Use SWIG_NOEXCEPT for deprecated dynamic exception specifications

SWIG_NOEXCEPT is generated instead of throw() which is deprecated in
c++11. If c++11 or later is being used, then this macro expands to
noexcept instead of throw().

Affects director code only.

Also fix up some testcase to not use throw() when using c++11 or later.
Tested with clang and -Wdeprecated-dynamic-exception-spec as gcc
doesn't seem to warn for this deprecation.

Closes #3027

CHANGES.current

@@ -7,6 +7,12 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.4.0 (in progress)
 ===========================
 
+2025-04-29: r-barnes, wsfulton
+            #3027 Remove generation of empty dynamic exception specifications - throw(),
+            which are deprecated in c++11. This was only when using the director feature.
+            A new macro SWIG_NOEXCEPT is used which ensures that throw() or noexcept is
+            used for the appropriate C++ standard that the compiler is compiling for.
+
 2025-04-28: jschueller, henryiii
             [Python] #2967 Use __spec__.parent as the first approach to obtaining
             a module's package name when importing the low-level C/C++ module as the

Examples/test-suite/cpp11_default_delete.i

@@ -107,11 +107,11 @@ struct moveonly {
 };
 
 struct ConstructorThrow {
-  ConstructorThrow() throw() = default;
-  ConstructorThrow(const ConstructorThrow&) throw() = delete;
-  ConstructorThrow(ConstructorThrow&&) throw() = delete;
-  ConstructorThrow& operator=(const ConstructorThrow&) throw() = delete;
-  ~ConstructorThrow() throw() = default;
+  ConstructorThrow() noexcept = default;
+  ConstructorThrow(const ConstructorThrow&) noexcept = delete;
+  ConstructorThrow(ConstructorThrow&&) noexcept = delete;
+  ConstructorThrow& operator=(const ConstructorThrow&) noexcept = delete;
+  ~ConstructorThrow() noexcept = default;
 };
 
 %}

Examples/test-suite/director_exception_nothrow.i

@@ -5,8 +5,8 @@
 %feature("director") Bar;
 
 %{
-#if defined(_MSC_VER)
-  #pragma warning(disable: 4290) // C++ exception specification ignored except to indicate a function is not __declspec(nothrow)
+#if defined(__cplusplus) && __cplusplus >=201103L
+#define throw() noexcept
 #endif
 %}
 

Lib/csharp/director.swg

@@ -28,10 +28,10 @@ namespace Swig {
     DirectorException(const std::string &msg) : swig_msg(msg) {
     }
 
-    virtual ~DirectorException() throw() {
+    virtual ~DirectorException() SWIG_NOEXCEPT {
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return swig_msg.c_str();
     }
   };

Lib/d/director.swg

@@ -26,10 +26,10 @@ namespace Swig {
     DirectorException(const std::string &msg) : swig_msg(msg) {
     }
 
-    virtual ~DirectorException() throw() {
+    virtual ~DirectorException() SWIG_NOEXCEPT {
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return swig_msg.c_str();
     }
   };

Lib/java/director.swg

@@ -428,12 +428,12 @@ namespace Swig {
     DirectorException(const char *msg) : jenv_(SWIG_NULLPTR), throwable_(SWIG_NULLPTR), classname_(SWIG_NULLPTR), msg_(msg ? copystr(msg) : SWIG_NULLPTR) {
     }
 
-    ~DirectorException() throw() {
+    ~DirectorException() SWIG_NOEXCEPT {
       delete[] classname_;
       delete[] msg_;
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return msg_ ? msg_ : "Unspecified DirectorException message";
     }
 

Lib/ocaml/director.swg

@@ -20,10 +20,10 @@ namespace Swig {
       DirectorException(const char *msg="") : swig_msg(msg) {
       }
 
-      virtual ~DirectorException() throw() {
+      virtual ~DirectorException() SWIG_NOEXCEPT {
       }
 
-      const char *what() const throw() {
+      const char *what() const SWIG_NOEXCEPT {
         return swig_msg.c_str();
       }
   };

Lib/perl5/director.swg

@@ -151,7 +151,7 @@ namespace Swig {
       SvREFCNT_inc(err);
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return SvPV_nolen(err);
     }
 
@@ -172,10 +172,10 @@ namespace Swig {
     }
 
   public:
-    virtual ~DirectorWrapException() throw() {
+    virtual ~DirectorWrapException() SWIG_NOEXCEPT {
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return msg.c_str();
     }
 

Lib/php/director.swg

@@ -136,10 +136,10 @@ namespace Swig {
       if (!EG(exception)) zend_throw_exception(NULL, swig_msg.c_str(), code);
     }
 
-    virtual ~DirectorException() throw() {
+    virtual ~DirectorException() SWIG_NOEXCEPT {
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return swig_msg.c_str();
     }
 

Lib/python/director.swg

@@ -177,7 +177,7 @@ namespace Swig {
       SWIG_PYTHON_THREAD_END_BLOCK;
     }
 
-    virtual ~DirectorException() throw() {
+    virtual ~DirectorException() SWIG_NOEXCEPT {
     }
 
     /* Deprecated, use what() instead */
@@ -185,7 +185,7 @@ namespace Swig {
       return what();
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return swig_msg.c_str();
     }
 

Lib/ruby/director.swg

@@ -132,7 +132,7 @@ namespace Swig {
     }
 
   public:
-    virtual ~DirectorException() throw() {
+    virtual ~DirectorException() SWIG_NOEXCEPT {
     }
 
     VALUE getType() const {
@@ -148,7 +148,7 @@ namespace Swig {
       return swig_msg;
     }
 
-    const char *what() const throw() {
+    const char *what() const SWIG_NOEXCEPT {
       return swig_msg.c_str();
     }
   };

Lib/swiglabels.swg

@@ -124,6 +124,8 @@
 
 #if defined(__cplusplus) && __cplusplus >=201103L
 # define SWIG_NULLPTR nullptr
+# define SWIG_NOEXCEPT noexcept
 #else
 # define SWIG_NULLPTR NULL
+# define SWIG_NOEXCEPT throw()
 #endif 

Source/Modules/lang.cxx

@@ -2191,7 +2191,10 @@ int Language::classDirectorDestructor(Node *n) {
    */
   File *f_directors = Swig_filebyname("director");
   File *f_directors_h = Swig_filebyname("director_h");
-  if (Getattr(n, "throw")) {
+  if (Getattr(n, "noexcept")) {
+    Printf(f_directors_h, "    virtual ~%s() noexcept;\n", DirectorClassName);
+    Printf(f_directors, "%s::~%s() noexcept {\n}\n\n", DirectorClassName, DirectorClassName);
+  } else if (Getattr(n, "throw")) {
     Printf(f_directors_h, "    virtual ~%s() throw();\n", DirectorClassName);
     Printf(f_directors, "%s::~%s() throw() {\n}\n\n", DirectorClassName, DirectorClassName);
   } else {