Small update for pydrivers: force reloading the pydrivers.py Blender

text module when user edits the input text box of any pydriver
(Transform Properties panel, Ipo window).

It's enough to click in and out of a single pydriver's text input box
for the module reloading and also re-evaluation of all pydrivers
available. Maybe this "refreshing" should also be available from a
menu, let's see.

Note for Python fans:

Definitions and redefinitions in a reloaded module are properly handled
in Python, but previously defined data in the module doesn't disappear.
So if you define a function "f" inside a module, import it, then change
the function's name to "g" and reload the module, both "f" and "g" will
be available. This is considered a feature, check reload's documentation:
http://docs.python.org/lib/built-in-funcs.html#l2h-59

source/blender/blenkernel/BKE_bad_level_calls.h

@@ -67,10 +67,10 @@ void BPY_do_pyscript (struct ID *id, short int event);
 void BPY_clear_script (struct Script *script);
 void BPY_free_compiled_text (struct Text *text);
 void BPY_free_screen_spacehandlers (struct bScreen *sc);
-/* ipo.c: */
-float BPY_pydriver_eval(struct IpoDriver *driver);
-/* depsgraph.c: */
+/* pydrivers */
 struct Object **BPY_pydriver_get_objects(struct IpoDriver *driver);
+float BPY_pydriver_eval(struct IpoDriver *driver);
+void BPY_pydriver_update(void);
 
 /* writefile.c */
 struct Oops;

source/blender/blenkernel/bad_level_call_stubs/stubs.c

@@ -109,6 +109,7 @@ void BPY_do_pyscript(ID *id, short int event){}
 void BPY_clear_script(Script *script){}
 void BPY_free_compiled_text(struct Text *text){}
 void BPY_free_screen_spacehandlers (struct bScreen *sc){}
+void BPY_pydriver_update(void){}
 float BPY_pydriver_eval(struct IpoDriver *driver)
 {
 	return 0;

source/blender/python/BPY_extern.h

@@ -81,6 +81,7 @@ extern "C" {
 	int BPY_do_spacehandlers(struct ScrArea *sa, unsigned short event,
 		unsigned short space_event);
 
+	void BPY_pydriver_update(void);
 	float BPY_pydriver_eval(struct IpoDriver *driver);
 	struct Object **BPY_pydriver_get_objects(struct IpoDriver *driver);
 

source/blender/python/BPY_interface.c

@@ -1021,6 +1021,7 @@ static float pydriver_error(IpoDriver *driver) {
 		bpy_pydriver_freeList();
 
 	if (bpy_pydriver_Dict) { /* free the global dict used by pydrivers */
+		PyDict_Clear(bpy_pydriver_Dict);
 		Py_DECREF(bpy_pydriver_Dict);
 		bpy_pydriver_Dict = NULL;
 	}
@@ -1034,6 +1035,21 @@ static float pydriver_error(IpoDriver *driver) {
 	return 0.0f;
 }
 
+/* Update function, it gets rid of pydrivers global dictionary, forcing
+ * BPY_pydriver_eval to recreate it. This function is used to force
+ * reloading the Blender text module "pydrivers.py", if available, so
+ * updates in it reach pydriver evaluation. */
+void BPY_pydriver_update(void)
+{
+	if (bpy_pydriver_Dict) { /* free the global dict used by pydrivers */
+		PyDict_Clear(bpy_pydriver_Dict);
+		Py_DECREF(bpy_pydriver_Dict);
+		bpy_pydriver_Dict = NULL;
+	}
+
+	return;
+}
+
 /* for depsgraph.c, runs py expr once to collect all refs. made
  * to objects (self refs. to the object that owns the py driver
  * are not allowed). */

source/blender/src/drawipo.c

@@ -1759,7 +1759,10 @@ void do_ipobuts(unsigned short event)
 		if(ei) {
 			if(ei->icu->driver) {
 				if (ei->icu->driver->type == IPO_DRIVER_TYPE_PYTHON) {
-					/* eval user's expression once for validity */
+ 					/* first del pydriver's global dict, just in case
+					 * an available pydrivers.py module needs to be reloaded */
+					BPY_pydriver_update();
+					/* eval user's expression once for validity; update DAG */
 					BPY_pydriver_eval(ei->icu->driver);
 					DAG_scene_sort(G.scene);
 				}