Python static method wrapper changes

- Static method wrappers were using the 'fastproxy' approach by default.
  This is inconsistent with instance method wrappers. The fastproxy approach
  is now turned off by default to be consistent with instance methods.
  Static method wrappers can now also be controlled using the -fastproxy and
  -olddefs options.

  Example:

    struct Klass {
      static int statmethod(int a = 2);
    };

  generates:

  class Klass(object):
      ...
      @staticmethod
      def statmethod(a=2):
          return _example.Klass_statmethod(a)

  instead of:

    class Klass(object):
      ...
      statmethod = staticmethod(_example.Klass_statmethod)

- Modernise wrappers for static methods to use decorator syntax - @staticmethod.

- Add missing runtime test for static class methods and using the actual
  class method.

CHANGES.current

@@ -7,6 +7,41 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.0 (in progress)
 ===========================
 
+2019-01-16: wsfulton
+            Python static method wrapper changes
+
+            - Static method wrappers were using the 'fastproxy' approach by default.
+              This is inconsistent with instance method wrappers. The fastproxy approach
+              is now turned off by default to be consistent with instance methods.
+              Static method wrappers can now also be controlled using the -fastproxy and
+              -olddefs options.
+
+              Example:
+
+                struct Klass {
+                  static int statmethod(int a = 2);
+                };
+
+              generates by default:
+
+              class Klass(object):
+                  ...
+                  @staticmethod
+                  def statmethod(a=2):
+                      return _example.Klass_statmethod(a)
+
+              instead of the following (which can be restored by using -fastproxy):
+
+                class Klass(object):
+                  ...
+                  statmethod = staticmethod(_example.Klass_statmethod)
+
+
+- Modernise wrappers for static methods to use decorator syntax - @staticmethod.
+
+- Add missing runtime test for static class methods and using the actual class method.
+
+
 2019-01-12: ZackerySpytz
             [OCaml] #1403 #1194 Fix compilation problems for OCaml >= 4.03.0 due to OCaml using
             int64_t instead of int64.

Examples/test-suite/python/callback_runme.py

@@ -13,6 +13,9 @@ if foobar(3, _callback.foo) != foo(3):
 if foobar(3, foo) != foo(3):
     raise RuntimeError
 
+if foobar(3, A.bar) != A.bar(3):
+    raise RuntimeError
+
 if foobar(3, A_bar) != A_bar(3):
     raise RuntimeError
 

Source/Modules/python.cxx

@@ -4637,10 +4637,12 @@ public:
     }
 
     if (shadow) {
-      if (!Getattr(n, "feature:python:callback") && have_addtofunc(n)) {
+      bool fast = (fastproxy && !have_addtofunc(n)) || Getattr(n, "feature:callback");
+      if (!fast || olddefs) {
 	int kw = (check_kwargs(n) && !Getattr(n, "sym:overloaded")) ? 1 : 0;
 	String *parms = make_pyParmList(n, false, false, kw);
 	String *callParms = make_pyParmList(n, false, true, kw);
+	Printv(f_shadow, "\n", tab4, "@staticmethod", NIL);
 	Printv(f_shadow, "\n", tab4, "def ", symname, "(", parms, ")", returnTypeAnnotation(n), ":\n", NIL);
 	if (have_docstring(n))
 	  Printv(f_shadow, tab8, docstring(n, AUTODOC_STATICFUNC, tab8), "\n", NIL);
@@ -4649,12 +4651,14 @@ public:
 	if (have_pythonappend(n)) {
 	  Printv(f_shadow, tab8, "val = ", funcCall(Swig_name_member(NSPACE_TODO, class_name, symname), callParms), "\n", NIL);
 	  Printv(f_shadow, indent_pythoncode(pythonappend(n), tab8, Getfile(n), Getline(n), "%pythonappend or %feature(\"pythonappend\")"), "\n", NIL);
-	  Printv(f_shadow, tab8, "return val\n\n", NIL);
+	  Printv(f_shadow, tab8, "return val\n", NIL);
 	} else {
-	  Printv(f_shadow, tab8, "return ", funcCall(Swig_name_member(NSPACE_TODO, class_name, symname), callParms), "\n\n", NIL);
+	  Printv(f_shadow, tab8, "return ", funcCall(Swig_name_member(NSPACE_TODO, class_name, symname), callParms), "\n", NIL);
 	}
-	Printv(f_shadow, tab4, symname, " = staticmethod(", symname, ")\n", NIL);
-      } else {
+      }
+
+      // Below may result in a 2nd definition of the method when -olddefs is used. The Python interpreter will use the second definition as it overwrites the first.
+      if (fast) {
 	Printv(f_shadow, tab4, symname, " = staticmethod(", module, ".", Swig_name_member(NSPACE_TODO, class_name, symname),
 	       ")\n", NIL);
       }