Pytest(fix): Plugin imports cleanly under pytest 9.1 (#687)

libtmux's pytest plugin failed to import under pytest 9.1, which
rejects marks applied to fixture functions during plugin import --
before test collection begins. Because the plugin ships as an
installed entry point, this aborted the entire test session for any
downstream project that has libtmux installed and upgrades to pytest
9.1+ (for example, tmuxp). This removes the offending no-op mark and
stops the project from hiding pytest compatibility warnings in its
own configuration.

- **pytest 9.1 plugin import**: Remove the no-op `skipif` mark from the
  `zshrc` fixture. Marks on fixtures never had any effect; the real
  zsh gating lives in `conftest.py` and is unchanged, so behavior is
  identical for zsh and non-zsh users.
- **Visible compatibility warnings**: Drop the project `filterwarnings`
  ignore block (libtmux deprecations, test deprecations, and the
  docutils `frontend.OptionParser` deprecation) so compatibility
  signals surface in development and CI instead of being hidden.
- **Changelog**: Document the fix under the 0.59.x unreleased block.

Fixes #686

Author: tony

CHANGES

@@ -45,6 +45,15 @@ $ uvx --from 'libtmux' --prerelease allow python
 _Notes on the upcoming release will go here._
 <!-- END PLACEHOLDER - ADD NEW CHANGELOG ENTRIES BELOW THIS LINE -->
 
+### Fixes
+
+#### pytest 9.1 compatibility for the pytest plugin (#687)
+
+libtmux's pytest plugin (see {ref}`pytest_plugin`) now imports cleanly
+under pytest 9.1, which began rejecting marks applied to fixture
+functions. Projects that use libtmux's fixtures can upgrade to pytest
+9.1+ without the plugin aborting before test collection.
+
 ## libtmux 0.58.0 (2026-05-23)
 
 libtmux 0.58.0 fixes subprocess output decoding on non-UTF-8 locales.

pyproject.toml

@@ -251,8 +251,3 @@ testpaths = [
 markers = [
   "integration: sphinx integration tests (require full sphinx build)",
 ]
-filterwarnings = [
-  "ignore:The frontend.Option(Parser)? class.*:DeprecationWarning::",
-  "ignore::DeprecationWarning:libtmux.*:",
-  "ignore::DeprecationWarning:tests:",  # tests/
-]

src/libtmux/pytest_plugin.py

@@ -82,7 +82,6 @@ def user_path(home_path: pathlib.Path, home_user_name: str) -> pathlib.Path:
     return p
 
 
-@pytest.mark.skipif(USING_ZSH, reason="Using ZSH")
 @pytest.fixture(scope="session")
 def zshrc(user_path: pathlib.Path) -> pathlib.Path:
     """Suppress ZSH default message.