Version: Blender 2.90.1 release

Fix T80899: Crash on editing multiple UVs of multiple different objects at the same time

The issue was two fold.

First something sets the loop element tag and doesn't clear it before
the UV code in question tries to use the tags. Added a sanity clear to
make sure that it operates on a clean tag state.

The next one was that the UV maps in question had quite a few points
that had zero length UV loop edges. This would lead to division by
zero.

Reviewed By: Jeroen Bakker, Brecht

Differential Revision: https://developer.blender.org/D8967

Fix T80771: Avoid changing the visibility of loose geometry when entering Sculpt Mode

When entering scultp mode the visibility from the Face Sets is copied to
the base mesh. This steps was considering that if a vertex belongs to a
face with a visibible Face Set ID, it should be visible. As loose
geometry may not have any faces, those vertex were set to hidden.

Now this function check if a vertex visibility should be modified by the
face sets (by checking the loops), avoiding modifying the visibility of
loose geometry unintentionally.

Reviewed By: sergey

Maniphest Tasks: T80771

Differential Revision: https://developer.blender.org/D8899

Fix T80520: Tris to Quads ignores UV delimit option

Fix T61985: NLA Bake exception baking pose with non-pose selection

Fix invert vertex group weight miscalculation for modifiers

Warp & weight vertex-group editing modifiers miscalculated vertex weight
inversion, the weights were multiplied before being subtracted from 1.

Ref D8241

Fix T78793, T79707: Cycles crash on macOS with older CPUs

Embree static libraries need additional linking flags to avoid SSE and
AVX symbols getting mixed up.

Cycles: Separate Embree device for each CPU Device.

Before, Cycles was using a shared Embree device across all instances.
This could result in crashes when viewport rendering and material
preview were using Cycles simultaneously.

Fixes issue T80042

Maniphest Tasks: T80042

Differential Revision: https://developer.blender.org/D8772

Fix T80437: Auto IK Double Generates IK constraints

Caused by rB9a7f5f1bb422.

If using Auto IK (or targetless IK and Auto IK together), two temporary
constraints were added.
- from pose_grab_with_ik_add (even for targetless IK)
- from add_pose_transdata (even for Auto IK)

Since both both do similar things, but cannot work in tandem (with
possibly different chainlengths for example), we have to decide which
type to prefer over the other (as in: do not create a constraint for the
other).
It seems better to ignore the 'Auto IK' option on bones that will
have targetless IK set up for them specificallly [e.g. defining special
chainlength]. This way you can still work with 'Auto IK' ON generally
[with interactive chainlength control], but also have specific bones that
need their own custom chainlength.

For now, the most straightforward fix is to
- only add constraints for Auto IK from pose_grab_with_ik_add()
- only add constraints for targetless IK from add_pose_transdata()

Note: this area has some potential for later refactoring:
- move creation of all temporary constraints to a single place
[preferably pose_grab_with_ik_add]
- use only those temporary constraints in transform code [atm. we still
flip CONSTRAINT_IK_AUTO around on the "original" -- unneccesarily, after
rB9a7f5f1bb422 a dedicated temporary constraint is now always available]
- clarify CONSTRAINT_IK_AUTO vs. CONSTRAINT_IK_TEMP
- obeying standard rotation locks on bones in the chain (not just the
the IK locks) is not consistent between targetless IK and Auto IK

Potential candidate for 2.90.1 as well as 2.83 LTS

Maniphest Tasks: T80437

Differential Revision: https://developer.blender.org/D8930

Fix T80885: Texture paint camera project crashes after undo/redo

Unmatched ED_image_undo_push_{begin/end},
add doc-strings noting why this is needed.

Thanks to @Baardaap for the initial fix.

Add versioning for 2.90 files that may have invalid mesh

rBf2d26409e83b fixed a serious problem with invalid mesh after an
operation with the extrude manifold.

Since BKE_mesh_validate_arrays is a slow operation, the chosen
interval between versions is relatively small and also only the
mentioned invalid mesh problem is tested.

Differential Revision: https://developer.blender.org/D8898

Fix OpenCL render error in large scenes

In scenes such as Cosmos Laundromat, there were memory allocations bigger than
2GB which would overflow.

Problem and solution found by AMD, thanks!

Fix T80630: potential crash in volume grids in Eevee shaders

Found by address sanitizer.

Fix T80728: UV edge select splits UV's for lasso/box/circle select

Oversight in 411c5238a2fef ignored sticky selection.

Use 'uvedit_edge_select_set_with_sticky' to make sure
sticky options are respected.

Also skip checking the existing selection since that only checks the
current UV, not all connected UV's which is needed for sticky selection.

The extra checks to avoid updating UV's isn't such an advantage as
only meshed in the selected region are tagged for updating.

Fix T78392: [2.83.5, 2.90, 2.91] Crash on undo/ redo after changing modes.

During undo/redo read code is expected to clear the `OB_MODE_EDIT`
bitflag of `Object.mode`, for some reasons.

This was not done anymore for re-used Objects, we need to add a special
handling case for that too.

Should be backported to 2.90 and 2.83 (will probably not be straight
forward for the latter).

Fix T80457: Library Override - Custom Property to Drive Child Particles results in Crash.

RNA diffing code was not dealing properly valid NULL PointerRNA (like
the empty texture slots of a ParticleSettings e.g., which were cause of
crash in that report).

To be backported to 2.90 and 2.83.

Fix T80694: Crash reloading scripts from the Python console

Running `bpy.ops.script.reload()` from Python was crashing
since the operator being called was it's self freed.

Change the reload operator to defer execution - as supporting
re-registration during execution is quite involved for a corner-case.

Fix T80589: Translations in python scripts are missing.

Python 3.8 changed handling of constant values in its AST tool.
This code should work on both officialy supported 3.7, and newer 3.8,
for now.

Fix T62504: Crash accessing depsgraph from evaluated view layer

Use correct owner_id types for depsgraph view_layer properties
instead of inheriting from the Depsgraph which is set to NULL.

Fix T77584: Edit Mode crash with shape keys created on blank mesh

Entering edit-mode after creating shape keys on a blank mesh would crash.

Regression in 9b9f84b317fef which prevented initializing empty
shape keys when there is no shape key offset data available.