Fix #30231: Drag and Droping Parenting from Outliner giving unnecessary Loop Error

In fact, error was much deeper and DND parenting in outliner used to parent all selected
objects to drop target, not just currently dragging object.

This was caused by code sharing between Parent Set operator and this DND operator which
was iterating all selected objects in scene and was setting parent to it.

Solved issue by separating actual parenting code which makes specified object be parented
to specified parent and moved iterating to Parent Set exec callback.

Now both of discovered issues (unneeded loop error and parenting all selected objects)
are solved, but more extensive testing of this changes are welcome.

3 files changed, 132 insertions, 111 deletions

diff --git a/source/blender/editors/include/ED_object.h b/source/blender/editors/include/ED_object.h
index 3e78a5649e5..85e68ba7ab4 100644
--- a/source/blender/editors/include/ED_object.h
+++ b/source/blender/editors/include/ED_object.h
@@ -84,7 +84,7 @@ typedef enum eParentType {
 extern struct EnumPropertyItem prop_clear_parent_types[];
 extern struct EnumPropertyItem prop_make_parent_types[];
 
-int ED_object_parent_set(struct bContext *C, struct wmOperator *op, struct Object *par, int partype);
+int ED_object_parent_set(struct ReportList *reports, struct Main *bmain, struct Scene *scene, struct Object *ob, struct Object *par, int partype);
 void ED_object_parent_clear(struct bContext *C, int type);
 
 
diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index 1a226112db4..c1c85eb2a10 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -519,10 +519,8 @@ EnumPropertyItem prop_make_parent_types[] = {
 	{0, NULL, 0, NULL, NULL}
 };
 
-int ED_object_parent_set(bContext *C, wmOperator *op, Object *par, int partype)
+int ED_object_parent_set(ReportList *reports, Main *bmain, Scene *scene, Object *ob, Object *par, int partype)
 {
-	Main *bmain= CTX_data_main(C);
-	Scene *scene= CTX_data_scene(C);
 	bPoseChannel *pchan= NULL;
 	int pararm= ELEM4(partype, PAR_ARMATURE, PAR_ARMATURE_NAME, PAR_ARMATURE_ENVELOPE, PAR_ARMATURE_AUTO);
 	
@@ -561,136 +559,144 @@ int ED_object_parent_set(bContext *C, wmOperator *op, Object *par, int partype)
 		pchan= get_active_posechannel(par);
 		
 		if(pchan==NULL) {
-			BKE_report(op->reports, RPT_ERROR, "No active Bone");
+			BKE_report(reports, RPT_ERROR, "No active Bone");
 			return 0;
 		}
 	}
 	
-	/* context iterator */
-	CTX_DATA_BEGIN(C, Object*, ob, selected_editable_objects) 
-	{
-		if (ob!=par) {
-			if (BKE_object_parent_loop_check(par, ob)) {
-				BKE_report(op->reports, RPT_ERROR, "Loop in parents");
+	if (ob!=par) {
+		if (BKE_object_parent_loop_check(par, ob)) {
+			BKE_report(reports, RPT_ERROR, "Loop in parents");
+			return 0;
+		}
+		else {
+			Object workob;
+			
+			/* apply transformation of previous parenting */
+			/* object_apply_mat4(ob, ob->obmat); */ /* removed because of bug [#23577] */
+			
+			/* set the parent (except for follow-path constraint option) */
+			if (partype != PAR_PATH_CONST) {
+				ob->parent= par;
 			}
-			else {
-				Object workob;
-				
-				/* apply transformation of previous parenting */
-				/* object_apply_mat4(ob, ob->obmat); */ /* removed because of bug [#23577] */
+			
+			/* handle types */
+			if (pchan)
+				BLI_strncpy(ob->parsubstr, pchan->name, sizeof(ob->parsubstr));
+			else
+				ob->parsubstr[0]= 0;
 				
-				/* set the parent (except for follow-path constraint option) */
-				if (partype != PAR_PATH_CONST) {
-					ob->parent= par;
-				}
+			if (partype == PAR_PATH_CONST) {
+				/* don't do anything here, since this is not technically "parenting" */
+			}
+			else if (ELEM(partype, PAR_CURVE, PAR_LATTICE) || (pararm))
+			{
+				/* partype is now set to PAROBJECT so that invisible 'virtual' modifiers don't need to be created
+				 * NOTE: the old (2.4x) method was to set ob->partype = PARSKEL, creating the virtual modifiers
+				 */
+				ob->partype= PAROBJECT;	/* note, dna define, not operator property */
+				//ob->partype= PARSKEL; /* note, dna define, not operator property */
 				
-				/* handle types */
-				if (pchan)
-					BLI_strncpy(ob->parsubstr, pchan->name, sizeof(ob->parsubstr));
-				else
-					ob->parsubstr[0]= 0;
-					
-				if (partype == PAR_PATH_CONST) {
-					/* don't do anything here, since this is not technically "parenting" */
-				}
-				else if (ELEM(partype, PAR_CURVE, PAR_LATTICE) || (pararm))
+				/* BUT, to keep the deforms, we need a modifier, and then we need to set the object that it uses */
+				// XXX currently this should only happen for meshes, curves, surfaces, and lattices - this stuff isn't available for metas yet
+				if (ELEM5(ob->type, OB_MESH, OB_CURVE, OB_SURF, OB_FONT, OB_LATTICE))
 				{
-					/* partype is now set to PAROBJECT so that invisible 'virtual' modifiers don't need to be created
-					 * NOTE: the old (2.4x) method was to set ob->partype = PARSKEL, creating the virtual modifiers
-					 */
-					ob->partype= PAROBJECT;	/* note, dna define, not operator property */
-					//ob->partype= PARSKEL; /* note, dna define, not operator property */
+					ModifierData *md;
 					
-					/* BUT, to keep the deforms, we need a modifier, and then we need to set the object that it uses */
-					// XXX currently this should only happen for meshes, curves, surfaces, and lattices - this stuff isn't available for metas yet
-					if (ELEM5(ob->type, OB_MESH, OB_CURVE, OB_SURF, OB_FONT, OB_LATTICE))
-					{
-						ModifierData *md;
-						
-						switch (partype) {
-						case PAR_CURVE: /* curve deform */
-							md= ED_object_modifier_add(op->reports, bmain, scene, ob, NULL, eModifierType_Curve);
-							((CurveModifierData *)md)->object= par;
-							break;
-						case PAR_LATTICE: /* lattice deform */
-							md= ED_object_modifier_add(op->reports, bmain, scene, ob, NULL, eModifierType_Lattice);
-							((LatticeModifierData *)md)->object= par;
-							break;
-						default: /* armature deform */
-							md= ED_object_modifier_add(op->reports, bmain, scene, ob, NULL, eModifierType_Armature);
-							((ArmatureModifierData *)md)->object= par;
-							break;
-						}
+					switch (partype) {
+					case PAR_CURVE: /* curve deform */
+						md= ED_object_modifier_add(reports, bmain, scene, ob, NULL, eModifierType_Curve);
+						((CurveModifierData *)md)->object= par;
+						break;
+					case PAR_LATTICE: /* lattice deform */
+						md= ED_object_modifier_add(reports, bmain, scene, ob, NULL, eModifierType_Lattice);
+						((LatticeModifierData *)md)->object= par;
+						break;
+					default: /* armature deform */
+						md= ED_object_modifier_add(reports, bmain, scene, ob, NULL, eModifierType_Armature);
+						((ArmatureModifierData *)md)->object= par;
+						break;
 					}
 				}
-				else if (partype == PAR_BONE)
-					ob->partype= PARBONE; /* note, dna define, not operator property */
-				else
-					ob->partype= PAROBJECT;	/* note, dna define, not operator property */
+			}
+			else if (partype == PAR_BONE)
+				ob->partype= PARBONE; /* note, dna define, not operator property */
+			else
+				ob->partype= PAROBJECT;	/* note, dna define, not operator property */
+			
+			/* constraint */
+			if(partype == PAR_PATH_CONST) {
+				bConstraint *con;
+				bFollowPathConstraint *data;
+				float cmat[4][4], vec[3];
 				
-				/* constraint */
-				if(partype == PAR_PATH_CONST) {
-					bConstraint *con;
-					bFollowPathConstraint *data;
-					float cmat[4][4], vec[3];
-					
-					con = add_ob_constraint(ob, "AutoPath", CONSTRAINT_TYPE_FOLLOWPATH);
-					
-					data = con->data;
-					data->tar = par;
-					
-					get_constraint_target_matrix(scene, con, 0, CONSTRAINT_OBTYPE_OBJECT, NULL, cmat, scene->r.cfra);
-					sub_v3_v3v3(vec, ob->obmat[3], cmat[3]);
-					
-					ob->loc[0] = vec[0];
-					ob->loc[1] = vec[1];
-					ob->loc[2] = vec[2];
-				}
-				else if(pararm && ob->type==OB_MESH && par->type == OB_ARMATURE) {
-					if(partype == PAR_ARMATURE_NAME)
-						create_vgroups_from_armature(op->reports, scene, ob, par, ARM_GROUPS_NAME, 0);
-					else if(partype == PAR_ARMATURE_ENVELOPE)
-						create_vgroups_from_armature(op->reports, scene, ob, par, ARM_GROUPS_ENVELOPE, 0);
-					else if(partype == PAR_ARMATURE_AUTO) {
-						WM_cursor_wait(1);
-						create_vgroups_from_armature(op->reports, scene, ob, par, ARM_GROUPS_AUTO, 0);
-						WM_cursor_wait(0);
-					}
-					/* get corrected inverse */
-					ob->partype= PAROBJECT;
-					what_does_parent(scene, ob, &workob);
-					
-					invert_m4_m4(ob->parentinv, workob.obmat);
-				}
-				else {
-					/* calculate inverse parent matrix */
-					what_does_parent(scene, ob, &workob);
-					invert_m4_m4(ob->parentinv, workob.obmat);
+				con = add_ob_constraint(ob, "AutoPath", CONSTRAINT_TYPE_FOLLOWPATH);
+				
+				data = con->data;
+				data->tar = par;
+				
+				get_constraint_target_matrix(scene, con, 0, CONSTRAINT_OBTYPE_OBJECT, NULL, cmat, scene->r.cfra);
+				sub_v3_v3v3(vec, ob->obmat[3], cmat[3]);
+				
+				ob->loc[0] = vec[0];
+				ob->loc[1] = vec[1];
+				ob->loc[2] = vec[2];
+			}
+			else if(pararm && ob->type==OB_MESH && par->type == OB_ARMATURE) {
+				if(partype == PAR_ARMATURE_NAME)
+					create_vgroups_from_armature(reports, scene, ob, par, ARM_GROUPS_NAME, 0);
+				else if(partype == PAR_ARMATURE_ENVELOPE)
+					create_vgroups_from_armature(reports, scene, ob, par, ARM_GROUPS_ENVELOPE, 0);
+				else if(partype == PAR_ARMATURE_AUTO) {
+					WM_cursor_wait(1);
+					create_vgroups_from_armature(reports, scene, ob, par, ARM_GROUPS_AUTO, 0);
+					WM_cursor_wait(0);
 				}
+				/* get corrected inverse */
+				ob->partype= PAROBJECT;
+				what_does_parent(scene, ob, &workob);
 				
-				ob->recalc |= OB_RECALC_OB|OB_RECALC_DATA;
+				invert_m4_m4(ob->parentinv, workob.obmat);
+			}
+			else {
+				/* calculate inverse parent matrix */
+				what_does_parent(scene, ob, &workob);
+				invert_m4_m4(ob->parentinv, workob.obmat);
 			}
+			
+			ob->recalc |= OB_RECALC_OB|OB_RECALC_DATA;
 		}
 	}
-	CTX_DATA_END;
-
-	DAG_scene_sort(bmain, scene);
-	DAG_ids_flush_update(bmain, 0);
-	WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
-	WM_event_add_notifier(C, NC_OBJECT|ND_PARENT, NULL);
 
 	return 1;
 }
 
 static int parent_set_exec(bContext *C, wmOperator *op)
 {
+	Main *bmain= CTX_data_main(C);
+	Scene *scene= CTX_data_scene(C);
 	Object *par= ED_object_active_context(C);
 	int partype= RNA_enum_get(op->ptr, "type");
+	int ok = 1;
 
-	if(ED_object_parent_set(C, op, par, partype))
-		return OPERATOR_FINISHED;
-	else
+	CTX_DATA_BEGIN(C, Object*, ob, selected_editable_objects)
+	{
+		if (!ED_object_parent_set(op->reports, bmain, scene, ob, par, partype)) {
+			ok = 0;
+			break;
+		}
+	}
+	CTX_DATA_END;
+
+	if (!ok)
 		return OPERATOR_CANCELLED;
+
+	DAG_scene_sort(bmain, scene);
+	DAG_ids_flush_update(bmain, 0);
+	WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
+	WM_event_add_notifier(C, NC_OBJECT|ND_PARENT, NULL);
+
+	return OPERATOR_FINISHED;
 }
 
 
diff --git a/source/blender/editors/space_outliner/outliner_edit.c b/source/blender/editors/space_outliner/outliner_edit.c
index 80bd8291757..32c5683607d 100644
--- a/source/blender/editors/space_outliner/outliner_edit.c
+++ b/source/blender/editors/space_outliner/outliner_edit.c
@@ -1433,15 +1433,24 @@ void OUTLINER_OT_keyingset_remove_selected(wmOperatorType *ot)
 
 static int parent_drop_exec(bContext *C, wmOperator *op)
 {
-	Object *par = NULL;
+	Object *par = NULL, *ob = NULL;
+	Main *bmain= CTX_data_main(C);
+	Scene *scene= CTX_data_scene(C);
 	int partype = -1;
-	char parname[32];
+	char parname[MAX_ID_NAME], childname[MAX_ID_NAME];
 
 	partype= RNA_enum_get(op->ptr, "type");
 	RNA_string_get(op->ptr, "parent", parname);
 	par= (Object *)find_id("OB", parname);
+	RNA_string_get(op->ptr, "child", childname);
+	ob= (Object *)find_id("OB", childname);
+
+	ED_object_parent_set(op->reports, bmain, scene, ob, par, partype);
 
-	ED_object_parent_set(C, op, par, partype);
+	DAG_scene_sort(bmain, scene);
+	DAG_ids_flush_update(bmain, 0);
+	WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
+	WM_event_add_notifier(C, NC_OBJECT|ND_PARENT, NULL);
 
 	return OPERATOR_FINISHED;
 }
@@ -1482,6 +1491,7 @@ static int parent_drop_invoke(bContext *C, wmOperator *op, wmEvent *event)
 	Object *ob= NULL;
 	SpaceOops *soops= CTX_wm_space_outliner(C);
 	ARegion *ar= CTX_wm_region(C);
+	Main *bmain= CTX_data_main(C);
 	Scene *scene= CTX_data_scene(C);
 	TreeElement *te= NULL;
 	TreeElement *te_found= NULL;
@@ -1519,7 +1529,12 @@ static int parent_drop_invoke(bContext *C, wmOperator *op, wmEvent *event)
 			ED_base_object_select(object_in_scene(ob, scene), BA_SELECT);
 		
 		if ((par->type != OB_ARMATURE) && (par->type != OB_CURVE) && (par->type != OB_LATTICE)) {
-			ED_object_parent_set(C, op, par, partype);
+			if (ED_object_parent_set(op->reports, bmain, scene, ob, par, partype)) {
+				DAG_scene_sort(bmain, scene);
+				DAG_ids_flush_update(bmain, 0);
+				WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
+				WM_event_add_notifier(C, NC_OBJECT|ND_PARENT, NULL);
+			}
 		}
 		else {
 			/* Menu creation */