docs(deferred): the resolve-by-type 3.10 blocker is verified fixable

[lesnik512]

Why

planning/deferred/2026-08-01-resolve-by-type-inline.md listed two blockers. One of them -- the CPython 3.10 coverage-gate failure -- was described with the right mechanism and a prescribed fix, but nobody had checked that the prescription works. Leaving that unverified means the eventual ruling has to re-derive it.

Design

Documentation only; no code. Records the verification and narrows the revisit trigger.

The item prescribed "add a test that reaches that handler by reference rather than through resolve()". Tested on CPython 3.10 with coverage: a by-reference cycle (container.resolve_provider(provider) on a mutual Factory cycle) records container.py:229, 5 runs out of 5. The prescription works.

The mechanism is now stated as general rather than local to this item, because it bit twice: a RecursionError tears down the trace function, so below 3.12 -- where coverage traces instead of using sys.monitoring -- anything executing after the unwind in the same frame goes unrecorded. The same effect hit tests/providers/test_alias.py during 3.2.0 and was fixed there by asserting through pytest.raises(match=) so no line follows the recursion.

Net effect: that bullet costs ~10 lines of test, and the item reduces to its one real question -- whether a duplicated 8-line body is an acceptable standing maintenance cost for ~30 ns per by-type resolve. The revisit trigger now names that as the sole gate.

Non-goals

• Does not implement the inline. The remaining blocker is your judgement call, not a defect I can clear.
• Does not add the by-reference test to the suite. It only earns its place alongside the inline it protects; adding it now would be a test for a line already covered by other means.

Verification

just lint-ci: clean, including the planning frontmatter validator and the Markdown link checker. just index renders the revised summary.

---

Before merging

• Behaviour changed? No code in this PR.
• Rejected an alternative? None.
• Found real work you are not doing now? Already filed -- this PR sharpens that filing.
• just lint-ci passes; just test-ci unaffected (docs only).

[github-actions]

Benchmark

Details

Benchmark suite	Current: 34a1512	Previous: 10e4197	Ratio
benchmarks/test_guard_by_type.py::test_g16_resolve_by_type	2064385.127846483 iter/sec (stddev: 2.4004145219812455e-7)	2664934.4327533874 iter/sec (stddev: 2.0453924587934402e-7)	1.29
benchmarks/test_guard_by_type.py::test_g17_resolve_by_type_large_registry	2639590.943192231 iter/sec (stddev: 5.495991074498385e-8)	3397207.3008231083 iter/sec (stddev: 3.515253036642124e-8)	1.29
benchmarks/test_guard_cold.py::test_g8_cold_first_resolve	24438.630315565366 iter/sec (stddev: 0.00001927031159193012)	34457.92219890785 iter/sec (stddev: 0.00001250363996556651)	1.41
benchmarks/test_guard_concurrency.py::test_g14_concurrent_cached_hit[1]	433.5030893308696 iter/sec (stddev: 0.00005055000968049431)	558.1100634972859 iter/sec (stddev: 0.00003091000939193654)	1.29
benchmarks/test_guard_concurrency.py::test_g14_concurrent_cached_hit[2]	333.4783003645876 iter/sec (stddev: 0.0003057140533577134)	519.8167188978247 iter/sec (stddev: 0.00002291786749641334)	1.56
benchmarks/test_guard_concurrency.py::test_g14_concurrent_cached_hit[4]	373.77639061561035 iter/sec (stddev: 0.00004323759553087591)	487.5283154134495 iter/sec (stddev: 0.000024275221844047625)	1.30
benchmarks/test_guard_concurrency.py::test_g15_concurrent_first_resolve[1]	2354.136985739392 iter/sec (stddev: 0.000023407765344366104)	3156.219614815241 iter/sec (stddev: 0.000019244990000459958)	1.34
benchmarks/test_guard_concurrency.py::test_g15_concurrent_first_resolve[2]	1667.1410145958066 iter/sec (stddev: 0.0003199433825698524)	2257.523026171822 iter/sec (stddev: 0.0002606590779334005)	1.35
benchmarks/test_guard_concurrency.py::test_g15_concurrent_first_resolve[4]	1183.92205436033 iter/sec (stddev: 0.00003768170938956927)	1606.7510322547134 iter/sec (stddev: 0.00002783438307573802)	1.36
benchmarks/test_guard_lifecycle.py::test_g6_build_child_container	674839.2444032873 iter/sec (stddev: 4.675021321916907e-7)	822037.5157239352 iter/sec (stddev: 3.1891795312478927e-7)	1.22
benchmarks/test_guard_lifecycle.py::test_g6b_build_child_container_auto_scope	657156.5142697517 iter/sec (stddev: 4.1069711512516813e-7)	771336.8122861808 iter/sec (stddev: 3.1678881771787854e-7)	1.17
benchmarks/test_guard_lifecycle.py::test_g7_request_lifecycle_batch	2354.2483317098254 iter/sec (stddev: 0.00002542889305555835)	2993.4020982555853 iter/sec (stddev: 0.000007253408199680305)	1.27
benchmarks/test_guard_lifecycle.py::test_g7c_event_loop_floor_control	62881.611715612926 iter/sec (stddev: 0.0000018394011401584951)	79708.79137273741 iter/sec (stddev: 0.000001039243454664696)	1.27
benchmarks/test_guard_lifecycle.py::test_g13_teardown_at_scale	46460.42034740414 iter/sec (stddev: 0.0000024645242486111925)	56257.952885391795 iter/sec (stddev: 0.0000013465812775314434)	1.21
benchmarks/test_guard_resolve.py::test_g1_transient_resolve	1319295.9407439134 iter/sec (stddev: 4.979991785781972e-7)	1747734.83507298 iter/sec (stddev: 2.8841851032267993e-7)	1.32
benchmarks/test_guard_resolve.py::test_g2_cached_resolve	3356699.199250291 iter/sec (stddev: 4.408708169677978e-8)	4357961.233786322 iter/sec (stddev: 2.6410877546784392e-8)	1.30
benchmarks/test_guard_resolve.py::test_g3_deep_chain	503695.38403794623 iter/sec (stddev: 6.958598765035056e-7)	673594.2354822385 iter/sec (stddev: 3.4804824265902755e-7)	1.34
benchmarks/test_guard_resolve.py::test_g4_wide_resolve	326086.2365644157 iter/sec (stddev: 6.776927342690324e-7)	417391.54305801156 iter/sec (stddev: 4.911643485201084e-7)	1.28
benchmarks/test_guard_resolve.py::test_g5_cross_scope	1160404.9824932516 iter/sec (stddev: 3.2672185919541476e-7)	1508296.1372473787 iter/sec (stddev: 4.283170787265259e-7)	1.30
benchmarks/test_guard_resolve.py::test_g9_context_resolve	642681.4091393034 iter/sec (stddev: 4.7396182471017046e-7)	820287.3021842263 iter/sec (stddev: 3.6388032293586744e-7)	1.28
benchmarks/test_guard_resolve.py::test_g12_override_active_resolve	392052.60010961426 iter/sec (stddev: 4.3099263567186966e-7)	524806.0302587249 iter/sec (stddev: 2.423278963003047e-7)	1.34
benchmarks/test_guard_validate.py::test_g10_validate_deep_chain	27172.95583668484 iter/sec (stddev: 0.000005186062509984844)	39734.771986512744 iter/sec (stddev: 0.0000018412134968865806)	1.46
benchmarks/test_guard_validate.py::test_g11_validate_wide	17266.677771805742 iter/sec (stddev: 0.000004230999884202067)	23576.896559038214 iter/sec (stddev: 0.0000026237038454077014)	1.37

This comment was automatically generated by workflow using github-action-benchmark.