refactor(tilib): narrow ti_w fixture except → TilibParamError (#218)

[k-yoshimi]

Summary

Completes the ti_w portion of #218 that was deferred in PR #220 (ti_ar only). Mirrors PR #220's commits 23d5b889 + 6ca586f7 on python/tilib/tests/fixtures/ti_w_params.py:

• Add from tilib.errors import TilibParamError import
• Replace 4 except Exception: blocks with except TilibParamError: + updated pragma comment

Closes #218.

Why deferred (until now)

ti_w_params.py only existed on the #219 PR branch (`feat/fixture-parity-215`). #219 merged at `a12982dd` (2026-06-08), bringing the file onto develop. This follow-up was unblocked at that point.

PR #220 description noted this explicit deferral.

Pattern parity with PR #220

Same 4 narrowing sites, same import placement, same pragma comment string ("ierr=1 = invalid name or value; for UNREGISTERED_KEYS this is unknown-name and intentionally silenced"). ti_ar_params.py and ti_w_params.py now have identical exception-handling discipline.

ti_min_params.py has no try/except blocks (verified pre-#220) → #218 is fully closed.

Verified narrowing chain (re-confirmed during #220 review)

• `ti/ti_api.h:27` `TI_ERR_INVALID = 1` ("invalid parameter name or value")
• `ti/ti_param_registry.f90` returns ierr=1 for unknown name AND bad value
• `python/tilib/errors.py:46-51` `_CODE_MAP[1] = TilibParamError`

Other exception classes — `TilibStateError` (ierr=2), `TilibRunError` (ierr=3), `TilibNotImplementedError` (ierr=4) — now propagate instead of being silenced.

Test plan

• Local: `PYTHONPATH=python pytest python/tilib/tests/ --timeout=120 -q` → 43 passed, 3 skipped (no regression)
• CI: python-tests.yml job passes
• Bugbot COMPLETED

Pre-push gate

• ✅ Local pytest: 43/3 (clean)
• ✅ In-house code review: READY-TO-PUSH, no HIGH/MED
• ✅ Codex independent review: READY-TO-PUSH, no HIGH/MED
• ✅ REVIEW_OK marker placed for HEAD `4a986fe3`

🤖 Generated with Claude Code

---

Note

Low Risk
Test-fixture-only change with no production API or runtime logic modified; aligns error handling with an already-shipped ti_ar pattern.

Overview
In ti_w_params.py, the test fixture’s apply / _apply_array helpers now catch TilibParamError instead of bare Exception when calling ti.set_param, with the same pragma comment used in ti_ar_params.py.

Behavior for UNREGISTERED_KEYS is unchanged: invalid-name failures are still swallowed only for those keys. TilibStateError, TilibRunError, and other non-param errors are no longer accidentally suppressed.

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[k-yoshimi]

@cursor review

ti_w narrowing follow-up to #220 (ti_ar). Mirrors PR #220 pattern exactly. Closes #218.

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

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