PostgreSQL: transaction() doesn't guarantee use of a database transaction

[alxndrsn]

Node version: 14.15.0
Sails version (sails): 1.4.0
ORM hook version (sails-hook-orm): 2.1.1
DB adapter & version (e.g. [email protected]): [email protected]

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Observed

Calling datastore.transaction(during) when using the sails-postgresql adapter for Waterline doesn't guarantee that during will be run inside a database transaction.

If there is no transaction-specific code in the executed SQL, the during code will complete without error, so the user may not be aware that their query or queries were not transactional.

Steps to recreate

Example project: https://github.com/alxndrsn/sailsjs-postgres-transactions-maybe

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Maybe related to #7017.

[sailsbot]

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[alxndrsn]

I've opened a PR to fix this at balderdashy/sails-hook-orm#22, but there are other instances of the same/similar technique in:

• waterline: https://github.com/balderdashy/waterline/blob/master/lib/waterline/methods/stream.js#L379, https://github.com/balderdashy/waterline/blob/master/lib/waterline/methods/stream.js#L431
• skipper: https://github.com/sailshq/skipper/blob/master/lib/skipper.js#L63
• sails core: https://github.com/balderdashy/sails/blob/master/lib/app/private/bootstrap.js#L68, https://github.com/balderdashy/sails/blob/master/lib/hooks/index.js#L211, https://github.com/balderdashy/sails/blob/master/lib/router/bind.js#L233, https://github.com/balderdashy/sails/blob/master/lib/router/bind.js#L369
• machine: https://github.com/node-machine/machine/blob/master/lib/private/normalize-machine-def.js
• parley: https://github.com/mikermcneil/parley/blob/master/lib/parley.js#L373, https://github.com/mikermcneil/parley/blob/master/lib/private/Deferred.js#L1325-L1328
• parasails: https://github.com/mikermcneil/parasails/blob/master/dist/cloud.js#L1200
• anchor: https://github.com/sailshq/anchor/blob/master/lib/rules.js#L303

This suggests there might be surprising behaviour in other places than just datastore.transaction().

I'd be happy to provide PRs for some of these other packages if balderdashy/sails-hook-orm#22 is accepted.

[eashaw]

Hi @alxndrsn, the code in the files you link is to determine whether or not a function is async. Due to the ad hoc way Sails sniffs async functions and function arguments, it doesn't support certain shorthand for passing in functions.
Would you mind explaining how these files relate to this issue, and are you running into issues with this when you use documented syntax?

[alxndrsn]

it doesn't support certain shorthand for passing in functions

@eashaw 👍 that's the cause of the reported bug, which is fixed in my PR

[alxndrsn]

Hi @eashaw, just revisiting this.

Given the expectations around transactional guarantees when working with databases, I think it's dangerously misleading that during may be silently executed outside a database transaction.

It would be great if either a fix can be applied, or the documentation can be updated to warn about this possibility.

I suspect the sails-mysql adapter is also affected by this, although I haven't had a chance to test this yet.

[alxndrsn]

Related: brianc/node-postgres#2561