Add checks for interface name symbol clashes

Source/Modules/csharp.cxx

@@ -2081,6 +2081,7 @@ public:
 
     if (proxy_flag) {
       proxy_class_name = NewString(Getattr(n, "sym:name"));
+      String *interface_name = Getattr(n, "feature:interface") ? Getattr(n, "interface:name") : 0;
       if (Node *outer = Getattr(n, "nested:outer")) {
 	String *outerClassesPrefix = Copy(Getattr(outer, "sym:name"));
 	for (outer = Getattr(outer, "nested:outer"); outer != 0; outer = Getattr(outer, "nested:outer")) {
@@ -2090,13 +2091,16 @@ public:
 	String *fnspace = nspace ? NewStringf("%s.%s", nspace, outerClassesPrefix) : outerClassesPrefix;
 	if (!addSymbol(proxy_class_name, n, fnspace))
 	  return SWIG_ERROR;
+	if (interface_name && !addInterfaceSymbol(interface_name, n, fnspace))
+	  return SWIG_ERROR;
 	if (nspace)
 	  Delete(fnspace);
 	Delete(outerClassesPrefix);
-      }
+      } else {
-      else {
 	if (!addSymbol(proxy_class_name, n, nspace))
 	  return SWIG_ERROR;
+	if (interface_name && !addInterfaceSymbol(interface_name, n, nspace))
+	  return SWIG_ERROR;
       }
 
       if (!nspace) {
@@ -2135,7 +2139,6 @@ public:
 
       if (Getattr(n, "feature:interface")) {
 	interface_class_code = NewString("");
-	String *interface_name = Getattr(n, "interface:name");
 	String *output_directory = outputDirectory(nspace);
 	f_interface = getOutputFile(output_directory, interface_name);
 	addOpenNamespace(nspace, f_interface);

Source/Modules/java.cxx

@@ -2136,17 +2136,21 @@ public:
 	}
       }
 
+      String *interface_name = Getattr(n, "feature:interface") ? Getattr(n, "interface:name") : 0;
       if (outerClassesPrefix) {
 	String *fnspace = nspace ? NewStringf("%s.%s", nspace, outerClassesPrefix) : outerClassesPrefix;
 	if (!addSymbol(proxy_class_name, n, fnspace))
 	  return SWIG_ERROR;
+	if (interface_name && !addInterfaceSymbol(interface_name, n, fnspace))
+	  return SWIG_ERROR;
 	if (nspace)
 	  Delete(fnspace);
 	Delete(outerClassesPrefix);
-      }
+      } else {
-      else {
 	if (!addSymbol(proxy_class_name, n, nspace))
 	  return SWIG_ERROR;
+	if (interface_name && !addInterfaceSymbol(interface_name, n, nspace))
+	  return SWIG_ERROR;
       }
 
       // Each outer proxy class goes into a separate file
@@ -2185,7 +2189,6 @@ public:
 
       if (Getattr(n, "feature:interface")) {
         interface_class_code = NewString("");
-	String *interface_name = Getattr(n, "interface:name");
 	String *output_directory = outputDirectory(nspace);
 	String *filen = NewStringf("%s%s.java", output_directory, interface_name);
 	f_interface = NewFile(filen, "w", SWIG_output_files());

Source/Modules/lang.cxx

@@ -3118,6 +3118,31 @@ int Language::addSymbol(const String *s, const Node *n, const_String_or_char_ptr
   return 1;
 }
 
+/* -----------------------------------------------------------------------------
+ * Language::addInterfaceSymbol()
+ *
+ * Adds a symbol entry into the target language symbol tables - for the interface
+ * feature only.
+ * Returns 1 if the symbol is added successfully.
+ * The scope is as per addSymbol.
+ * ----------------------------------------------------------------------------- */
+
+int Language::addInterfaceSymbol(const String *interface_name, Node *n, const_String_or_char_ptr scope) {
+  if (interface_name) {
+    Node *existing_symbol = symbolLookup(interface_name, scope);
+    if (existing_symbol) {
+      String *proxy_class_name = Getattr(n, "sym:name");
+      Swig_error(input_file, line_number, "The interface feature name '%s' for proxy class '%s' is already defined in the generated target language module in scope '%s'.\n",
+	  interface_name, proxy_class_name, scope);
+      Swig_error(Getfile(existing_symbol), Getline(existing_symbol), "Previous declaration of '%s'\n", interface_name);
+      return 0;
+    }
+    if (!addSymbol(interface_name, n, scope))
+      return 0;
+  }
+  return 1;
+}
+
 /* -----------------------------------------------------------------------------
  * Language::symbolAddScope()
  *
@@ -3214,7 +3239,7 @@ void Language::dumpSymbols() {
  * Language::symbolLookup()
  * ----------------------------------------------------------------------------- */
 
-Node *Language::symbolLookup(String *s, const_String_or_char_ptr scope) {
+Node *Language::symbolLookup(const String *s, const_String_or_char_ptr scope) {
   Hash *symbols = Getattr(symtabs, scope ? scope : "");
   if (!symbols) {
     return NULL;

Source/Modules/swigmod.h

@@ -208,8 +208,9 @@ public:
   /* Miscellaneous */
   virtual int validIdentifier(String *s);	/* valid identifier? */
   virtual int addSymbol(const String *s, const Node *n, const_String_or_char_ptr scope = "");	/* Add symbol        */
+  virtual int addInterfaceSymbol(const String *interface_name, Node *n, const_String_or_char_ptr scope = "");
   virtual void dumpSymbols();
-  virtual Node *symbolLookup(String *s, const_String_or_char_ptr scope = ""); /* Symbol lookup */
+  virtual Node *symbolLookup(const String *s, const_String_or_char_ptr scope = ""); /* Symbol lookup */
   virtual Hash* symbolAddScope(const_String_or_char_ptr scope);
   virtual Hash* symbolScopeLookup(const_String_or_char_ptr scope);
   virtual Hash* symbolScopePseudoSymbolLookup(const_String_or_char_ptr scope);