docs: changed bootloader extra component to a property in build-system.rst

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

@@ -247,7 +247,7 @@ These variables all have default values that can be overridden for custom behavi
 
 - ``BOOTLOADER_IGNORE_EXTRA_COMPONENT``: Optional list of components, placed in ``bootloader_components/``, that should be ignored by the bootloader compilation. Use this variable if a bootloader component needs to be included conditionally inside the project.
 
-- ``BOOTLOADER_EXTRA_COMPONENT_DIRS``: Optional list of additional directories to search for components to be compiled as part of the bootloader.
+- ``BOOTLOADER_EXTRA_COMPONENT_DIRS``: Optional list of additional directories to search for components to be compiled as part of the bootloader. Please note that this is a build property.
 
 Any paths in these variables can be absolute paths, or set relative to the project directory.
 
@@ -783,11 +783,11 @@ It is important to note that this can also be used for any other bootloader comp
 
 See :example:`custom_bootloader/bootloader_override` for an example of overriding the default bootloader.
 
-Similarly to regular applications, it is possible to include external components, not placed in `bootloader_component`, as part of the bootloader build thanks to the CMake variable ``BOOTLOADER_EXTRA_COMPONENT_DIRS``. It can either refer to a directory that contains several components, either refer to a single component. For example:
+Similarly to regular applications, it is possible to include external components, not placed in `bootloader_component`, as part of the bootloader build thanks to the build property ``BOOTLOADER_EXTRA_COMPONENT_DIRS``. It can either refer to a directory that contains several components, or refer to a single component. For example:
 
     include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 
-    set(BOOTLOADER_EXTRA_COMPONENT_DIRS "/path/to/extra/component/")
+    idf_build_set_property(BOOTLOADER_EXTRA_COMPONENT_DIRS "/path/to/extra/component/" APPEND)
 
     project(main)
 

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

@@ -245,9 +245,9 @@ ESP-IDF 适用于 Python 3.8 以上版本。
 
 - ``COMPONENTS``：要构建进项目中的组件名称列表，默认为 ``COMPONENT_DIRS`` 目录下检索到的所有组件。使用此变量可以“精简”项目以缩短构建时间。请注意，如果一个组件通过 ``COMPONENT_REQUIRES`` 指定了它依赖的另一个组件，则会自动将其添加到 ``COMPONENTS`` 中，所以 ``COMPONENTS`` 列表可能会非常短。
 
-- ``BOOTLOADER_IGNORE_EXTRA_COMPONENT``：可选组件列表，位于 ``bootloader_components/`` 目录中，引导加载程序编译时会忽略该列表。使用这一变量可以将一个组件有条件地包含在项目中。
+- ``BOOTLOADER_IGNORE_EXTRA_COMPONENT``：可选组件列表，位于 ``bootloader_components/`` 目录中，引导加载程序编译时会忽略该列表中的组件。使用这一变量可以将一个组件有条件地包含在项目中。
 
-- ``BOOTLOADER_EXTRA_COMPONENT_DIRS``：可选的附加路径列表，引导加载程序编译时将从这些路径中搜索要编译的组件。
+- ``BOOTLOADER_EXTRA_COMPONENT_DIRS``：可选的附加路径列表，引导加载程序编译时将从这些路径中搜索要编译的组件。注意，这是一个构建属性。
 
 以上变量中的路径可以是绝对路径，或者是相对于项目目录的相对路径。
 
@@ -783,15 +783,15 @@ KConfig.projbuild
 
 请参考 :example:`custom_bootloader/bootloader_override` 查看覆盖默认引导加载程序的示例。
 
-与常规应用程序类似，通过 CMake 变量 ``BOOTLOADER_EXTRA_COMPONENT_DIRS`` 可以将不在 `bootloader_component` 中的外部组件作为引导加载程序的一部分进行构建。可以只引用一个组件，也可以引用包含多个组件的路径。例如：
+与常规应用程序类似，通过构建属性 ``BOOTLOADER_EXTRA_COMPONENT_DIRS`` 可以将不在 `bootloader_component` 中的外部组件作为引导加载程序的一部分进行构建。可以只引用一个组件，也可以引用包含多个组件的路径。例如：
 
     include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 
-    set(BOOTLOADER_EXTRA_COMPONENT_DIRS "/path/to/extra/component/")
+    idf_build_set_property(BOOTLOADER_EXTRA_COMPONENT_DIRS "/path/to/extra/component/" APPEND)
 
     project(main)
 
-请参考 :example:`custom_bootloader/bootloader_extra_dir` 查看向引导加载程序构建过程添加额外组件的示例。
+请参考示例 :example:`custom_bootloader/bootloader_extra_dir`，查看如何向引导加载程序构建过程添加额外的组件。
 
 .. _config_only_component:
 

examples/custom_bootloader/bootloader_extra_dir/README.md

@@ -7,7 +7,7 @@
 
 The purpose of this example is to show how to add a custom directory that contains a component to the bootloader build.
 
-Registering extra components for the bootloader can be done thanks to the CMake variable `BOOTLOADER_EXTRA_COMPONENT_DIRS`. It works the same way as the application's `EXTRA_COMPONENT_DIRS`, it can either refer to a directory that contains several components, either refer to a single component.
+Registering extra components for the bootloader can be done thanks to the IDF property `BOOTLOADER_EXTRA_COMPONENT_DIRS`. It can either refer to a directory that contains several components, either refer to a single component.
 
 ## Usage of this example:
 
@@ -33,14 +33,14 @@ User application is loaded and running.
 
 ## Organization of this example
 
-This project contains an application, in the `main` directory that represents an application. It also contains a `bootloader_components` that contains a component compiled and linked with the bootloader. This `bootloader_components` can contain several components, each of them would be in a different directory.
+This project contains a `main` directory that represents an application. It also has a `bootloader_components` directory that contains a component that will be compiled and linked with the bootloader. This `bootloader_components` can contain several components, each of them would be in a different directory.
 
-The directory `extra_bootloader_components/extra_component/` contains a component that is meant to be included in the bootloader build. To do so, the variable `BOOTLOADER_EXTRA_COMPONENT_DIRS` is set from the `CMakeLists.txt` file.
+The directory `extra_bootloader_components/extra_component/` contains a component that is meant to be included in the bootloader build. To do so, the CMake property `BOOTLOADER_EXTRA_COMPONENT_DIRS` is set from the `CMakeLists.txt` file.
 
 Below is a short explanation of files in the project folder.
 
 ```
-├── CMakeLists.txt             Defines the `BOOTLOADER_EXTRA_COMPONENT_DIRS` variable
+├── CMakeLists.txt             Defines the `BOOTLOADER_EXTRA_COMPONENT_DIRS` property
 ├── main
 │   ├── CMakeLists.txt
 │   └── main.c                 User application