Improve typemap method and attribute checking

Specifying a value on the typemap method now gives an error, e.g.:

%typemap(argout=123) char * ""

The old way of specifying a language name in the typemap attributes
is no longer supported (it has been deprecated for 16 years).

Closes #891

CHANGES.current

@@ -7,6 +7,14 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.1.0 (in progress)
 ===========================
 
+2022-03-03: olly
+	    #891 Report errors for typemap attributes without a value
+	    (previously SWIG segfaulted) and for typemap types with a value
+	    (previously the value was quietly ignored).
+
+	    The old way of specifying a language name in the typemap attributes
+	    is no longer supported (it has been deprecated for 16 years).
+
 2022-03-02: geographika, wsfulton
             [Python] #1951 Add Python variable annotations support.
 
@@ -38,10 +46,6 @@ Version 4.1.0 (in progress)
 
             *** POTENTIAL INCOMPATIBILITY ***
 
-2022-03-02: olly
-	    #891 Give error for typemap argument without a value.  Previously
-	    SWIG segfaulted.
-
 2022-02-27: wsfulton
             [Python] #735 #1561 Function annotations containing C/C++ types are no longer
             generated when using the -py3 option. Function annotations support has been

Doc/Manual/Typemaps.html

@@ -3298,7 +3298,7 @@ The example above also shows a common approach of issuing a warning for an as ye
 </p>
 
 <p>
-<b>Compatibility note: </b> In SWIG-1.1 different languages could be distinguished with the language name being put within the <tt>%typemap</tt> directive, for example, <br>
+<b>Compatibility note: </b> In SWIG-1.1 different languages could be distinguished with the language name being put within the <tt>%typemap</tt> directive, but this was deprecated in SWIG 1.3.28 and support finally dropped completely in SWIG 4.1.0 so you'll need to update any remaining uses to use the approach above.  For example, <br>
 <tt>%typemap(ruby, in) int "$1 = NUM2INT($input);"</tt>.
 </p>
 

Examples/test-suite/errors/swig_typemap_missing_value.i

@@ -1,6 +1,7 @@
 %module xxx
 
 %typemap(in, numinputs=1, foo) int ""
+%typemap(argout=123) char* ""
 
-/* SWIG segfaulted trying to use the above typemap in SWIG < 4.1.0. */
+/* SWIG segfaulted trying to use the above in typemap in SWIG < 4.1.0. */
 void func(int arg);

Examples/test-suite/errors/swig_typemap_missing_value.stderr

@@ -1 +1,2 @@
-swig_typemap_missing_value.i:3: Error: %typemap argument 'foo' is missing value
+swig_typemap_missing_value.i:3: Error: %typemap attribute 'foo' is missing its value.  If this is specifying the target language, that's no longer supported: use #ifdef SWIG<LANG> instead.
+swig_typemap_missing_value.i:4: Error: %typemap method shouldn't have a value specified.

Source/CParse/parser.y

@@ -2725,27 +2725,17 @@ typemap_directive :  TYPEMAP LPAREN typemap_type RPAREN tm_list stringbrace {
 typemap_type   : kwargs {
 		 String *name = Getattr($1, "name");
 		 Hash *p = nextSibling($1);
-		 if (p && (!Getattr(p,"value"))) {
- 		   /* this is the deprecated two argument typemap form */
- 		   Swig_warning(WARN_DEPRECATED_TYPEMAP_LANG,cparse_file, cparse_line,
-				"Specifying the language name in %%typemap is deprecated - use #ifdef SWIG<LANG> instead.\n");
-		   /* two argument typemap form */
-		   if (!name || (Strcmp(name,typemap_lang))) {
-		     name = 0;
-		     p = 0;
-		   } else {
-		     name = Getattr(p,"name");
-		     p = nextSibling(p);
-		   }
-		 } else {
-		   /* one-argument typemap-form */
-		 }
 		 $$.method = name;
 		 $$.kwargs = p;
+		 if (Getattr($1, "value")) {
+		   Swig_error(cparse_file, cparse_line,
+			      "%%typemap method shouldn't have a value specified.\n");
+		 }
 		 while (p) {
 		   if (!Getattr(p, "value")) {
 		     Swig_error(cparse_file, cparse_line,
-				"%%typemap argument '%s' is missing value\n", Getattr(p, "name"));
+				"%%typemap attribute '%s' is missing its value.  If this is specifying the target language, that's no longer supported: use #ifdef SWIG<LANG> instead.\n",
+				Getattr(p, "name"));
 		     /* Set to empty value to avoid segfaults later. */
 		     Setattr(p, "value", NewStringEmpty());
 		   }

Source/Include/swigwarn.h

@@ -52,7 +52,7 @@
 #define WARN_DEPRECATED_NAME          121
 #define WARN_DEPRECATED_NOEXTERN      122
 #define WARN_DEPRECATED_NODEFAULT     123
-#define WARN_DEPRECATED_TYPEMAP_LANG  124
+/* Unused since 4.1.0: #define WARN_DEPRECATED_TYPEMAP_LANG  124 */
 #define WARN_DEPRECATED_INPUT_FILE    125
 #define WARN_DEPRECATED_NESTED_WORKAROUND 126