Fix -Wunused-variable warning in Lua and Octave wrappers

Add bool output parameter to Swig_overload_dispatch to say when it has
generated code that will use the typecheck typemap code to help Lua and
Octave to not emit unused argv[] arrays.

Alas, resorted to warning suppression for deficient cpp11_initializer_list
typecheck typemap in cpp11_std_initializer_list testcase.

Examples/test-suite/cpp11_attribute_specifiers.i

@@ -12,7 +12,6 @@
 #endif
 
 #if defined(__clang__)
-#pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
 #pragma clang diagnostic ignored "-Wattributes"
 #pragma clang diagnostic ignored "-Wunused-variable"

Examples/test-suite/cpp11_initializer_list.i

@@ -18,6 +18,19 @@
 #endif
 %}
 
+#if defined(SWIGLUA) || defined(SWIGOCTAVE)
+%{
+// The empty typecheck typemap for std::initializer_list results in $input not being used and a resulting unused variable warning
+#if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wunused-variable"
+#elif defined(__clang__)
+#pragma clang diagnostic ignored "-Wunused-variable"
+#elif defined(_MSC_VER)
+#pragma warning(disable : 4990)
+#endif
+%}
+#endif
+
 %inline %{
 #include <initializer_list>
 #include <string>

Source/Modules/guile.cxx

@@ -951,7 +951,8 @@ public:
 	/* Emit overloading dispatch function */
 
 	int maxargs;
-	String *dispatch = Swig_overload_dispatch(n, "return %s(argc,argv);", &maxargs);
+	bool check_emitted = false;
+	String *dispatch = Swig_overload_dispatch(n, "return %s(argc,argv);", &maxargs, &check_emitted);
 
 	/* Generate a dispatch wrapper for all overloaded functions */
 

Source/Modules/lua.cxx

@@ -839,8 +839,9 @@ public:
     /* Last node in overloaded chain */
 
     int maxargs;
+    bool check_emitted = false;
     String *tmp = NewString("");
-    String *dispatch = Swig_overload_dispatch(n, "return %s(L);", &maxargs);
+    String *dispatch = Swig_overload_dispatch(n, "return %s(L);", &maxargs, &check_emitted);
 
     /* Generate a dispatch wrapper for all overloaded functions */
 
@@ -861,12 +862,14 @@ public:
 
     Printv(f->def, "static int ", wname, "(lua_State* L) {", NIL);
     Wrapper_add_local(f, "argc", "int argc");
-    Printf(tmp, "int argv[%d]={1", maxargs + 1);
+    if (maxargs > 0 && check_emitted) {
-    for (int i = 1; i <= maxargs; i++) {
+      Printf(tmp, "int argv[%d]={1", maxargs + 1);
-      Printf(tmp, ",%d", i + 1);
+      for (int i = 1; i <= maxargs; i++) {
+	Printf(tmp, ",%d", i + 1);
+      }
+      Printf(tmp, "}");
+      Wrapper_add_local(f, "argv", tmp);
     }
-    Printf(tmp, "}");
-    Wrapper_add_local(f, "argv", tmp);
     Printf(f->code, "argc = lua_gettop(L);\n");
 
     Replaceall(dispatch, "$args", "self,args");

Source/Modules/ocaml.cxx

@@ -703,10 +703,9 @@ public:
     if (isOverloaded) {
       if (!Getattr(n, "sym:nextSibling")) {
 	int maxargs;
+	bool check_emitted = false;
 	Wrapper *df = NewWrapper();
-	String *dispatch = Swig_overload_dispatch(n,
+	String *dispatch = Swig_overload_dispatch(n, "free(argv);\n" "CAMLreturn(%s(args));\n", &maxargs, &check_emitted);
-						  "free(argv);\n" "CAMLreturn(%s(args));\n",
-						  &maxargs);
 
 	Wrapper_add_local(df, "argv", "value *argv");
 

Source/Modules/octave.cxx

@@ -796,12 +796,13 @@ public:
     String *iname = Getattr(n, "sym:name");
     String *wname = Swig_name_wrapper(iname);
     int maxargs;
-    String *dispatch = Swig_overload_dispatch(n, "return %s(args, nargout);", &maxargs);
+    bool check_emitted = false;
+    String *dispatch = Swig_overload_dispatch(n, "return %s(args, nargout);", &maxargs, &check_emitted);
     String *tmp = NewString("");
 
     Octave_begin_function(n, f->def, iname, wname, true);
     Wrapper_add_local(f, "argc", "int argc = args.length()");
-    if (maxargs > 0) {
+    if (maxargs > 0 && check_emitted) {
       Printf(tmp, "octave_value_ref argv[%d]={", maxargs);
       for (int j = 0; j < maxargs; ++j)
 	Printf(tmp, "%soctave_value_ref(args,%d)", j ? "," : " ", j);

Source/Modules/overload.cxx

@@ -360,9 +360,9 @@ List *Swig_overload_rank(Node *n, bool script_lang_wrapping) {
   return result;
 }
 
-// /* -----------------------------------------------------------------------------
+/* -----------------------------------------------------------------------------
-//  * print_typecheck()
+ * print_typecheck()
-//  * ----------------------------------------------------------------------------- */
+ * ----------------------------------------------------------------------------- */
 
 static bool print_typecheck(String *f, int j, Parm *pj, bool implicitconvtypecheckoff) {
   char tmp[256];
@@ -425,10 +425,11 @@ static String *ReplaceFormat(const_String_or_char_ptr fmt, int j) {
 /*
   Cast dispatch mechanism.
 */
-String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *maxargs) {
+String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *maxargs, bool *check_emitted) {
   int i, j;
 
   *maxargs = 0;
+  *check_emitted = false;
 
   String *f = NewString("");
   String *sw = NewString("");
@@ -533,6 +534,7 @@ String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *
 	  }
 
 	  if (emitcheck) {
+	    *check_emitted = true;
 	    if (need_v) {
 	      Printf(f, "int _v = 0;\n");
 	      need_v = 0;
@@ -612,10 +614,11 @@ String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *
 /*
   Fast dispatch mechanism, provided by  Salvador Fandi~no Garc'ia (#930586).
 */
-static String *overload_dispatch_fast(Node *n, const_String_or_char_ptr fmt, int *maxargs, const_String_or_char_ptr fmt_fastdispatch) {
+static String *overload_dispatch_fast(Node *n, const_String_or_char_ptr fmt, int *maxargs, bool *check_emitted, const_String_or_char_ptr fmt_fastdispatch) {
   int i, j;
 
   *maxargs = 0;
+  *check_emitted = false;
 
   String *f = NewString("");
 
@@ -713,6 +716,7 @@ static String *overload_dispatch_fast(Node *n, const_String_or_char_ptr fmt, int
 	  }
 
 	  if (emitcheck) {
+	    *check_emitted = true;
 	    if (need_v) {
 	      Printf(f, "int _v = 0;\n");
 	      need_v = 0;
@@ -775,15 +779,16 @@ static String *overload_dispatch_fast(Node *n, const_String_or_char_ptr fmt, int
   return f;
 }
 
-String *Swig_overload_dispatch(Node *n, const_String_or_char_ptr fmt, int *maxargs, const_String_or_char_ptr fmt_fastdispatch) {
+String *Swig_overload_dispatch(Node *n, const_String_or_char_ptr fmt, int *maxargs, bool *check_emitted, const_String_or_char_ptr fmt_fastdispatch) {
 
   if (fast_dispatch_mode || GetFlag(n, "feature:fastdispatch")) {
-    return overload_dispatch_fast(n, fmt, maxargs, fmt_fastdispatch);
+    return overload_dispatch_fast(n, fmt, maxargs, check_emitted, fmt_fastdispatch);
   }
 
   int i, j;
 
   *maxargs = 0;
+  *check_emitted = false;
 
   String *f = NewString("");
 
@@ -824,6 +829,7 @@ String *Swig_overload_dispatch(Node *n, const_String_or_char_ptr fmt, int *maxar
 	pj = Getattr(pj, "tmap:in:next");
 	continue;
       }
+      *check_emitted = true;
       if (j >= num_required) {
 	String *lfmt = ReplaceFormat(fmt, num_arguments);
 	Printf(f, "if (%s <= %d) {\n", argc_template_string, j);

Source/Modules/perl5.cxx

@@ -908,7 +908,8 @@ public:
     } else if (!Getattr(n, "sym:nextSibling")) {
       /* Generate overloaded dispatch function */
       int maxargs;
-      String *dispatch = Swig_overload_dispatch_cast(n, "PUSHMARK(MARK); SWIG_CALLXS(%s); return;", &maxargs);
+      bool check_emitted = false;
+      String *dispatch = Swig_overload_dispatch_cast(n, "PUSHMARK(MARK); SWIG_CALLXS(%s); return;", &maxargs, &check_emitted);
 
       /* Generate a dispatch wrapper for all overloaded functions */
 

Source/Modules/php.cxx

@@ -1004,8 +1004,9 @@ public:
     /* Last node in overloaded chain */
 
     int maxargs;
+    bool check_emitted = false;
     String *tmp = NewStringEmpty();
-    String *dispatch = Swig_overload_dispatch(n, "%s(INTERNAL_FUNCTION_PARAM_PASSTHRU); return;", &maxargs);
+    String *dispatch = Swig_overload_dispatch(n, "%s(INTERNAL_FUNCTION_PARAM_PASSTHRU); return;", &maxargs, &check_emitted);
 
     /* Generate a dispatch wrapper for all overloaded functions */
 

Source/Modules/python.cxx

@@ -2580,6 +2580,7 @@ public:
     bool add_self = builtin_self && (!builtin_ctor || director_class);
 
     int maxargs;
+    bool check_emitted = false;
 
     String *tmp = NewString("");
     String *dispatch;
@@ -2588,7 +2589,7 @@ public:
     String *dispatch_code = NewStringf("return %s", dispatch_call);
 
     if (castmode) {
-      dispatch = Swig_overload_dispatch_cast(n, dispatch_code, &maxargs);
+      dispatch = Swig_overload_dispatch_cast(n, dispatch_code, &maxargs, &check_emitted);
     } else {
       String *fastdispatch_code;
       if (builtin_ctor)
@@ -2599,7 +2600,7 @@ public:
 	Insert(fastdispatch_code, 0, "{\n");
 	Append(fastdispatch_code, "\n}");
       }
-      dispatch = Swig_overload_dispatch(n, dispatch_code, &maxargs, fastdispatch_code);
+      dispatch = Swig_overload_dispatch(n, dispatch_code, &maxargs, &check_emitted, fastdispatch_code);
       Delete(fastdispatch_code);
     }
 

Source/Modules/ruby.cxx

@@ -2043,8 +2043,9 @@ public:
     /* Last node in overloaded chain */
 
     int maxargs;
+    bool check_emitted = false;
     String *tmp = NewString("");
-    String *dispatch = Swig_overload_dispatch(n, "return %s(nargs, args, self);", &maxargs);
+    String *dispatch = Swig_overload_dispatch(n, "return %s(nargs, args, self);", &maxargs, &check_emitted);
 
     /* Generate a dispatch wrapper for all overloaded functions */
 

Source/Modules/scilab.cxx

@@ -571,9 +571,10 @@ public:
     String *functionName = Getattr(node, "sym:name");
     String *wrapperName = Swig_name_wrapper(functionName);
     int maxargs = 0;
+    bool check_emitted = false;
 
     /* Generate the dispatch function */
-    String *dispatch = Swig_overload_dispatch(node, "return %s(SWIG_GatewayArguments);", &maxargs);
+    String *dispatch = Swig_overload_dispatch(node, "return %s(SWIG_GatewayArguments);", &maxargs, &check_emitted);
     String *tmp = NewString("");
 
     Printv(wrapper->def, "SWIGEXPORT int ", wrapperName, "(SWIG_GatewayParameters) {\n", NIL);

Source/Modules/swigmod.h

@@ -388,8 +388,8 @@ void emit_mark_varargs(ParmList *l);
 String *emit_action(Node *n);
 int emit_action_code(Node *n, String *wrappercode, String *action);
 void Swig_overload_check(Node *n);
-String *Swig_overload_dispatch(Node *n, const_String_or_char_ptr fmt, int *, const_String_or_char_ptr fmt_fastdispatch = 0);
+String *Swig_overload_dispatch(Node *n, const_String_or_char_ptr fmt, int *maxargs, bool *check_emitted, const_String_or_char_ptr fmt_fastdispatch = 0);
-String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *);
+String *Swig_overload_dispatch_cast(Node *n, const_String_or_char_ptr fmt, int *maxargs, bool *check_emitted);
 List *Swig_overload_rank(Node *n, bool script_lang_wrapping);
 SwigType *cplus_value_type(SwigType *t);
 

Source/Modules/tcl8.cxx

@@ -500,7 +500,8 @@ public:
 	/* Emit overloading dispatch function */
 
 	int maxargs;
-	String *dispatch = Swig_overload_dispatch(n, "return %s(clientData, interp, objc, argv - 1);", &maxargs);
+	bool check_emitted = false;
+	String *dispatch = Swig_overload_dispatch(n, "return %s(clientData, interp, objc, argv - 1);", &maxargs, &check_emitted);
 
 	/* Generate a dispatch wrapper for all overloaded functions */