfig_defaults})
+            list(APPEND defaults_arg --defaults "${sdkconfig_default}")
+        endforeach()
     endif()
 
-    if(EXISTS "${sdkconfig_defaults}.${idf_target}")
-        list(APPEND defaults_arg --defaults "${sdkconfig_defaults}.${idf_target}")
+    if(sdkconfig_defaults)
+        foreach(sdkconfig_default ${sdkconfig_defaults})
+            if(EXISTS "${sdkconfig_default}.${idf_target}")
+                list(APPEND defaults_arg --defaults "${sdkconfig_default}.${idf_target}")
+            endif()
+        endforeach()
     endif()
 
     idf_build_get_property(root_kconfig __ROOT_KCONFIG)

tools/cmake/project.cmake

@@ -314,10 +314,13 @@ macro(project project_name)
     # PROJECT_DIR is set to the current directory
     # PROJECT_VER is from the version text or git revision of the current repo
     if(SDKCONFIG_DEFAULTS)
-        get_filename_component(sdkconfig_defaults "${SDKCONFIG_DEFAULTS}" ABSOLUTE)
-        if(NOT EXISTS "${sdkconfig_defaults}")
-            message(FATAL_ERROR "SDKCONFIG_DEFAULTS '${sdkconfig_defaults}' does not exist.")
-        endif()
+        foreach(sdkconfig_default ${SDKCONFIG_DEFAULTS})
+            get_filename_component(sdkconfig_default "${sdkconfig_default}" ABSOLUTE)
+            if(NOT EXISTS "${sdkconfig_default}")
+                message(FATAL_ERROR "SDKCONFIG_DEFAULTS '${sdkconfig_default}' does not exist.")
+            endif()
+            list(APPEND sdkconfig_defaults ${sdkconfig_default})
+        endforeach()
     else()
         if(EXISTS "${CMAKE_SOURCE_DIR}/sdkconfig.defaults")
             set(sdkconfig_defaults "${CMAKE_SOURCE_DIR}/sdkconfig.defaults")

tools/unit-test-app/idf_ext.py

@@ -71,29 +71,18 @@ def action_extensions(base_actions, project_path=os.getcwd()):
 
             # Clean up and set idf-target
             base_actions["actions"]["fullclean"]["callback"]("fullclean", ctx, args)
-            base_actions["actions"]["set-target"]["callback"]("set-target", ctx, args, target)
 
             new_cache_values["EXCLUDE_COMPONENTS"] = config.get("EXCLUDE_COMPONENTS", "''")
             new_cache_values["TEST_EXCLUDE_COMPONENTS"] = config.get("TEST_EXCLUDE_COMPONENTS", "''")
             new_cache_values["TEST_COMPONENTS"] = config.get("TEST_COMPONENTS", "''")
             new_cache_values["TESTS_ALL"] = int(new_cache_values["TEST_COMPONENTS"] == "''")
-
-            # write a new sdkconfig file from the combined defaults and the config
-            # value folder
-            with open(os.path.join(project_path, "sdkconfig"), "w") as sdkconfig:
-                sdkconfig_default = os.path.join(project_path, "sdkconfig.defaults")
-
-                with open(sdkconfig_default, "rb") as sdkconfig_default_file:
-                    sdkconfig.write(sdkconfig_default_file.read())
-
-                sdkconfig_config = os.path.join(project_path, "configs", config_name)
-                with open(sdkconfig_config, "rb") as sdkconfig_config_file:
-                    sdkconfig.write(b"\n")
-                    sdkconfig.write(sdkconfig_config_file.read())
+            new_cache_values["IDF_TARGET"] = target
+            new_cache_values["SDKCONFIG_DEFAULTS"] = ";".join([os.path.join(project_path, "sdkconfig.defaults"), config_path])
 
             args.define_cache_entry.extend(["%s=%s" % (k, v) for k, v in new_cache_values.items()])
 
-            base_actions["actions"]["reconfigure"]["callback"](None, ctx, args)
+            reconfigure = base_actions["actions"]["reconfigure"]["callback"]
+            reconfigure(None, ctx, args)
 
     # This target builds the configuration. It does not currently track dependencies,
     # but is good enough for CI builds if used together with clean-all-configs.