Make method wrappers suffix optional and disabled by default

Unfortunately the changes of 26bf86322 (Use SWIG-specific for
non-overloaded synthesized functions too, 2021-11-09) did break some
existing code bases using SWIG as they hardcoded the old wrapper
function names.

So turn this off by default and add a global variable allowing to enable
this, which can be done for a specific language only. This is ugly but,
unfortunately, there is no way to use the Language object from the C
function Swig_MethodToFunction(), so the only alternative would be to
add another parameter to it, but it already has 6 of them, so it
wouldn't really be that much better.

See #2366, #2368, #2370.

3 files changed, 12 insertions, 4 deletions

diff --git a/Source/Modules/lang.cxx b/Source/Modules/lang.cxx
index eb61752b8..4abb6b8b5 100644
--- a/Source/Modules/lang.cxx
+++ b/Source/Modules/lang.cxx
@@ -77,6 +77,9 @@ static Hash *classhash;
 extern int GenerateDefault;
 extern int ForceExtern;
 extern int AddExtern;
+extern "C" {
+  extern int UseWrapperSuffix;
+}
 
 /* import modes */
 
@@ -1324,7 +1327,7 @@ int Language::staticmemberfunctionHandler(Node *n) {
       // See Swig_MethodToFunction() for the explanation of this code.
       if (Getattr(n, "sym:overloaded")) {
 	Append(cname, Getattr(defaultargs ? defaultargs : n, "sym:overname"));
-      } else {
+      } else if (UseWrapperSuffix) {
 	Append(cname, "__SWIG");
       }
 
diff --git a/Source/Modules/main.cxx b/Source/Modules/main.cxx
index 9344a7299..44d30e893 100644
--- a/Source/Modules/main.cxx
+++ b/Source/Modules/main.cxx
@@ -37,6 +37,9 @@ int Verbose = 0;
 int AddExtern = 0;
 int NoExcept = 0;
 int SwigRuntime = 0;		// 0 = no option, 1 = -runtime, 2 = -noruntime
+extern "C" {
+  int UseWrapperSuffix = 0;	// If 1, append suffix to non-overloaded functions too.
+}
 
 /* Suppress warning messages for private inheritance, preprocessor evaluation etc...
    WARN_PP_EVALUATION                           202
diff --git a/Source/Swig/cwrap.c b/Source/Swig/cwrap.c
index 36e69332c..3b20f4e4f 100644
--- a/Source/Swig/cwrap.c
+++ b/Source/Swig/cwrap.c
@@ -15,6 +15,8 @@
 #include "swig.h"
 #include "cparse.h"
 
+extern int UseWrapperSuffix; // from main.cxx
+
 static const char *cresult_variable_name = "result";
 
 static Parm *nonvoid_parms(Parm *p) {
@@ -1083,13 +1085,13 @@ int Swig_MethodToFunction(Node *n, const_String_or_char_ptr nspace, String *clas
        in C.
 
        But when not using the suffix used for overloaded functions, we still need to ensure that the
-       wrapper name doesn't conflict with any wrapper functions, so make it sufficiently unique by
-       appending a suffix similar to the one used for overloaded functions to it.
+       wrapper name doesn't conflict with any wrapper functions for some languages, so optionally make
+       it sufficiently unique by appending a suffix similar to the one used for overloaded functions to it.
      */
     if (code) {
       if (Getattr(n, "sym:overloaded")) {
 	Append(mangled, Getattr(defaultargs ? defaultargs : n, "sym:overname"));
-      } else {
+      } else if (UseWrapperSuffix) {
 	Append(mangled, "__SWIG");
       }
     }