This commit enables Blender 4.5 to use (to some extent) blendfiles from
Blender 5.0 and later using 'long' ID names (i.e. ID names over 63 bytes).
On a more general perspective, it also introduces safer handling of
potentially corrupted ID names in a blendfile.
This is achieved by carefully checking for non-null terminated ID names
early on in readfile process, and then:
* Truncating and ensuring uniqueness of ID names.
* Doing similar process for action slot and slot users identifiers.
* In linking (and appending) context, such IDs are totally ignored. They are
not listed, and are considered as missing if some other (valid) linked ID
attempt to indirectly link them).
* Informing users through usual reporting ways.
Technically, this mainly changes two areas of the readfile code related to IDs
themselves:
* The utils `blo_bhead_id_name` that returns the ID name of an ID BHead,
without actually reading that ID, now check for a valid null-terminated
string of `MAX_ID_NAME` max size, and returns a `nullptr` on error.
_This essentially prevents listing and linking such IDs, in any way._
* The actual ID reading code (`read_id_struct`) does the same check, and
truncate the ID name to its maximum allowed length.
* Both of above checks also set a new FileData flag
(`FD_FLAGS_HAS_LONG_ID_NAME`), which is used to ensure that ID names (and
related actions slots identifiers) remain unique, and report to info to the
user.
Implements #137608.
Branched out from !137196.
Co-authored-by: michal.krupa <michal.krupa@cdprojektred.com>
Co-authored-by: Campbell Barton <ideasman42@gmail.com>
Pull Request: https://projects.blender.org/blender/blender/pulls/139336
a883f555ae