build: don't error on -Warray-bounds and -Wdangling-reference with GCC

kwvg · knst · kwvg · commit 9aab60b92eac · 2025-04-25T18:24:23.000Z
Currently, `-Warray-bounds` is triggered by `immer` code and
`-Wdangling-reference` is triggered by UniValue-adjacent code.

Co-authored-by: Konstantin Akimov &lt;knstqq@gmail.com&gt;
diff --git a/configure.ac b/configure.ac
@@ -452,6 +452,22 @@ if test "$enable_werror" = "yes"; then
   fi
   ERROR_CXXFLAGS=$CXXFLAG_WERROR
 
+  dnl -Warray-bounds and -Wdangling-reference cause problems with GCC. Do not treat these warnings as errors.
+  dnl Suppress -Warray-bounds entirely because of noisy output, currently unhappy with immer implementation.
+  AX_CHECK_COMPILE_FLAG([-Warray-bounds], [NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-array-bounds"], [], [$CXXFLAG_WERROR], [AC_LANG_SOURCE([
+    #if defined(__clang__) || defined(__INTEL_COMPILER) || !defined(__GNUC__)
+      #error Non-GCC compiler detected, not setting flag
+    #endif
+    int main(void) { return 0; }
+  ])])
+  dnl TODO: Remove suppression after backporting bitcoin#27605
+  AX_CHECK_COMPILE_FLAG([-Wdangling-reference], [NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-error=dangling-reference"], [], [$CXXFLAG_WERROR], [AC_LANG_SOURCE([
+    #if defined(__clang__) || defined(__INTEL_COMPILER) || !defined(__GNUC__)
+      #error Non-GCC compiler detected, not setting flag
+    #endif
+    int main(void) { return 0; }
+  ])])
+
   dnl -Wstringop-overread and -Wstringop-overflow are broken in gcc
   AX_CHECK_COMPILE_FLAG([-Wstringop-overread], [WARN_CXXFLAGS="$WARN_CXXFLAGS -Wno-stringop-overread"], [], [$CXXFLAG_WERROR])
   AX_CHECK_COMPILE_FLAG([-Wstringop-overflow], [WARN_CXXFLAGS="$WARN_CXXFLAGS -Wno-stringop-overflow"], [], [$CXXFLAG_WERROR])
