Subject: 29.1; with-sqlite-transaction commits on exception rather than rolling back

From: Vasilij Schneidermann <[email-masked]>
Date: Mon, 13 Nov 2023 01:47:01 +0100

During experimentation with built-in SQLite support, I've noticed that
if I use `with-sqlite-transaction' and there is a mistake in the body,
`sqlite-commit' is executed rather than `sqlite-rollback', thereby
committing the changes done up to the error instead of backing out.

This appears to be unusual behavior. From my quick research, the
following SQLite bindings in other languages have an equivalent to
`with-sqlite-transaction' and back out changes on error:

- CHICKEN Scheme:
  https://api.call-cc.org/5/doc/sql-de-lite#def:with-transaction
- Go: https://pkg.go.dev/database/sql#Conn.BeginTx
- Racket: https://docs.racket-lang.org/db/query-api.html#%28def._%28%28lib._db%2Fbase..rkt%29._call-with-transaction%29%29
- Ruby: https://www.rubydoc.info/gems/sqlite3/1.4.2/SQLite3/Database#transaction-instance_method
- Rust:
  https://docs.rs/rusqlite/latest/rusqlite/struct.Connection.html#method.transaction

In languages not offering an equivalent API, it was instead recommended
to manually issue BEGIN/COMMIT/ROLLBACK statements. But given that
`with-sqlite-transaction' exists, it would be less confusing to make it
back out on exception (and re-raise the original error).

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