Missing lazy context for intermediate association (has_one ... through)

[id-ilych]

Hello Dmitry 👋

I noticed an unexpected behavior in a context of has_one ... through associations.
Imagine a model:

class Alice < ApplicationRecord
  has_one :bob
  has_one :charlie, through: :bob
end

and then

record = Alice.preload_associations_lazily.find(some_id)
assert record.lazy_preload_context.present?, "lazy context is missing for alice"

# at this point record has no associations loaded
record.charlie
# at this point record has both bob and charlie associations loaded

assert record.charlie.lazy_preload_context.present?, "lazy context is missing for charlie"
assert record.bob.lazy_preload_context.present?, "lazy context is missing for bob"

Observed behavior: the last assertion fails
Expected behavior: all assertions succeed

Steps to reproduce:

1. Clone https://github.com/id-ilych/ar_lazy_preload_bug
2. docker compose up -d && bin/setup && bin/rails test

Output:

% bin/rails test
Running 1 tests in a single process (parallelization threshold is 50)
Run options: --seed 56792

# Running:

F

Failure:
AliceTest#test_the_truth [test/models/alice_test.rb:15]:
lazy context is missing for bob


rails test test/models/alice_test.rb:4



Finished in 0.127767s, 7.8267 runs/s, 46.9605 assertions/s.
1 runs, 6 assertions, 1 failures, 0 errors, 0 skips