Add Close wrappers to PGconn

[JelteF]

This adds wrappers around the Close portal/prepared statement functions that got added in libpq version 17: postgres/postgres@28b5726

Related to #589, but this doesn't start using these new functions yet to close prepared statements.

[dvarrazzo]

Hello, thank you for this MR!

Can you please add relevant tests to tests/pq/test_exec.py and tests/pq/test_async.py? These test modules seem to contain tests for the most closely related functions.

You can use the pytest.mark.libpq marker to parametrize tests according to the libpq version. See the tests for hostaddr for instance, which are only available since libpq 12:

psycopg/tests/pq/test_pgconn.py

Lines 222 to 234 in 1f56776

	@pytest.mark.libpq(">= 12")
	def test_hostaddr(pgconn):
	# not in info
	assert isinstance(pgconn.hostaddr, bytes), pgconn.hostaddr
	pgconn.finish()
	with pytest.raises(psycopg.OperationalError):
	pgconn.hostaddr
	@pytest.mark.libpq("< 12")
	def test_hostaddr_missing(pgconn):
	with pytest.raises(psycopg.NotSupportedError):
	pgconn.hostaddr

[dvarrazzo]

Rebased on master to fix the lint problem with mypy.

[dvarrazzo]

Mypy is still failing, but this time it's legit:

psycopg/psycopg/errors.py:214: error: Incompatible return value type (got "FinishedPGconn", expected "PGconn")  [return-value]
Found 1 error in 1 file (checked 180 source files)

That's because FinishedPGconn doesn't have the methods you added, therefore it doesn't implement the PGconn interface anymore. Just adding them, failing like the other ones, will be enough :)

[JelteF]

Added tests are and mypy should now be fixed.

[dlax]

With suggested changes, fixing the python implementation:

$ env PSYCOPG_IMPL=c pytest tests/pq -k close -vv
========================================================= test session starts ==========================================================
platform linux -- Python 3.11.2, pytest-7.3.1, pluggy-1.0.0 -- /home/denis/src/psycopg3/.venv/bin/python
cachedir: .pytest_cache
default selector: EpollSelector
Server version: PostgreSQL 15.3 (Debian 15.3-0+deb12u1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
libpq wrapper implementation: c
libpq used: 170000
libpq compiled: 170000
rootdir: /home/denis/src/psycopg3
configfile: pyproject.toml
plugins: cov-4.0.0, anyio-3.6.2
collected 164 items / 159 deselected / 5 selected                                                                                      

tests/pq/test_async.py::test_send_close_prepared PASSED                                                                          [ 20%]
tests/pq/test_async.py::test_send_close_portal PASSED                                                                            [ 40%]
tests/pq/test_exec.py::test_close_prepared PASSED                                                                                [ 60%]
tests/pq/test_exec.py::test_close_portal PASSED                                                                                  [ 80%]
tests/pq/test_pgconn.py::test_encrypt_password_closed PASSED                                                                     [100%]

================================================== 5 passed, 159 deselected in 0.21s ===================================================
$ env PSYCOPG_IMPL=python pytest tests/pq -k close -vv
========================================================= test session starts ==========================================================
platform linux -- Python 3.11.2, pytest-7.3.1, pluggy-1.0.0 -- /home/denis/src/psycopg3/.venv/bin/python
cachedir: .pytest_cache
default selector: EpollSelector
Server version: PostgreSQL 15.3 (Debian 15.3-0+deb12u1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
libpq wrapper implementation: python
libpq used: 170000
libpq compiled: 170000
rootdir: /home/denis/src/psycopg3
configfile: pyproject.toml
plugins: cov-4.0.0, anyio-3.6.2
collected 164 items / 159 deselected / 5 selected                                                                                      

tests/pq/test_async.py::test_send_close_prepared PASSED                                                                          [ 20%]
tests/pq/test_async.py::test_send_close_portal PASSED                                                                            [ 40%]
tests/pq/test_exec.py::test_close_prepared PASSED                                                                                [ 60%]
tests/pq/test_exec.py::test_close_portal PASSED                                                                                  [ 80%]
tests/pq/test_pgconn.py::test_encrypt_password_closed PASSED                                                                     [100%]

================================================== 5 passed, 159 deselected in 0.19s ===================================================

[dvarrazzo]

@JelteF thank you very much for this feature! Do you know if there is the possibility already to install libpq 17 on the clients for testing?

This is done by tools/build/ci_install_libpq.sh and by looking at this test run it only picked up 15.3.

At the moment we can configure the CI specifying to use the oldest/newest version available in the runner package manager. Is there an easy version that you know to test with something before being released?

If there is no easy access to a package maybe we should add something like master here to install from source.