Fix T62706: Orphan Data : I have now to save a file, close and reopen it, only then I can purge previous deleted meshes.

libquery code has some specific handling for IDs tagged as 'no_main',
among which to never consider them as refcounted/refcounting other IDs.

This is fine, but it also means we have to be careful when moving an ID
from main to out-of-main status, to do all id remapping we need
//before// we tag it as no_main.

That was a bit tedious to track down, we'll have to be careful that all
the corner cases we have to take care of, do not end up in a giant soup
of expections to exceptions, where nobody can find its way anymore...

1 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/library_remap.c b/source/blender/blenkernel/intern/library_remap.c
index 04ccdc729da..d4e30bc07e9 100644
--- a/source/blender/blenkernel/intern/library_remap.c
+++ b/source/blender/blenkernel/intern/library_remap.c
@@ -1001,7 +1001,9 @@ static void id_delete(Main *bmain, const bool do_tagged_deletion)
 					if ((id->tag & tag) || (id->lib != NULL && (id->lib->id.tag & tag))) {
 						BLI_remlink(lb, id);
 						BLI_addtail(&tagged_deleted_ids, id);
-						id->tag |= tag | LIB_TAG_NO_MAIN;
+						/* Do not tag as no_main now, we want to unlink it first (lower-level ID management code
+						 * has some specific handling of 'nom main' IDs that would be a problem in that case). */
+						id->tag |= tag;
 						keep_looping = true;
 					}
 				}
@@ -1021,6 +1023,8 @@ static void id_delete(Main *bmain, const bool do_tagged_deletion)
 				            ID_REMAP_FLAG_NEVER_NULL_USAGE | ID_REMAP_FORCE_NEVER_NULL_USAGE);
 				/* Since we removed ID from Main, we also need to unlink its own other IDs usages ourself. */
 				BKE_libblock_relink_ex(bmain, id, NULL, NULL, true);
+				/* Now we can safely mark that ID as not being in Main database anymore. */
+				id->tag |= LIB_TAG_NO_MAIN;
 				/* This is needed because we may not have remapped usages of that ID by other deleted ones. */
 //				id->us = 0;  /* Is it actually? */
 			}