Merge #13301: lint: Add linter to error on #include <*.cpp>

9d6c9dbb88 lint: Add linter to error on #include <*.cpp> (Ben Woosley)

Pull request description:

  Files should depend on one another by interface, not by implementation.
  This checks for quoted includes as well.

Tree-SHA512: d36d468f48d538077f5f927b9561729fd7d76319f6b2e2cc10414a9f243588194e90ca1d85eca65019f9259268f555d25106eaaa56da28c58fa8d5837b469661

test/lint/lint-includes.sh

@@ -33,6 +33,14 @@ for CPP_FILE in $(filter_suffix cpp); do
     fi
 done
 
+INCLUDED_CPP_FILES=$(git grep -E "^#include [<\"][^>\"]+\.cpp[>\"]" -- "*.cpp" "*.h")
+if [[ ${INCLUDED_CPP_FILES} != "" ]]; then
+    echo "The following files #include .cpp files:"
+    echo "${INCLUDED_CPP_FILES}"
+    echo
+    EXIT_CODE=1
+fi
+
 EXPECTED_BOOST_INCLUDES=(
     boost/algorithm/string.hpp
     boost/algorithm/string/case_conv.hpp