From 99f8a811fd335ef913fbc8e022293e423542f803 Mon Sep 17 00:00:00 2001
From: Angus Gratton <angus@espressif.com>
Date: Mon, 15 Apr 2019 11:15:58 +1000
Subject: [PATCH] cmake: Warn if something which looks like a component
 directory isn't

Otherwise, fails build at the add_subdirectory stage
---
 CMakeLists.txt              |  2 +-
 tools/cmake/component.cmake | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c98d3d8c5e..a65cb36fa0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -110,7 +110,7 @@ foreach(component_target ${build_component_targets})
     set(COMPONENT_NAME ${_name})
     set(COMPONENT_DIR ${dir})
     set(COMPONENT_ALIAS ${alias})
-    set(COMPONENT_PATH ${dir}) # same deprecation situation here
+    set(COMPONENT_PATH ${dir}) # also deprecated, see comment in previous loop
     idf_build_get_property(build_prefix __PREFIX)
     set(__idf_component_context 1)
     if(NOT prefix STREQUAL build_prefix)
diff --git a/tools/cmake/component.cmake b/tools/cmake/component.cmake
index ccb7bc02a1..2f65dca2ec 100644
--- a/tools/cmake/component.cmake
+++ b/tools/cmake/component.cmake
@@ -112,6 +112,18 @@ function(__component_add component_dir prefix)
     get_filename_component(abs_dir ${component_dir} ABSOLUTE)
     get_filename_component(base_dir ${abs_dir} NAME)
 
+    # Check this is really a directory and that a CMakeLists.txt file for this component exists
+    # - warn and skip anything which isn't valid looking (probably cruft)
+    if(NOT IS_DIRECTORY "${abs_dir}")
+        message(WARNING "Unexpected file in components directory: ${abs_dir}")
+        return()
+    endif()
+    if(NOT EXISTS "${abs_dir}/CMakeLists.txt")
+        message(WARNING "Component directory ${abs_dir} does not contain a CMakeLists.txt file. "
+            "No component will be added")
+        return()
+    endif()
+
     set(component_name ${base_dir})
     # The component target has three underscores as a prefix. The corresponding component library
     # only has two.