From d686636bf043a6f02e592658cad7ef6a091003d2 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 30 Aug 2017 14:05:16 +0200
Subject: [PATCH] core: avoid compiler warning in
 nm_ip_config_iter_ip4_address_for_each() macro
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  In file included from src/nm-ip6-config.c:24:0:
  src/nm-ip6-config.c: In function ‘nm_ip6_config_create_setting’:
  src/nm-ip6-config.c:734:62: error: the address of ‘address’ will always evaluate as ‘true’ [-Werror=address]
    nm_ip_config_iter_ip6_address_for_each (&ipconf_iter, self, &address) {
                                                                ^
  src/nm-ip6-config.h:60:17: note: in definition of macro ‘nm_ip_config_iter_ip6_address_for_each’
       for (({ if (address) { *(((const NMPlatformIP6Address **) address)) = NULL; } }), nm_ip_config_iter_ip6_address_init ((iter), (self)); \
                   ^

Fixes: 6e9aa9402a67bab563320fb0b37df242df15214c
---
 shared/nm-utils/nm-macros-internal.h | 15 +++++++++++++++
 src/nm-ip4-config.h                  |  4 ++--
 src/nm-ip6-config.h                  |  4 ++--
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/shared/nm-utils/nm-macros-internal.h b/shared/nm-utils/nm-macros-internal.h
index 66b4aa8d60..613e0432e1 100644
--- a/shared/nm-utils/nm-macros-internal.h
+++ b/shared/nm-utils/nm-macros-internal.h
@@ -687,6 +687,21 @@ nm_clear_g_cancellable (GCancellable **cancellable)
 
 /*****************************************************************************/
 
+/* Only useful inside a macro to avoid compiler warning.
+ *
+ * Otherwise compiler might warn for "if (ptr)"
+ *   the address of ‘a’ will always evaluate as ‘true’ [-Werror=address]
+ *
+ * The trivial function avoids the compiler warning.
+ */
+static inline int
+_nm_is_null (const void *ptr)
+{
+	return !!ptr;
+}
+
+/*****************************************************************************/
+
 /* Determine whether @x is a power of two (@x being an integer type).
  * Basically, this returns TRUE, if @x has exactly one bit set.
  * For negative values and zero, this always returns FALSE. */
diff --git a/src/nm-ip4-config.h b/src/nm-ip4-config.h
index 4d42cee35a..b8019f3f6d 100644
--- a/src/nm-ip4-config.h
+++ b/src/nm-ip4-config.h
@@ -64,12 +64,12 @@ nm_ip_config_iter_ip4_route_next (NMDedupMultiIter *ipconf_iter, const NMPlatfor
 }
 
 #define nm_ip_config_iter_ip4_address_for_each(iter, self, address) \
-    for (({ if (address) { *((const NMPlatformIP4Address **) (address)) = NULL; } }), nm_ip_config_iter_ip4_address_init ((iter), (self)); \
+    for (({ if (!_nm_is_null (address)) { *((const NMPlatformIP4Address **) (address)) = NULL; } }), nm_ip_config_iter_ip4_address_init ((iter), (self)); \
          nm_ip_config_iter_ip4_address_next ((iter), (address)); \
          )
 
 #define nm_ip_config_iter_ip4_route_for_each(iter, self, route) \
-    for (({ if (route) { *((const NMPlatformIP4Route **) (route)) = NULL; } }), nm_ip_config_iter_ip4_route_init ((iter), (self)); \
+    for (({ if (!_nm_is_null (route)) { *((const NMPlatformIP4Route **) (route)) = NULL; } }), nm_ip_config_iter_ip4_route_init ((iter), (self)); \
          nm_ip_config_iter_ip4_route_next ((iter), (route)); \
          )
 
diff --git a/src/nm-ip6-config.h b/src/nm-ip6-config.h
index 9f798041a4..3b42d4960c 100644
--- a/src/nm-ip6-config.h
+++ b/src/nm-ip6-config.h
@@ -57,12 +57,12 @@ nm_ip_config_iter_ip6_route_next (NMDedupMultiIter *ipconf_iter, const NMPlatfor
 }
 
 #define nm_ip_config_iter_ip6_address_for_each(iter, self, address) \
-    for (({ if (address) { *(((const NMPlatformIP6Address **) address)) = NULL; } }), nm_ip_config_iter_ip6_address_init ((iter), (self)); \
+    for (({ if (!_nm_is_null (address)) { *(((const NMPlatformIP6Address **) address)) = NULL; } }), nm_ip_config_iter_ip6_address_init ((iter), (self)); \
          nm_ip_config_iter_ip6_address_next ((iter), (address)); \
          )
 
 #define nm_ip_config_iter_ip6_route_for_each(iter, self, route) \
-    for (({ if (route) { *((const NMPlatformIP6Route **) (route)) = NULL; } }), nm_ip_config_iter_ip6_route_init ((iter), (self)); \
+    for (({ if (!_nm_is_null (route)) { *((const NMPlatformIP6Route **) (route)) = NULL; } }), nm_ip_config_iter_ip6_route_init ((iter), (self)); \
          nm_ip_config_iter_ip6_route_next ((iter), (route)); \
          )