exception handling in knex 0.8.0+ transactions

[jurko-gospodnetic]

When porting our application to use knex 0.8.5 instead of knex 0.7.5 I encountered the following problem:

When creating a transaction, as in:

knex.transaction(function f() {...})...

exceptions thrown by the passed transaction callback f are handled differently than before. In previous knex versions those exceptions would get caught and reported as a rejected transaction promise.

New knex version seems to simply ignore those exceptions, leaving the transaction effectively unresolved forever.

I can easily convert our explicitly thrown exceptions to returning an already rejected promise, but my fear is that some accidental exceptions will cause some transaction to hang and keep holding on to locked database records, thus effectively causing more and more application operations to hang indefinitely.

My suggestion would be to catch those transactions and report them as a rejected transaction promise, same as was done in earlier knex versions.

[jurko-gospodnetic]

+1 :-) nice commit...

[jurko-gospodnetic]

This fix actually broke something else, and even more dangerous - it will reject the transaction promise, but leave the underlying database transaction active.

I have not researched whether that was the case before or not, opened pull request #1257 fixing this.