Errors

Every failure is a FrostlakeError, so e isa FrostlakeError catches all of them. The subtype tells what happened:

• QueryError: the engine refused the statement. message is the engine's text, unmodified.
• ConnectionError: no answer arrived. The host refused the connection, the socket failed, the deadline passed, or a proxy answered with something that is not a Frostlake response. The statement's outcome is unknown, so do not retry it blindly: re-running an INSERT could duplicate it.
• SessionLostError: the engine no longer held the connection's session, and the statement did not run, nor was it re-run: the lost session held an open transaction or context of the caller's own. The connection stays usable; see Session lifetime.
• UsageError: the driver did not send anything. Causes include a malformed DSN, a closed connection, a value with no SQL equivalent, or an argument count that does not match the placeholders.

QueryError.statement and SessionLostError.statement hold the rendered SQL with every parameter inlined, so a bound password appears in them verbatim. The error's printed form and message do not include it: log those, and treat statement as sensitive.