Errors within a transaction are lost

[pjlegato]

If a statement within a multi-statement transaction causes an error, such as an INSERT that does not provide a value for a NOT NULL column, this error is currently lost. It should probably throw an exception back to the caller.

[pjlegato]

The simple test case I wrote does indeed throw an error as expected, so it is not quite what I described above; it's something more complex. I'm working on a self-contained test case that reproduces the issue where a transaction fails silently.