async def test_explicit_rollback_discards_changes(aconn, svcconn):
"""
Raising a Rollback exception in the middle of a block exits the block and
discards all changes made within that block.
You can raise any of the following:
- Rollback (type)
- Rollback() (instance)
- Rollback(tx) (instance initialised with reference to the transaction)
All of these are equivalent.
"""
async def assert_no_rows():
assert not await inserted(aconn)
assert not inserted(svcconn)
async with aconn.transaction():
await insert_row(aconn, "foo")
raise Rollback
await assert_no_rows()
async with aconn.transaction():
await insert_row(aconn, "foo")
raise Rollback()
await assert_no_rows()
async with aconn.transaction() as tx:
await insert_row(aconn, "foo")
raise Rollback(tx)
await assert_no_rows()
async def test_explicit_rollback_of_outer_transaction(aconn):
"""
Raising a Rollback exception that references an outer transaction will
discard all changes from both inner and outer transaction blocks.
"""
async with aconn.transaction() as outer_tx:
await insert_row(aconn, "outer")
async with aconn.transaction():
await insert_row(aconn, "inner")
raise Rollback(outer_tx)
assert False, "This line of code should be unreachable."
assert not await inserted(aconn)
async def test_named_savepoints_with_repeated_names_works(aconn):
"""
Using the same savepoint name repeatedly works correctly, but bypasses
some sanity checks.
"""
# Works correctly if no inner transactions are rolled back
async with aconn.transaction(force_rollback=True):
async with aconn.transaction("sp"):
await insert_row(aconn, "tx1")
async with aconn.transaction("sp"):
await insert_row(aconn, "tx2")
async with aconn.transaction("sp"):
await insert_row(aconn, "tx3")
assert await inserted(aconn) == {"tx1", "tx2", "tx3"}
# Works correctly if one level of inner transaction is rolled back
async with aconn.transaction(force_rollback=True):
async with aconn.transaction("s1"):
await insert_row(aconn, "tx1")
async with aconn.transaction("s1", force_rollback=True):
await insert_row(aconn, "tx2")
async with aconn.transaction("s1"):
await insert_row(aconn, "tx3")
assert await inserted(aconn) == {"tx1"}
assert await inserted(aconn) == {"tx1"}
# Works correctly if multiple inner transactions are rolled back
# (This scenario mandates releasing savepoints after rolling back to them.)
async with aconn.transaction(force_rollback=True):
async with aconn.transaction("s1"):
await insert_row(aconn, "tx1")
async with aconn.transaction("s1") as tx2:
await insert_row(aconn, "tx2")
async with aconn.transaction("s1"):
await insert_row(aconn, "tx3")
raise Rollback(tx2)
assert await inserted(aconn) == {"tx1"}
assert await inserted(aconn) == {"tx1"}
# Will not (always) catch out-of-order exits
async with aconn.transaction(force_rollback=True):
tx1 = aconn.transaction("s1")
tx2 = aconn.transaction("s1")
await tx1.__aenter__()
await tx2.__aenter__()
await tx1.__aexit__(None, None, None)
await tx2.__aexit__(None, None, None)
def test_explicit_rollback_of_enclosing_tx_outer_tx_unaffected(conn, svcconn):
"""
Rolling-back an enclosing transaction does not impact an outer transaction.
"""
with conn.transaction():
insert_row(conn, "outer-before")
with conn.transaction() as tx_enclosing:
insert_row(conn, "enclosing")
with conn.transaction():
insert_row(conn, "inner")
raise Rollback(tx_enclosing)
insert_row(conn, "outer-after")
assert inserted(conn) == {"outer-before", "outer-after"}
assert not inserted(svcconn) # Not yet committed
# Changes committed
assert inserted(svcconn) == {"outer-before", "outer-after"}