Differential D14191
Fix T95997: Crash when entering edit mode Authored by Sergey Sharybin (sergey) on Feb 24 2022, 2:18 PM. Tags None Subscribers None
Details The issue was uncovered by the 0f89bcdbebf5, but the root cause goes Bring code closer to the older state where such modification is only From own tests works seems to work fine, but extra eyes and testing
Diff Detail
Event TimelineComment Actions I'm having trouble understanding what this fix does exactly. As I understand it, modifying the input mesh is a problem because multiple objects might be referencing the same mesh/editmesh. There are no mutex locks so this is not thread safe. Now it is only modifying the input mesh for objects in edit mode, and not objects sharing the same mesh/editmesh which are not in edit mode. However what about multiple objects in edit mode at the same time, that share the same mesh/editmesh? Comment Actions I think it is only one object which will have ob->mode & OB_MODE_EDIT) even when you select multiple objects and go into edit mode. This is the check in object_update.c which was done before my changes in the rB0f89bcdbebf5. Comment Actions I see multiple objects sharing a mesh while being in edit mode is not supported indeed, as per comments in ED_object_editmode_enter_ex. It would be good to have a comment here explaining this, like: /* Modifying the input mesh is weak, however as there can only be one object in edit mode * even if multiple are sharing the same mesh this should be thread safe. */ Seems to work ok in my tests. Comment Actions Thanks Brecht for doublechecking and verifying finding about multriple objects sharing the same mesh in edit mode! Indeed is a good idea to aff a comment about it. This is what this update is about: add comment. |