diff --git a/CMakeLists.txt b/CMakeLists.txt
index 362c68984..2c6ef7621 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,7 +32,13 @@ execute_process(COMMAND "${CMAKE_COMMAND}"
     -D "IDF_PATH=${IDF_PATH}"
     -D "DEBUG=${DEBUG}"
     -P "${IDF_PATH}/tools/cmake/scripts/expand_requirements.cmake"
-    WORKING_DIRECTORY "${PROJECT_PATH}")
+    WORKING_DIRECTORY "${PROJECT_PATH}"
+    RESULT_VARIABLE expand_requirements_result)
+
+if(expand_requirements_result)
+    message(FATAL_ERROR "Failed to expand component requirements")
+endif()
+
 include("${CMAKE_BINARY_DIR}/component_depends.cmake")
 
 #
diff --git a/docs/en/api-guides/build-system-cmake.rst b/docs/en/api-guides/build-system-cmake.rst
index ac27d8e3d..31130a860 100644
--- a/docs/en/api-guides/build-system-cmake.rst
+++ b/docs/en/api-guides/build-system-cmake.rst
@@ -342,12 +342,14 @@ The following variables are set at the project level, but available for use in c
 - ``CONFIG_*``: Each value in the project configuration has a corresponding variable available in make. All names begin with ``CONFIG_``. :doc:`More information here </api-reference/kconfig>`.
 - ``IDF_VER``: Git version of ESP-IDF (produced by ``git describe``)
 - ``IDF_TARGET``: Name of the target for which the project is being built.
-- ``PROJECT_VER``: Project version. 
+- ``PROJECT_VER``: Project version.
 
-* If ``PROJECT_VER`` variable set in project CMakeLists.txt file, its value will be used.
-* Else, if the ``$PROJECT_PATH/version.txt`` exists, its contents will be used as ``PROJECT_VER``.
-* Else, if the project is located inside a Git repository, the output of git describe will be used.
-* Otherwise, ``PROJECT_VER`` will be "1".
+  * If ``PROJECT_VER`` variable set in project CMakeLists.txt file, its value will be used.
+  * Else, if the ``$PROJECT_PATH/version.txt`` exists, its contents will be used as ``PROJECT_VER``.
+  * Else, if the project is located inside a Git repository, the output of git describe will be used.
+  * Otherwise, ``PROJECT_VER`` will be "1".
+
+- ``ESP_PLATFORM``: Set to 1 whenever the ESP-IDF build system is being used.
 
 If you modify any of these variables inside ``CMakeLists.txt`` then this will not prevent other components from building but it may make your component hard to build and/or debug.
 
@@ -903,6 +905,9 @@ import it from other projects. Studying the library's CMakeLists.txt and build s
 It is also possible to wrap a third-party library to be used as a component in this manner. For example, the :component:`mbedtls` component is a wrapper for 
 Espressif's fork of `mbedtls <https://github.com/ARMmbed/mbedtls>`_. See its :component_file:`component CMakeLists.txt <mbedtls/CMakeLists.txt>`.
 
+The CMake variable ``ESP_PLATFORM`` is set to 1 whenever the ESP-IDF build system is being used. Tests such as ``if (ESP_PLATFORM)`` can be used in generic CMake code if special IDF-specific logic is required.
+
+
 Using ESP-IDF in Custom CMake Projects
 ======================================
 
diff --git a/tools/cmake/idf_functions.cmake b/tools/cmake/idf_functions.cmake
index 7b389d342..3ea818ec8 100644
--- a/tools/cmake/idf_functions.cmake
+++ b/tools/cmake/idf_functions.cmake
@@ -62,6 +62,8 @@ macro(idf_set_variables)
 
     set(IDF_PROJECT_PATH "${CMAKE_SOURCE_DIR}")
 
+    set(ESP_PLATFORM 1 CACHE BOOL INTERNAL)
+
     spaces2list(IDF_COMPONENT_DIRS)
     spaces2list(IDF_COMPONENTS)
     spaces2list(IDF_COMPONENT_REQUIRES_COMMON)
diff --git a/tools/cmake/scripts/expand_requirements.cmake b/tools/cmake/scripts/expand_requirements.cmake
index bcfa76aa4..5886e6320 100644
--- a/tools/cmake/scripts/expand_requirements.cmake
+++ b/tools/cmake/scripts/expand_requirements.cmake
@@ -33,6 +33,8 @@ cmake_minimum_required(VERSION 3.5)
 include("${IDF_PATH}/tools/cmake/utilities.cmake")
 include("${IDF_PATH}/tools/cmake/component_utils.cmake")
 
+set(ESP_PLATFORM 1)
+
 if(NOT DEPENDENCIES_FILE)
     message(FATAL_ERROR "DEPENDENCIES_FILE must be set.")
 endif()
diff --git a/tools/idf.py b/tools/idf.py
index 16086b4ec..5550fc430 100755
--- a/tools/idf.py
+++ b/tools/idf.py
@@ -165,7 +165,7 @@ def _ensure_build_directory(args, always_run_cmake=False):
         if args.generator is None:
             args.generator = detect_cmake_generator()
         try:
-            cmake_args = ["cmake", "-G", args.generator, "-DPYTHON_DEPS_CHECKED=1"]
+            cmake_args = ["cmake", "-G", args.generator, "-DPYTHON_DEPS_CHECKED=1", "-DESP_PLATFORM=1"]
             if not args.no_warnings:
                 cmake_args += ["--warn-uninitialized"]
             if args.no_ccache: