fix: honor boolean operators in -k snapshot selection

[frenck]

Description

syrupy reimplemented the pytest -k keyword expression with a hand rolled matcher (report.Expression) that flattened the expression into a set of tokens and returned true if any token was a substring of the snapshot name. This ignored the and/or/not and parenthesis operators entirely.

As a result, a negated expression like -k 'not one' treated one as a positive match, so the deselected test_parametrized[one] snapshot was considered unused. On a normal run that reports a spurious unused snapshot (and fails the suite), and with --snapshot-update the snapshot is then deleted, which is data loss.

Minimal reproduction (from #770), no pytest-bdd required:

import pytest

@pytest.mark.parametrize("param", ["one", "two", "three"])
def test_parametrized(param, snapshot):
    assert param == snapshot

pytest --snapshot-update          # writes 3 snapshots
pytest -k 'not one'               # before: "1 snapshot unused"; after: clean
pytest --snapshot-update -k 'not one'   # before: deletes test_parametrized[one]

This delegates parsing and evaluation to pytest's own _pytest.mark.expression.Expression, so selection matches -k exactly, including boolean operators and parentheses. syrupy already requires pytest >= 8, and report.py already imports from _pytest (_pytest.skipping), so this does not introduce a new kind of dependency. Compiled expressions are cached.

Related Issues

• Closes Incorrectly delete unused snapshot in pytest bdd when target run using -k filter #770, unused snapshots incorrectly detected (and deleted on update) when filtering with a negated or compound -k expression.

Checklist

• This PR has sufficient documentation.
• This PR has sufficient test coverage.
• This PR title satisfies semantic convention.

Additional Comments

Added regression tests in tests/integration/test_snapshot_option_filter_keyword.py covering a positive filter, a negated filter, and a negated filter under --snapshot-update (asserting the deselected snapshot is kept). The two negated cases fail on main and pass with this change. Bracket and dash keyword forms that the existing tests rely on (for example -k 'test_used[') keep working, since pytest's parser accepts them as substring matchers. One # type: ignore[arg-type] is needed where syrupy's Callable[[str], bool] matcher meets pytest's keyword-argument-tolerant matcher protocol; keyword matching only ever passes the positional name.

[frenck]

Aah messed up my branches. Sorry, let me quickly fix that.

../Frenck

                       

Blogging my personal ramblings at frenck.dev

[frenck]

Done.

../Frenck

                       

Blogging my personal ramblings at frenck.dev

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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##             main    #1127   +/-   ##
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  Coverage   97.44%   97.44%           
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  Files          24       24           
  Lines        1758     1758           
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  Hits         1713     1713           
  Misses         45       45           

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