From baec453b9f5e63c83a04bb92e410aba0aae92ba4 Mon Sep 17 00:00:00 2001
From: mijoku <39005456+mijoku@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:33:09 +0100
Subject: [PATCH 1/3] Make public include directories SYSTEM-includes

With this change compile commands generated by cmake for targets consuming nanobind use `-isystem`  instead of `-I` for defining nanobind's header locations, which makes modern analysis tools (e.g. clang analyzer) ignore them.
---
 cmake/nanobind-config.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/nanobind-config.cmake b/cmake/nanobind-config.cmake
index 312e828f..9040cbcd 100644
--- a/cmake/nanobind-config.cmake
+++ b/cmake/nanobind-config.cmake
@@ -236,7 +236,7 @@ function (nanobind_build_library TARGET_NAME)
       ${NB_DIR}/ext/robin_map/include)
   endif()
 
-  target_include_directories(${TARGET_NAME} PUBLIC
+  target_include_directories(${TARGET_NAME} SYSTEM PUBLIC
     ${Python_INCLUDE_DIRS}
     ${NB_DIR}/include)
 

From 25b5a17177703896f8747c75ce509953c881b740 Mon Sep 17 00:00:00 2001
From: mijoku <39005456+mijoku@users.noreply.github.com>
Date: Mon, 27 Jan 2025 10:27:14 +0100
Subject: [PATCH 2/3] Header dirs as SYSTEM shall not be default but an opt-in

Using option `NB_SUPPRESS_WARNINGS` on function `add_nanobind_module` to
enable this behaviour.
---
 cmake/nanobind-config.cmake | 17 ++++++++++++++---
 docs/api_cmake.rst          |  3 +++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/cmake/nanobind-config.cmake b/cmake/nanobind-config.cmake
index 9040cbcd..e0871886 100644
--- a/cmake/nanobind-config.cmake
+++ b/cmake/nanobind-config.cmake
@@ -104,6 +104,9 @@ endfunction()
 # ---------------------------------------------------------------------------
 
 function (nanobind_build_library TARGET_NAME)
+  cmake_parse_arguments(PARSE_ARGV 1 ARG
+    "AS_SYSINCLUDE" "" "")
+
   if (TARGET ${TARGET_NAME})
     return()
   endif()
@@ -114,6 +117,10 @@ function (nanobind_build_library TARGET_NAME)
     set (TARGET_TYPE SHARED)
   endif()
 
+  if (${ARG_AS_SYSINCLUDE})
+    set (AS_SYSINCLUDE SYSTEM)
+  endif()
+
   add_library(${TARGET_NAME} ${TARGET_TYPE}
     EXCLUDE_FROM_ALL
     ${NB_DIR}/include/nanobind/make_iterator.h
@@ -236,7 +243,7 @@ function (nanobind_build_library TARGET_NAME)
       ${NB_DIR}/ext/robin_map/include)
   endif()
 
-  target_include_directories(${TARGET_NAME} SYSTEM PUBLIC
+  target_include_directories(${TARGET_NAME} ${AS_SYSINCLUDE} PUBLIC
     ${Python_INCLUDE_DIRS}
     ${NB_DIR}/include)
 
@@ -310,7 +317,7 @@ endfunction()
 
 function(nanobind_add_module name)
   cmake_parse_arguments(PARSE_ARGV 1 ARG
-    "STABLE_ABI;FREE_THREADED;NB_STATIC;NB_SHARED;PROTECT_STACK;LTO;NOMINSIZE;NOSTRIP;MUSL_DYNAMIC_LIBCPP"
+    "STABLE_ABI;FREE_THREADED;NB_STATIC;NB_SHARED;PROTECT_STACK;LTO;NOMINSIZE;NOSTRIP;MUSL_DYNAMIC_LIBCPP;NB_SUPPRESS_WARNINGS"
     "NB_DOMAIN" "")
 
   add_library(${name} MODULE ${ARG_UNPARSED_ARGUMENTS})
@@ -355,7 +362,11 @@ function(nanobind_add_module name)
     set(libname ${libname}-${ARG_NB_DOMAIN})
   endif()
 
-  nanobind_build_library(${libname})
+  if (ARG_NB_SUPPRESS_WARNINGS)
+    set(EXTRA_LIBRARY_PARAMS AS_SYSINCLUDE)
+  endif()
+
+  nanobind_build_library(${libname} ${EXTRA_LIBRARY_PARAMS})
 
   if (ARG_NB_DOMAIN)
     target_compile_definitions(${name} PRIVATE NB_DOMAIN=${ARG_NB_DOMAIN})
diff --git a/docs/api_cmake.rst b/docs/api_cmake.rst
index 17a15b67..d250c676 100644
--- a/docs/api_cmake.rst
+++ b/docs/api_cmake.rst
@@ -83,6 +83,9 @@ The high-level interface consists of just one CMake command:
         - The opposite of ``NB_STATIC``: compile the core nanobind library
           as a shared library for use in projects that consist of multiple
           extensions.
+      * - ``NB_SUPPRESS_WARNINGS``
+        - Mark nanobind's include directories as system includes, suppressing
+          warnings generated from nanobind's and Python's header files.
       * - ``PROTECT_STACK``
         - Don't remove stack smashing-related protections.
       * - ``LTO``

From a1e65d2d981256d0cd631d48f6a5c1e5746f8d07 Mon Sep 17 00:00:00 2001
From: mijoku <39005456+mijoku@users.noreply.github.com>
Date: Mon, 27 Jan 2025 13:18:11 +0100
Subject: [PATCH 3/3] change NB_SUPPRESS_WARNINGS documentation as suggested

---
 docs/api_cmake.rst | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/docs/api_cmake.rst b/docs/api_cmake.rst
index d250c676..eab178ae 100644
--- a/docs/api_cmake.rst
+++ b/docs/api_cmake.rst
@@ -84,8 +84,12 @@ The high-level interface consists of just one CMake command:
           as a shared library for use in projects that consist of multiple
           extensions.
       * - ``NB_SUPPRESS_WARNINGS``
-        - Mark nanobind's include directories as system includes, suppressing
-          warnings generated from nanobind's and Python's header files.
+        - Mark the include directories of nanobind and Python as
+          [SYSTEM](https://cmake.org/cmake/help/latest/command/include_directories.html)
+          include directories, which suppresses any potential warning messages
+          originating there. This is mainly of relevance if your project artificially
+          raises the warning level via flags like `-pedantic`, ``-Wcast-qual``,
+          ``-Wsign-conversion``.
       * - ``PROTECT_STACK``
         - Don't remove stack smashing-related protections.
       * - ``LTO``