From e16b366d03ab803da51c06885e5642190e974052 Mon Sep 17 00:00:00 2001
From: Allen Winter <winter@kde.org>
Date: Sun, 5 May 2024 19:18:37 -0400
Subject: [PATCH] Add __attribute__((sentinel)) to all _vanew function
 declarations

fixes: #604
---
 scripts/mkderivedproperties.pl       |  2 +-
 src/libical/CMakeLists.txt           |  1 +
 src/libical/icalcomponent.h          |  3 ++-
 src/libical/icalderivedproperty.h.in |  1 +
 src/libical/libical_sentinel.h       | 23 +++++++++++++++++++++++
 5 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 src/libical/libical_sentinel.h

diff --git a/scripts/mkderivedproperties.pl b/scripts/mkderivedproperties.pl
index 7e1d9065b..c936fe28a 100644
--- a/scripts/mkderivedproperties.pl
+++ b/scripts/mkderivedproperties.pl
@@ -302,7 +302,7 @@ sub insert_code
 LIBICAL_ICAL_EXPORT $type icalproperty_get_${lc}(const icalproperty *prop);";
 
       if ($include_vanew) {
-        print "\nLIBICAL_ICAL_EXPORT icalproperty *icalproperty_vanew_${lc}($type v, ...);\n";
+        print "\nLIBICAL_ICAL_EXPORT LIBICAL_SENTINEL icalproperty *icalproperty_vanew_${lc}($type v, ...);\n";
       }
 
     }
diff --git a/src/libical/CMakeLists.txt b/src/libical/CMakeLists.txt
index 370e26d32..aeff8b377 100644
--- a/src/libical/CMakeLists.txt
+++ b/src/libical/CMakeLists.txt
@@ -432,6 +432,7 @@ install(FILES
   icaltypes.h
   icalvalue.h
   libical_deprecated.h
+  libical_sentinel.h
   libical_ical_export.h
   pvl.h
   sspm.h
diff --git a/src/libical/icalcomponent.h b/src/libical/icalcomponent.h
index ac0828f02..1e04efc40 100644
--- a/src/libical/icalcomponent.h
+++ b/src/libical/icalcomponent.h
@@ -16,6 +16,7 @@
 #define ICALCOMPONENT_H
 
 #include "libical_deprecated.h"
+#include "libical_sentinel.h"
 #include "libical_ical_export.h"
 #include "icalenums.h"  /* Defines icalcomponent_kind */
 #include "icalproperty.h"
@@ -51,7 +52,7 @@ LIBICAL_ICAL_EXPORT icalcomponent *icalcomponent_new_from_string(const char *str
  *
  * Make sure to pass NULL (not 0) as the final argument!
  */
-LIBICAL_ICAL_EXPORT icalcomponent *icalcomponent_vanew(icalcomponent_kind kind, ...);
+LIBICAL_ICAL_EXPORT LIBICAL_SENTINEL icalcomponent *icalcomponent_vanew(icalcomponent_kind kind, ...);
 
 /** @brief Constructor
  */
diff --git a/src/libical/icalderivedproperty.h.in b/src/libical/icalderivedproperty.h.in
index c5244dd84..e52492668 100644
--- a/src/libical/icalderivedproperty.h.in
+++ b/src/libical/icalderivedproperty.h.in
@@ -11,6 +11,7 @@
 #ifndef ICALDERIVEDPROPERTY_H
 #define ICALDERIVEDPROPERTY_H
 
+#include "libical_sentinel.h"
 #include "icalparameter.h"
 #include "icalderivedvalue.h"
 #include "icalrecur.h"
diff --git a/src/libical/libical_sentinel.h b/src/libical/libical_sentinel.h
new file mode 100644
index 000000000..7dd596d35
--- /dev/null
+++ b/src/libical/libical_sentinel.h
@@ -0,0 +1,23 @@
+/**
+  SPDX-FileCopyrightText: Allen Winter <winter@kde.org>
+  SPDX-License-Identifier: LGPL-2.1-only OR MPL-2.0
+*/
+
+#ifndef LIBICAL_SENTINEL_H
+#define LIBICAL_SENTINEL_H
+
+/* sentinel attribute macro */
+#if defined(NO_SENTINEL_WARNINGS)
+#define LIBICAL_SENTINEL
+#else
+#if !defined(LIBICAL_SENTINEL)
+#if defined(__GNUC__) || defined(__clang__)
+#define LIBICAL_SENTINEL __attribute__((sentinel))
+#else
+/* sentinel attributes are unknown to MSVC */
+#define LIBICAL_SENTINEL
+#endif
+#endif
+#endif
+
+#endif