fix: prevent nested transactions

[betodealmeida]

SUMMARY

The @transaction decorator is used at the command level to ensure a single point of commit/rollback in the application stack. Using the decorator instead of individual calls to db.session.commit() in the stack ensure that requests are atomic.

Unfortunately we have a pattern where commands may call other commands. For example, the UpdateDatabaseCommand.run() method (which is decorated) calls the UpdateSSHTunnelCommand.run() method, which is also decorated with @transaction. This can lead to a situation where the SSH tunnel is updated and committed, but the database update fails and tries to rollback, resulting in an inconsistent state.

To ensure atomicity, this PR modifies the decorator to check if it's inside another decorated method. If so, the decorator returns the function unmodified, behaving as a no-op. With this change, for the example above the SSH tunnel update would only be committed together with the database changes.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TESTING INSTRUCTIONS

Added basic unit tests.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[korbit-ai]

I was unable to post the issues I found. This could be because a force push or squash has changed the commit history since I scanned this pull request. You can get another review by commenting /korbit-review.

[Vitor-Avila]

This is super cool, and I think it's a more elegant solution than calling a run() (or similar method) with or without the @transaction decorator. I've tested this locally (as it will simplify #32231) and confirmed it works 🙌