How to check if a transaction returned a rollback error?

[keepsimple1]

diesel/diesel/src/connection/mod.rs

Lines 52 to 54 in 3e8fd4d

	/// the original error will be returned, otherwise the error generated by the rollback
	/// will be returned. In the second case the connection should be considered broken
	/// as it contains a uncommitted unabortable open transaction.

Referring to the above doc comment, how do we check if a transaction hit the second case, i.e. returned an error from the rollback?

[weiznich]

There is currently no way to actually check in a general way if the rollback was successful or not, as this could return nearly every error from a connection. I would be open for improvements here.

[keepsimple1]

That would be an solution, but I would likely wrap a diesel::result::Error as inner type of RollbackError.

Did you mean not to use Box? Currently I'm wrapping a Box<diesel::result::Error> as inner type of RollbackError. Rust seems not to allow me to wrap without Box.

Mind opening a PR for this? That should include a documentation change for Connection::transaction mentioning that this error type is returned for rollback errors.

Will do.

[weiznich]

Did you mean not to use Box? Currently I'm wrapping a Boxdiesel::result::Error as inner type of RollbackError. Rust seems not to allow me to wrap without Box.

That error message is correct, Box is required here. I did misread the type as Box<dyn std::error:Error>, so that's just a mistake on my side. Sorry for the confusion.

[keepsimple1]

Thanks for confirming. No problem :)

[keepsimple1]

Followed up in issue #2810 and PR #2811. Thanks for merging the PR.

[weiznich]

Thanks for writing that PR. Such contributions are always welcome 🎉