The column names for a result set were already carried through the
cursor state machine but kept write-only, awaiting a reader. Add the
PEP-249 `Cursor.description` accessor on top of that plumbing: it
returns one 7-tuple per column (only the name populated, which is all
Synapse reads), or `None` when there is no row-returning result set —
before any query, after an error, or for a column-less statement such
as a bare INSERT, matching psycopg2.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Synapse's schema setup (`prepare_database.py`) runs `;`-separated SQL
scripts via the engine's `executescript`. `Cursor.execute` can't serve
those: it `prepare`s the query, and Postgres rejects multiple commands in
a prepared statement.
Add `Cursor.executescript`, which runs the whole script on the simple-query
protocol (`batch_execute`), which does allow multiple statements. It takes
no parameters and produces no fetchable rows.
The script runs inside the connection's *current* transaction (opened
lazily like `execute`) and is left open for the caller to commit. It
deliberately does NOT reproduce the commit-any-pending-transaction-first
behaviour of `sqlite3.executescript` (which psycopg2's engine mirrors with a
leading `COMMIT`). That forced commit actually undercuts the atomicity
`prepare_database` sets out to get — it opens a transaction so "upgrades are
either applied completely, or not at all", but the first script's implicit
commit ends it. Running the script within the ongoing transaction instead
lets successive scripts accumulate and be committed once, which is both
simpler and more correct. The only engine-level piece left to layer on top
is the auto-increment placeholder substitution.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Previously every `tokio_postgres` error became a bare `RuntimeError`. Synapse's
transaction driver, though, branches on the *type* of a database error and on
its `pgcode`: `new_transaction` retries `OperationalError`, retries deadlocks it
recognises via `is_deadlock` (which reads `pgcode`) on a `DatabaseError`, and
`simple_upsert` retries `IntegrityError`. With everything collapsed to
`RuntimeError` none of that fired.
Add just the distinctions Synapse acts on, rather than psycopg2's full PEP-249
hierarchy: `Error` -> `DatabaseError` -> {`OperationalError`, `IntegrityError`},
exposed on the `postgres` submodule, each instance tagged with `pgcode` (the
SQLSTATE string, or `None`). A small classifier maps the SQLSTATE class:
constraint violations (`23`) to `IntegrityError`, connection/resource classes
(`08`/`53`/`57`/`58`) to `OperationalError`, everything else (incl. `40*`
deadlocks, which retry via `pgcode`) to `DatabaseError`. Codeless errors are
split with `is_closed()`: a lost connection is operational, any other (a bad
parameter, a failed connect) is a plain `DatabaseError` so it isn't retried.
Errors surfacing while a result stream is drained (the usual case for an
`INSERT` constraint violation) now route through the same mapping, so they carry
the right class and `pgcode` too.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Add the end-to-end test suite for the Rust DBAPI2 backend, driving the real
tokio-postgres client against a live Postgres server. It is skipped unless
the suite is configured for Postgres (SYNAPSE_POSTGRES), the same switch the
rest of the suite uses.
These cover the behaviours that need a real server rather than the
in-memory fakes the Rust unit tests use: connect (good and bad DSN),
run_interaction (return value, arg/kwarg forwarding, commit on success,
rollback on a Python exception, and recovery after both a Python-raised and
a server-rejected statement, including a constraint violation), cursor
reuse across queries, the fetch_one/fetch_all/fetch_next_batch/rowcount
surface (including batching across a 1000-row result set and the
exhausted-vs-no-active-query error distinction), and value round-trips for
every supported type (NULL, bytea with NUL/high bytes, float4 lossiness,
and an out-of-range int bound to a real int4 column).
A separately-guarded case exercises the libpq default-host fixup by
connecting with a DSN that omits the host.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
