Fix pythonnondynamic feature for modern classes

Fixes nondynamic mode when an instance variable is set with the same
name as a class variable in a class derived from a SWIG proxy class.
The python_nondynamic testcase now works using -modern and testcase
enhanced slightly too.

Fixes #718

Examples/test-suite/python/python_nondynamic_runme.py

@@ -1,21 +1,41 @@
 import python_nondynamic
 
+def is_python_modern():
+    """Return True if SWIG is generating Python code using -modern. Works only if %python_nondynamic has been used."""
+    return hasattr(python_nondynamic, "_swig_setattr_nondynamic_class_variable")
+
+def debug_print(s):
+    show_debug = False
+    if show_debug:
+        print(s)
+
 aa = python_nondynamic.A()
 
 aa.a = 1
 aa.b = 2
+
+# Check values are really set
+if python_nondynamic.retrieve_A_a(aa) != 1: raise RuntimeError("a not set correctly")
+if python_nondynamic.retrieve_A_b(aa) != 2: raise RuntimeError("b not set correctly")
+
 try:
     aa.c = 2
-    err = 0
+    raise RuntimeError("A is not static")
-except:
+except AttributeError as e:
-    err = 1
+    debug_print(e)
-
+    pass
-if not err:
-    raise RuntimeError, "A is not static"
 
+class PurePythonClass(object):
+    def __init__(self):
+        self.variables = dict()
+    def __set__(self, name, value):
+        self.variables[name] = value
+    pass
 
 class B(python_nondynamic.A):
     c = 4
+    cc = PurePythonClass()
+    cc.nnn = "new attrib"
 
     def __init__(self):
         python_nondynamic.A.__init__(self)
@@ -23,26 +43,66 @@ class B(python_nondynamic.A):
     pass
 
 bb = B()
+bb.a = 4
+bb.b = 5
+# Check values are really set
+if python_nondynamic.retrieve_A_a(bb) != 4: raise RuntimeError("a not set correctly")
+if python_nondynamic.retrieve_A_b(bb) != 5: raise RuntimeError("b not set correctly")
 
 try:
     bb.c = 3
-    err = 0
+    print("bb.c = {}".format(bb.c))
-except:
+    print("B.c = {}".format(B.c))
-    err = 1
+    raise RuntimeError("B.c class variable messes up nondynamic-ness of B")
-
+except AttributeError as e:
-if not err:
+    debug_print(e)
-    print "bb.c = %d" % bb.c
+    pass
-    print "B.c = %d" % B.c
-    raise RuntimeError, "B.c class variable messes up nondynamic-ness of B"
 
 try:
     bb.d = 2
-    err = 0
+    raise RuntimeError("B is not static")
-except:
+except AttributeError as e:
-    err = 1
+    debug_print(e)
-
+    pass
-if not err:
-    raise RuntimeError, "B is not static"
 
 cc = python_nondynamic.C()
 cc.d = 3
+
+# An inconsistency between builtin and (non-builtin/modern).
+# Class variables cannot be set on builtin types, like other Python builtins, eg list.classvar=111 fails
+if python_nondynamic.is_python_builtin():
+    try:
+        python_nondynamic.C.classvar = 111
+        raise RuntimeError("C should not allow static variables to be added when using builtin")
+    except AttributeError as e:
+        debug_print(e)
+        pass
+else:
+    python_nondynamic.C.classvar = 111
+
+if is_python_modern():
+    # Not working with builtin or non-modern :(
+    try:
+        B.a = 10
+        raise RuntimeError("B should not allow adding a class variable by setting it as an instance variable")
+    except AttributeError as e:
+        debug_print(e)
+        pass
+
+    try:
+        python_nondynamic.A.a = 10
+        raise RuntimeError("A should not allow adding a class variable by setting it as an instance variable")
+    except AttributeError as e:
+        debug_print(e)
+        pass
+
+if not python_nondynamic.is_python_builtin():
+    try:
+        bb.cc = 3
+        print("bb.cc = {}".format(bb.cc))
+        print("B.cc = {}".format(B.cc))
+        raise RuntimeError("B.cc class variable messes up nondynamic-ness of B")
+    except AttributeError as e:
+        debug_print(e)
+        pass
+

Examples/test-suite/python_nondynamic.i

@@ -54,5 +54,14 @@
     int b;
   };
 
+  int retrieve_A_a(const struct A* self) { return self->a; }
+  int retrieve_A_b(const struct A* self) { return self->b; }
+%}
+%inline %{
+#ifdef SWIGPYTHON_BUILTIN
+int is_python_builtin() { return 1; }
+#else
+int is_python_builtin() { return 0; }
+#endif
 %}
 

Source/Modules/python.cxx

@@ -951,15 +951,32 @@ public:
 	}
       }
       if (modern) {
-	Printv(f_shadow,  "\n", "def _swig_setattr_nondynamic_method(set):\n", tab4, "def set_attr(self, name, value):\n",
+	Printv(f_shadow,  "\n", "def _swig_setattr_nondynamic_instance_variable(set):\n",
+	       tab4, "def set_instance_attr(self, name, value):\n",
 #ifdef USE_THISOWN
-	       tab4, tab4, "if hasattr(self, name) or (name in (\"this\", \"thisown\")):\n",
+	       tab4, tab4, "if name in (\"this\", \"thisown\"):\n",
+	       tab4, tab4, tab4, "set(self, name, value)\n",
 #else
-	       tab4, tab4, "if name == \"thisown\":\n", tab8, tab4, "return self.this.own(value)\n", tab4, tab4, "if hasattr(self, name) or (name == \"this\"):\n",
+	       tab4, tab4, "if name == \"thisown\":\n",
+	       tab4, tab4, tab4, "self.this.own(value)\n",
+	       tab4, tab4, "elif name == \"this\":\n",
+	       tab4, tab4, tab4, "set(self, name, value)\n",
 #endif
+	       tab4, tab4, "elif hasattr(self, name) and isinstance(getattr(type(self), name), property):\n",
 	       tab4, tab4, tab4, "set(self, name, value)\n",
 	       tab4, tab4, "else:\n",
-	       tab4, tab4, tab4, "raise AttributeError(\"You cannot add attributes to %s\" % self)\n", tab4, "return set_attr\n\n\n", NIL);
+	       tab4, tab4, tab4, "raise AttributeError(\"You cannot add instance attributes to %s\" % self)\n",
+	       tab4, "return set_instance_attr\n\n", NIL);
+
+	Printv(f_shadow,  "\n", "def _swig_setattr_nondynamic_class_variable(set):\n",
+	       tab4, "def set_class_attr(cls, name, value):\n",
+	       tab4, tab4, "if hasattr(cls, name) and not isinstance(getattr(cls, name), property):\n",
+	       tab4, tab4, tab4, "set(cls, name, value)\n",
+	       tab4, tab4, "else:\n",
+	       tab4, tab4, tab4, "raise AttributeError(\"You cannot add class attributes to %s\" % cls)\n",
+	       tab4, "return set_class_attr\n\n", NIL);
+
+	Printv(f_shadow, "\n", NIL);
       }
 
       if (directorsEnabled()) {
@@ -4535,8 +4552,8 @@ public:
 	  /* Add static attribute */
 	  if (GetFlag(n, "feature:python:nondynamic")) {
 	    Printv(f_shadow_file,
-		   tab4, "__setattr__ = _swig_setattr_nondynamic_method(object.__setattr__)\n",
+		   tab4, "__setattr__ = _swig_setattr_nondynamic_instance_variable(object.__setattr__)\n",
-		   tab4, "class __metaclass__(type):\n", tab4, tab4, "__setattr__ = _swig_setattr_nondynamic_method(type.__setattr__)\n", NIL);
+		   tab4, "class __metaclass__(type):\n", tab4, tab4, "__setattr__ = _swig_setattr_nondynamic_class_variable(type.__setattr__)\n", NIL);
 	  }
 	}
       }