Breaks with pytest 7 due to private imports

[The-Compiler]

In pytest-dev/pytest#9415, we discovered that this plugin breaks with pytest 7.0.0rc1:

  File ".../pytest_postgresql/factories/process.py", line 27, in <module>
    from _pytest.tmpdir import TempdirFactory
ImportError: cannot import name 'TempdirFactory' from '_pytest.tmpdir' (/usr/lib/python3.10/site-packages/_pytest/tmpdir.py)

This is due to this class moving to a different place in pytest internally. Other places use similar private imports which still work, for now:

tests/test_postgres_options_plugin.py
3:from _pytest.pytester import Pytester

src/pytest_postgresql/config.py
1:from _pytest.fixtures import FixtureRequest

src/pytest_postgresql/plugin.py
22:from _pytest.config.argparsing import Parser

tests/test_executor.py
5:from _pytest.fixtures import FixtureRequest

src/pytest_postgresql/factories/client.py
22:from _pytest.fixtures import FixtureRequest

src/pytest_postgresql/factories/noprocess.py
23:from _pytest.fixtures import FixtureRequest

src/pytest_postgresql/factories/process.py
26:from _pytest.fixtures import FixtureRequest
27:from _pytest.tmpdir import TempdirFactory

With pytest 7.0.0, those types become publicly available, so it's recommended to import them from pytest directly instead, perhaps via a small compat layer which can be dropped once support for pytest<7 isn't relevant anymore.

[The-Compiler]

Trivial fix which makes the test work (but the other private imports should be avoided even if they continue to work):

From 64d8b7135cb6cd582b06dbabe4da1ba3d19c8a73 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <me@the-compiler.org>
Date: Tue, 21 Dec 2021 17:43:47 +0100
Subject: [PATCH] Fix pytest 7 compatibility

---
 src/pytest_postgresql/factories/process.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/pytest_postgresql/factories/process.py b/src/pytest_postgresql/factories/process.py
index 0f002c8..017b25c 100644
--- a/src/pytest_postgresql/factories/process.py
+++ b/src/pytest_postgresql/factories/process.py
@@ -23,10 +23,15 @@
 from typing import Union, Callable, List, Iterator, Optional, Tuple, Set
 
 import pytest
-from _pytest.fixtures import FixtureRequest
-from _pytest.tmpdir import TempdirFactory
 from port_for import get_port
 
+try:
+    # pytest 7
+    from pytest import FixtureRequest, TempdirFactory
+except ImportError:
+    from _pytest.fixtures import FixtureRequest
+    from _pytest.tmpdir import TempdirFactory
+
 from pytest_postgresql.config import get_config
 from pytest_postgresql.executor import PostgreSQLExecutor
 from pytest_postgresql.janitor import DatabaseJanitor
-- 
2.34.1

[fizyk]

Took a look at pytest changelog, and we can import TmpdirFactory and FixtureRequest from pytest since pytest 6.2.0 Without try...except block.

I'll try to update the imports tomorrow and release a new version that hard requires at least pytest >= 6.2.0

More https://docs.pytest.org/en/6.2.x/changelog.html#improvements

[fizyk]

@The-Compiler I'm not able to import Parser from anywhere else though

[The-Compiler]

Yep, looks like pytest.Parser will only be exposed with the upcoming 7.0.0 release, so you will probably need a try/except for that one for now. Well spotted that the others were available with 6.2.0 already, I missed that one!

[fizyk]

@The-Compiler 7.0.x only deprecates the Parser usage.

I'd come back to this after the 7.0 will get released https://docs.pytest.org/en/7.0.x/changelog.html#deprecations

[The-Compiler]

It deprecates creating the class, which is not something you are doing. It also exposes the class publicly as pytest.Parser for type annotations:

[fizyk]

@The-Compiler the same was the case for TempdirFactory and FixtureRequest in pytest 6.2: https://docs.pytest.org/en/6.2.x/changelog.html#deprecations

7.0 exposes Parser in similar fashion the 6.2 exposes the two types above https://docs.pytest.org/en/7.0.x/changelog.html#features

I'm puzzled though, as it seems that the TempdirFactory disappeared from the pytest 7.0.0.rc1