Fix None output node bug in JITLinker.create_jitable_thunk

[ricardoV94]

• Also fixes bug in JITCompiler when first output of inner fgraph is an input variable, as can happen in some specific functions with updates

Closes #1195

[codecov]

Codecov Report

Merging #1205 (0a34abd) into main (5d97ffa) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1205   +/-   ##
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  Coverage   79.14%   79.14%           
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  Files         173      173           
  Lines       48485    48486    +1     
  Branches    10966    10966           
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+ Hits        38375    38376    +1     
  Misses       7607     7607           
  Partials     2503     2503           

Impacted Files	Coverage Δ
aesara/link/utils.py	61.12% <ø> (ø)
aesara/link/basic.py	86.49% <100.00%> (ø)
aesara/sandbox/rng_mrg.py	84.14% <100.00%> (+0.03%)	⬆️

[ricardoV94]

This wasn't changed by this PR, but I wonder does the hack actually work? There's a whole bunch of logic downstream concerning garbage collection and whatnot that is supposed to rely on this. Too dense for me to take a look though :D

[brandonwillard]

This wasn't changed by this PR, but I wonder does the hack actually work? There's a whole bunch of logic downstream concerning garbage collection and whatnot that is supposed to rely on this. Too dense for me to take a look though :D

It must be working; how else have we been using Numba/JAX to evaluate graphs?

The hackish part is that we were and still are (to some extent) using the old Function/VM framework to do something that it wasn't designed to do. For example, we don't have a thunk for each node in the graph, like we normally would.

To be clear, shared variable and updates support for the JIT backends has always been incomplete, and this falls squarely into the latter.