Merge branch 'undo-experiments' into undo-experiments-idnames

Merge branch 'master' into undo-experiments

Cleanup .orig files from some merge...

Merge branch 'undo-experiments' into undo-experiments-idnames

Merge branch 'master' into undo-experiments

Merge branch 'undo-experiments' into undo-experiments-idnames

Merge branch 'master' into undo-experiments

Merge branch 'undo-experiments' into undo-experiments-idnames

undoexp: fix for missed func signature change.

Merge branch 'undo-experiments' into undo-experiments-idnames

Conflicts:
source/blender/blenkernel/BKE_blender_undo.h
source/blender/blenkernel/intern/blender_undo.c
source/blender/blenloader/intern/readfile.c
source/blender/editors/undo/memfile_undo.c

Merge branch 'master' into undo-experiments

undoexp: Fix major flaw in general logic of unchanged data detection.

Am not sure why it seemed to work that well so far... But using marker
saying that data did not change between n-2 and n-1 step when undoing
from n to n-1 is not really smart.

Fixed that by adding a 'is_identical_future' flag to memfile chunks,
which is set when storing the next undo step. And then using undo
direction to decide which flag to use to detect unchanged data.

This seesm to work to some extend, although for some reason very most
recent undo step seems to be evaluated when doing the first undo, not
sure why... Need to test that with actual working undo code in
undo-experiments-idnames branch anyway.

undoexp: more cleanup of debug printf.

Merge branch 'undo-experiments' into undo-experiments-idnames

undoexp: Silent/remove some debug prints.

Merge branch 'undo-experiments' into undo-experiments-idnames

Merge branch 'master' into undo-experiments

undoexp: refine handling of 'undo barrier'.

This also fixes the mesh keeping its edited shape when undoing out of
edit mode e.g.

undoexp: Tag renamed ID undo steps as 'full barrier'.

I.E. re-using data from old bmain is forbidden around an ID renaming.

This is a bit over-protective in most cases, since renaming an ID does
change its memfile data. So renamed ID should be reloaded from memfile
anyway.

But the problems might come (in some specific scenarii involving 'name
switching' between two IDs) from name-based lookup. Those could lead to
remapping some ID pointers in unchanged data-blocks to the wrong ID...

undoexp: Move old-data-management code to memfile undo callbacks.

Does not really make any sense to do that for any other kind of undo
currently, so better keep it in dedicated undotype callbacks.