fix(model): support session: null option for save() to opt out of automatic session option with transactionAsyncLocalStorage

[vkarpov15]

Fix #14736

Summary

doc.save({ session: null }) should override default session option from transactionAsyncLocalStorage. That's how await TestModel.find().setOptions({ session: null }) and others work, it looks like save() is the only one affected

Examples

[hasezoey]

LGTM, should this also be added to #14742 before it is merged?

[hasezoey]

Actually now looking at the Replica set tests, they are consistently failing with this PR:

test output snippit for reference

  5 failing
  1) transactions
       basic example:
      AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
  assert.ok(!doc)

      + expected - actual
      -false
      +true
      
      at /home/runner/work/mongoose/mongoose/test/docs/transactions.test.js:62:26
      at runMicrotasks (<anonymous>)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)

  2) transactions
       abort:
      AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
2 !== 0

      + expected - actual
      -2
      +0
      
      at /home/runner/work/mongoose/mongoose/test/docs/transactions.test.js:110:28
      at runMicrotasks (<anonymous>)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)

  3) transactions
       transaction() resets $isNew on error:
      AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
  assert.ok(!exists)

      + expected - actual
      -false
      +true
      
      at Context.<anonymous> (test/docs/transactions.test.js:432:12)
      at runMicrotasks (<anonymous>)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)

  4) transactions
       transaction() resets $isNew between retries (gh-13698):
     MongoServerError: E11000 duplicate key error collection: mongoose_test.Test index: _id_ dup key: { _id: ObjectId('669029c2fa5898976ba20094') }
      at InsertOneOperation.execute (node_modules/mongodb/lib/operations/insert.js:51:19)
      at runMicrotasks (<anonymous>)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)
      at async executeOperation (node_modules/mongodb/lib/operations/execute_operation.js:136:16)
      at async Collection.insertOne (node_modules/mongodb/lib/collection.js:155:16)

  5) transactions
       populate (gh-6754)
         `Document#populate()` supports overwriting the session:
      AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
  assert.ok(!article.author)

      + expected - actual
      -false
      +true
      
      at /home/runner/work/mongoose/mongoose/test/docs/transactions.test.js:287:32
      at runMicrotasks (<anonymous>)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)

---

EDIT:
after some quick investigation, could it be that options.session is just never transferred to saveOptions.session? though i dont understand how it worked before then.

[vkarpov15]

@hasezoey the save() function creates saveOptions based on options here:

mongoose/lib/model.js

Lines 558 to 560 in 70e8e19

	if (options.hasOwnProperty('session')) {
	this.$session(options.session);
	}