From 9e350c177403ead4c8a6630a08f36f304b04484c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Thu, 21 Aug 2025 23:51:38 +0200
Subject: [PATCH] Add and use __attribute__((nonnull)) in dnssec-signzone.c

Clang 20 is complaining about passing NULL to an argument with 'nonnull'
attribute.  Mark these two functions with the same attribute to assure
that these two function also don't accept NULL as an argument.
---
 bin/dnssec/dnssec-signzone.c     | 5 +++++
 lib/isc/include/isc/attributes.h | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/bin/dnssec/dnssec-signzone.c b/bin/dnssec/dnssec-signzone.c
index 6eb72eebaf..025f5703ff 100644
--- a/bin/dnssec/dnssec-signzone.c
+++ b/bin/dnssec/dnssec-signzone.c
@@ -3085,6 +3085,8 @@ writeset(const char *prefix, dns_rdatatype_t type) {
 	dns_db_detach(&db);
 }
 
+static void
+print_time(FILE *fp) ISC_ATTR_NONNULL(1);
 static void
 print_time(FILE *fp) {
 	time_t currenttime = time(NULL);
@@ -3101,6 +3103,8 @@ print_time(FILE *fp) {
 	fprintf(fp, "; File written on %s\n", timebuf);
 }
 
+static void
+print_version(FILE *fp) ISC_ATTR_NONNULL(1);
 static void
 print_version(FILE *fp) {
 	if (outputformat != dns_masterformat_text) {
@@ -3908,6 +3912,7 @@ main(int argc, char *argv[]) {
 			fatal("failed to open temporary output file: %s",
 			      isc_result_totext(result));
 		}
+		INSIST(outfp != NULL);
 		removefile = true;
 		setfatalcallback(&removetempfile);
 	}
diff --git a/lib/isc/include/isc/attributes.h b/lib/isc/include/isc/attributes.h
index 96d57f9f49..03c84ae497 100644
--- a/lib/isc/include/isc/attributes.h
+++ b/lib/isc/include/isc/attributes.h
@@ -112,3 +112,9 @@
 #else
 #define ISC_ATTR_COUNTED_BY(x)
 #endif
+
+#if __has_attribute(__nonnull__)
+#define ISC_ATTR_NONNULL(...) __attribute__((__nonnull__(__VA_ARGS__)))
+#else
+#define ISC_ATTR_NONNULL(...)
+#endif