* Added description string to operator types, should be set along with ot->idname when defining ops.

* User interface uses this as a tooltip when NULL or "" is given.
* Python doc generation includes this description 
* Python defined ops take the description as an argument.

* NULL check to image_ops.c, was crashing on exit when there was an image open.

source/blender/editors/interface/interface.c

@@ -2308,6 +2308,10 @@ uiBut *ui_def_but_operator(uiBlock *block, int type, char *opname, int opcontext
 		if(ot) str= ot->name;
 		else str= opname;
 	}
+	
+	if ((!tip || tip[0]=='\0') && ot->description) {
+		tip= ot->description;
+	}
 
 	but= ui_def_but(block, type, -1, str, x1, y1, x2, y2, NULL, 0, 0, 0, 0, tip);
 	but->opname= opname;

source/blender/editors/space_image/image_ops.c

@@ -1221,6 +1221,9 @@ static void sample_draw(const bContext *C, ARegion *ar, void *arg_info)
 	ImBuf *ibuf= ED_space_image_buffer(sima);
 	ImageSampleInfo *info= arg_info;
 
+	if(ibuf == NULL)
+		return;
+	
 	draw_image_info(ar, ibuf->channels, info->x, info->y, info->colp,
 		info->colfp, info->zp, info->zfp);
 }

source/blender/editors/space_sequencer/sequencer_add.c

@@ -213,6 +213,7 @@ void SEQUENCER_OT_add_scene_strip(struct wmOperatorType *ot)
 	/* identifiers */
 	ot->name= "Add Scene Strip";
 	ot->idname= "SEQUENCER_OT_add_scene_strip";
+	ot->description= "Add a strip to the sequencer using a blender scene as a source";
 
 	/* api callbacks */
 	ot->invoke= sequencer_add_scene_strip_invoke;
@@ -300,6 +301,7 @@ void SEQUENCER_OT_add_movie_strip(struct wmOperatorType *ot)
 	/* identifiers */
 	ot->name= "Add Movie Strip";
 	ot->idname= "SEQUENCER_OT_add_movie_strip";
+	ot->description= "Add a movie strip to the sequencer";
 
 	/* api callbacks */
 	ot->invoke= sequencer_add_movie_strip_invoke;
@@ -400,6 +402,7 @@ void SEQUENCER_OT_add_sound_strip(struct wmOperatorType *ot)
 	/* identifiers */
 	ot->name= "Add Sound Strip";
 	ot->idname= "SEQUENCER_OT_add_sound_strip";
+	ot->description= "Add a sound strip to the sequencer";
 
 	/* api callbacks */
 	ot->invoke= sequencer_add_sound_strip_invoke;
@@ -492,6 +495,7 @@ void SEQUENCER_OT_add_image_strip(struct wmOperatorType *ot)
 	/* identifiers */
 	ot->name= "Add Image Strip";
 	ot->idname= "SEQUENCER_OT_add_image_strip";
+	ot->description= "Add an image or image sequence to the sequencer";
 
 	/* api callbacks */
 	ot->invoke= sequencer_add_image_strip_invoke;
@@ -623,6 +627,7 @@ void SEQUENCER_OT_add_effect_strip(struct wmOperatorType *ot)
 	/* identifiers */
 	ot->name= "Add Effect Strip";
 	ot->idname= "SEQUENCER_OT_add_effect_strip";
+	ot->description= "Add an effect to the sequencer, most are applied ontop of existing strips";
 
 	/* api callbacks */
 	ot->invoke= sequencer_add_effect_strip_invoke;

source/blender/makesdna/DNA_windowmanager_types.h

@@ -123,7 +123,8 @@ typedef struct wmOperatorType {
 	struct wmOperatorType *next, *prev;
 	
 	char *name;		/* text for ui, undo */
-	char *idname;	/* unique identifier */
+	char *idname;		/* unique identifier */
+	char *description;	/* tooltips and python docs */
 	
 	/* this callback executes the operator without any interactive input,
 	 * parameters may be provided through operator properties. cannot use

source/blender/python/epy_doc_gen.py

@@ -265,6 +265,7 @@ def op2epy(target_path):
 		
 		out.write('def %s(%s):\n' % (op, ', '.join(kw_args)))
 		out.write('\t"""\n')
+		out.write('\t%s\n' % rna_struct.description)
 		for desc in kw_arg_attrs:
 			out.write('\t%s\n' % desc)
 		out.write('\t@rtype: None\n')

source/blender/python/intern/bpy_opwrapper.c

@@ -44,6 +44,7 @@ typedef struct PyOperatorType {
 	void *next, *prev;
 	char idname[OP_MAX_TYPENAME];
 	char name[OP_MAX_TYPENAME];
+	char description[OP_MAX_TYPENAME]; // XXX should be longer?
 	PyObject *py_invoke;
 	PyObject *py_exec;
 } PyOperatorType;
@@ -276,6 +277,7 @@ void PYTHON_OT_wrapper(wmOperatorType *ot, void *userdata)
 	/* identifiers */
 	ot->name= pyot->name;
 	ot->idname= pyot->idname;
+	ot->description= pyot->description;
 
 	/* api callbacks */
 	if (pyot->py_invoke != Py_None)
@@ -342,10 +344,11 @@ PyObject *PYOP_wrap_add(PyObject *self, PyObject *args)
 
 	char *idname= NULL;
 	char *name= NULL;
+	char *description= NULL;
 	PyObject *invoke= NULL;
 	PyObject *exec= NULL;
 
-	if (!PyArg_ParseTuple(args, "ssOO", &idname, &name, &invoke, &exec)) {
+	if (!PyArg_ParseTuple(args, "sssOO", &idname, &name, &description, &invoke, &exec)) {
 		PyErr_SetString( PyExc_AttributeError, "expected 2 strings and 2 function objects");
 		return NULL;
 	}
@@ -362,8 +365,9 @@ PyObject *PYOP_wrap_add(PyObject *self, PyObject *args)
 
 	pyot= MEM_callocN(sizeof(PyOperatorType), "PyOperatorType");
 
-	strcpy(pyot->idname, idname);
-	strcpy(pyot->name, name);
+	strncpy(pyot->idname, idname, sizeof(pyot->idname));
+	strncpy(pyot->name, name, sizeof(pyot->name));
+	strncpy(pyot->description, description, sizeof(pyot->description));
 	pyot->py_invoke= invoke;
 	pyot->py_exec= exec;
 	Py_INCREF(invoke);

source/blender/windowmanager/intern/wm_operators.c

@@ -101,7 +101,7 @@ void WM_operatortype_append(void (*opfunc)(wmOperatorType*))
 	ot= MEM_callocN(sizeof(wmOperatorType), "operatortype");
 	ot->srna= RNA_def_struct(&BLENDER_RNA, "", "OperatorProperties");
 	opfunc(ot);
-	RNA_def_struct_ui_text(ot->srna, ot->name, "DOC_BROKEN"); /* TODO - add a discription to wmOperatorType? */
+	RNA_def_struct_ui_text(ot->srna, ot->name, ot->description ? ot->description:""); // XXX All ops should have a description but for now allow them not to.
 	RNA_def_struct_identifier(ot->srna, ot->idname);
 	BLI_addtail(&global_ops, ot);
 }