Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.77%. Comparing base (44433dd) to head (bd36427).

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##           master    #1785   +/-   ##
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  Coverage   99.77%   99.77%           
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  Files          33       33           
  Lines        3536     3536           
  Branches      498      498           
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  Hits         3528     3528           
  Misses          5        5           
  Partials        3        3           

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Merging this PR will not alter performance

✅ 18 untouched benchmarks
🆕 3 new benchmarks

Performance Changes

Comparing bluetoothbot:koan/bench-mark-records-to-expire (bd36427) with master (44433dd)

@bluetoothbot Rr

Rebase with requested adjustments

Branch koan/bench-mark-records-to-expire was rebased onto master and review feedback was applied.

Stats

1 file changed, 123 insertions(+)

• Already-solved check: skipped (Claude call failed)
• Rebased koan/bench-mark-records-to-expire onto upstream/master
• Review feedback step failed: Exit code 1: no stderr | stdout: You've hit your session limit · resets 6:30pm (UTC) | stdout: You've hit your session limit · resets 6:30pm (UTC)
• Pre-push CI check: previous run passed
• Force-pushed koan/bench-mark-records-to-expire to origin
• CI check enqueued in ## CI (async)

CI status

CI will be checked asynchronously.

Automated by Kōan

@bluetoothbot Rr

PR Review — test: add benchmarks for cache mark-to-expire path (#1780)

The three benchmarks have a load-bearing correctness bug that the CodSpeed report itself surfaces: all_stale and none_stale measure identical 120.2 µs because async_mark_unique_records_older_than_1s_to_expire mutates each cached record's created field on the first call, and CodSpeed re-runs the closure many times per measurement against the shared outer-scope cache. Iterations 2..N hit the cheap age-check-and-skip path, so the "worst case" benchmark is really measuring the scan-only path, and there's no actual baseline for the copy-on-expire follow-up (#1780) to compare against. @bdraco's review identified both halves of this — reset state between iterations, and don't pay the async_add_records cost in the measured body. The fix is benchmark.pedantic(setup=..., rounds=N, iterations=1). Docstrings also carry more narrative than CLAUDE.md asks for. Blocking until the pedantic shape lands and the new CodSpeed numbers actually diverge between stale and fresh.

🔴 Blocking

This benchmark doesn't measure what its docstring claims. async_mark_unique_records_older_than_1s_to_expire calls _async_set_created_ttl(record, now, 1), which mutates the cached record in place to created=now, ttl=1 (see _cache.py:343-348). CodSpeed's walltime harness runs the decorated closure many times per measurement — and since cache, the records, and now are all captured from the outer scope, on iterations 2..N the age check (now - created_double > _ONE_SECOND) is (now - now > 1000) == False, so the mutation branch is skipped entirely. Only the first call hits the worst case.

The CodSpeed report on this PR is the smoking gun: test_mark_to_expire_1000_records_all_stale and test_mark_to_expire_1000_records_none_stale both report 120.2 µs — identical to the tenth of a microsecond. If the all-stale path were actually being measured it would be substantially slower (1000 extra _async_add calls per iteration). The reported number is essentially just the scan + age-check cost in both cases, which means the "baseline for copy-on-expire follow-up" this PR is meant to provide doesn't exist.

Fix: reset cache state before each measured iteration without including setup in the timing. The standard pytest-benchmark/pytest-codspeed idiom is benchmark.pedantic with a setup callable, e.g.

records = [DNSAddress(name, _TYPE_A, _UNIQUE_CLASS, 120, _ipv4_bytes(i), created=now - 5_000) for i in range(1000)]

def _setup():
    cache = DNSCache()
    cache.async_add_records(records)
    return (cache, unique_types, answers, now), {}

benchmark.pedantic(
    DNSCache.async_mark_unique_records_older_than_1s_to_expire,
    setup=_setup,
    rounds=50,
    iterations=1,
)

This keeps the async_add_records cost out of the measurement (per @bdraco's second point) while ensuring every measured call sees fresh, stale records. Apply the same pattern to test_mark_to_expire_many_unique_types. test_mark_to_expire_1000_records_none_stale is the only one of the three that's stable across iterations as written — but for consistency it should use the same pedantic shape.

@benchmark
def _mark() -> None:
    cache.async_mark_unique_records_older_than_1s_to_expire(unique_types, answers, now)

Same root cause as the first benchmark: the 100 cached PTR records start with created=now - 5_000, the first call mutates all of them to created=now, ttl=1, and every subsequent measured iteration falls out of the mutation branch. The 135.1 µs CodSpeed number is dominated by the outer loop over 100 unique_types triplets and the scan, not by the mutation cost the test is meant to expose. Same fix — benchmark.pedantic with a setup callable that rebuilds the cache between rounds.

🟢 Suggestions

Per CLAUDE.md, test docstrings should pin what the test asserts in one sentence — not retell the production-side story. The line-number reference (_cache.py line ~345) will rot the moment the file shifts, and the issue cross-reference ("follow-up to issue #1780") belongs in the PR description rather than the source. Consider trimming to a single line: "Benchmarks for DNSCache.async_mark_unique_records_older_than_1s_to_expire." Same goes for the per-test docstrings — they each include rationale ("the delta to the all-stale case is the mutation+re-add tax we'd avoid by switching to copy-on-expire") that's PR-body material.

Checklist

• Benchmarks measure the claimed code path — critical ＃1, critical ＃2
• Setup cost excluded from measured body
• No untested code branches introduced
• Docstrings follow CLAUDE.md (terse, no narrative) — suggestion ＃3
• No Co-Authored-By from automated agents
• No changes outside tests/benchmarks/

Summary

The three benchmarks have a load-bearing correctness bug that the CodSpeed report itself surfaces: all_stale and none_stale measure identical 120.2 µs because async_mark_unique_records_older_than_1s_to_expire mutates each cached record's created field on the first call, and CodSpeed re-runs the closure many times per measurement against the shared outer-scope cache. Iterations 2..N hit the cheap age-check-and-skip path, so the "worst case" benchmark is really measuring the scan-only path, and there's no actual baseline for the copy-on-expire follow-up (#1780) to compare against. @bdraco's review identified both halves of this — reset state between iterations, and don't pay the async_add_records cost in the measured body. The fix is benchmark.pedantic(setup=..., rounds=N, iterations=1). Docstrings also carry more narrative than CLAUDE.md asks for. Blocking until the pedantic shape lands and the new CodSpeed numbers actually diverge between stale and fresh.

To rebase specific severity levels, mention me: @bluetoothbot rebase critical (fixes 🔴 only), @bluetoothbot rebase important (fixes 🔴 + 🟡), or just @bluetoothbot rebase for all.

Automated review by Kōanf6f4a8e

Rebase with requested adjustments

Branch koan/bench-mark-records-to-expire was rebased onto master and review feedback was applied.

Changes applied

• Single-file change, no task tracking needed.

• Summary

• Switched all three benchmarks from the @benchmark decorator to benchmark.pedantic(target, setup=...) per @bdraco's review:
• Iterate once: async_mark_unique_records_older_than_1s_to_expire mutates cached records in place (_async_set_created_ttl(record, now, 1)). With the @benchmark decorator, only the first call did real work — subsequent calls hit records whose created was already reset to now, so the now - created_double > _ONE_SECOND guard skipped the mutation branch. Pedantic mode with default rounds=1, iterations=1 measures exactly one call.
• Setup outside the timed window: each test's _setup callback rebuilds a fresh stale DNSCache per round and returns (cache,), {}. async_add_records is no longer counted toward the measurement.

Stats

1 file changed, 124 insertions(+)

• Already-solved check: negative (confidence=high, reasoning=No commit on master adds benchmarks for DNSCache.async_mark_unique_records_older_than_1s_to_expire; )
• Rebased koan/bench-mark-records-to-expire onto upstream/master
• Applied review feedback
• Pre-push CI check: previous run passed
• Force-pushed koan/bench-mark-records-to-expire to origin
• CI check enqueued in ## CI (async)

CI status

CI will be checked asynchronously.

Automated by Kōan