Explicitly report config overrides and their paths

Author: ianfixes

Diff for: CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - C++ definitions of `ARDUINO_CI_COMPILATION_MOCKS` and `ARDUINO_CI_GODMODE` to aid in compilation macros
 - `CIConfig.available_override_config_path()` to search for available override files in standard locations
 - `CIConfig.override_file_from_project_library` and `CIConfig.override_file_from_example` to expose config locations
+- CI runner script now expliclty informs about config overrides
 
 ### Changed
 - `CIConfig` now uses `Pathname` instead of strings

Diff for: exe/arduino_ci.rb

@@ -493,7 +493,14 @@ def perform_example_compilation_tests(cpp_library, config)
     puts
     inform("Discovered example sketch") { example_name }
 
-    ovr_config = config.from_example(example_path)
+    example_config_file = config.override_file_from_example(example_path)
+    ovr_config = if example_config_file.nil?
+      config
+    else
+      inform("Using configuration override from example") { example_config_file }
+      config.from_example(example_path)
+    end
+
     platforms = choose_platform_set(ovr_config, "library example", ovr_config.platforms_to_build, cpp_library.library_properties)
 
     # having no platforms defined is probably an error
@@ -541,7 +548,15 @@ def perform_example_compilation_tests(cpp_library, config)
 inform("Working directory") { Dir.pwd }
 
 # initialize command and config
-config = ArduinoCI::CIConfig.default.from_project_library
+default_config = ArduinoCI::CIConfig.default
+library_config_file = default_config.override_file_from_project_library
+config = if library_config_file.nil?
+  default_config
+else
+  inform("Using configuration override from project") { library_config_file }
+  default_config.from_project_library
+end
+
 @backend = ArduinoCI::ArduinoInstallation.autolocate!
 inform("Located arduino-cli binary") { @backend.binary_path.to_s }
 if @backend.lib_dir.exist?