fix: unbreak CI — pyarrow 25 added binary_view compare kernels, tripping the strict-xfail canary

[NickCrews]

Problem

Every PR's CI currently fails with:

FAILED tests/fast/arrow/test_filter_pushdown.py::TestCanaries::test_pyarrow_gains_binary_view_filter_support - [XPASS(strict)] pyarrow does not yet implement binary_view filter compare kernels

(example run: https://github.com/duckdb/duckdb-python/actions/runs/29216913610, from #409 — unrelated to that PR's content)

CI installs the latest pyarrow at run time, and pyarrow 25.0.0 added binary_view compare kernels. The canary body only exercised scanner construction, which no longer raises, so the strict xfail XPASSes and fails CI for everyone. Same spirit as #541: unbreak CI on main.

What actually changed in pyarrow (verified empirically on 23.0.1, 24.0.0, 25.0.0)

pyarrow	scanner(filter=binary_view ==)	executing the scan
≤ 24.0.0	raises ArrowNotImplementedError ('equal' has no binary_view kernel)	n/a
25.0.0	succeeds	raises ArrowNotImplementedError ('array_filter' has no binary_view kernel)

So pyarrow's support is still only partial — a binary_view filter still cannot be executed end-to-end, and DuckDB's post-scan fallback for view types (covered by TestUnsupportedTypes) is still required. (string_view is unchanged: even scanner construction still raises on 25.0.0.)

Fix

• test_pyarrow_gains_binary_view_filter_support is converted from a strict xfail into a version-gated assertion (using the file's existing packaging.version.Version convention):

  • pyarrow < 25: scanner construction must raise ArrowNotImplementedError
  • pyarrow ≥ 25: scanner construction must succeed, and executing the scan must raise ArrowNotImplementedError

  Either branch failing means pyarrow moved again, preserving the canary's purpose: it fires when pyarrow gains full binary_view filter support and the post-scan fallback should be removed.

• The sibling string_view canary keeps its strict xfail but now also executes the scanner, so when pyarrow lands string_view compare kernels ahead of filter kernels (as just happened for binary_view), it will keep xfailing instead of breaking CI again; it only xpasses on full end-to-end support.

Verification

• Full tests/fast/arrow/test_filter_pushdown.py with pyarrow 23.0.1 (the repo's minimum for Python ≥ 3.10): 541 passed, 7 xfailed.
• TestCanaries + TestUnsupportedTypes with pyarrow 25.0.0: 10 passed, 7 xfailed — the view-type post-scan fallback still yields correct results on latest pyarrow.
• ruff check / ruff format --check clean.

Judgment call: rather than simply widening the xfail, the ≥ 25 branch pins down the new partial-support behaviour (construction works, execution doesn't), which documents exactly where pyarrow stands and what the fallback still protects against.

🤖 Generated with Claude Code

[NickCrews]

closing because I think #543 might be the real fix here? Anyway, this was generated by claude and I don't think I fully understand it, so I can't really verify this is the right direction, and don't want to waste maintainers time with slop.