Fix T37709: Memory corruption when freeing custom bone shape objects

Summary:
Issue was caused by access to pchan->custom object from channel free
function when freeing all objects from main. Order of objects free
is not defined and such an access might easily end up with access
to freed memory.

We don't need to do user counter stuff when freeing main, so added
an _ex functions with do_id_user flag which is used when freeing main.

We had the same issue with other datablocks, so now it should be
easier to support relevant user counter.

This issue was caused by the fix for T36391, so perhaps that's indeed
high time to do real user counter.

Reviewers: brecht, campbellbarton

Reviewed By: campbellbarton

Maniphest Tasks: T37709

Differential Revision: https://developer.blender.org/D137

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_action.h b/source/blender/blenkernel/BKE_action.h
index 3ac5c8c9a76..9068be970b5 100644
--- a/source/blender/blenkernel/BKE_action.h
+++ b/source/blender/blenkernel/BKE_action.h
@@ -134,13 +134,16 @@ void action_groups_clear_tempflags(struct bAction *act);
 /* Pose API ----------------- */	
 
 void                 BKE_pose_channel_free(struct bPoseChannel *pchan);
+void                 BKE_pose_channel_free_ex(struct bPoseChannel *pchan, bool do_id_user);
 
 void                 BKE_pose_channels_free(struct bPose *pose);
+void                 BKE_pose_channels_free_ex(struct bPose *pose, bool do_id_user);
 
 void                 BKE_pose_channels_hash_make(struct bPose *pose);
 void                 BKE_pose_channels_hash_free(struct bPose *pose);
 
 void                 BKE_pose_free(struct bPose *pose);
+void                 BKE_pose_free_ex(struct bPose *pose, bool do_id_user);
 void                 BKE_pose_copy_data(struct bPose **dst, struct bPose *src, const bool copy_constraints);
 void                 BKE_pose_channel_copy_data(struct bPoseChannel *pchan, const struct bPoseChannel *pchan_from);
 struct bPoseChannel *BKE_pose_channel_find_name(const struct bPose *pose, const char *name);