knowledge: 2 insights — tokio teardown after aborted tasks (abort then await before delete), trailing separator under realpath (macOS resolves file/, glibc/musl ENOTDIR) (2 new pages, 7 amended, 1 folded to #225, 26 plan-gaps retired as local-layer)

[choiyounggi]

Knowledge flush — 3 insight(s) (29 claimed rows: 2 ingested as new pages, 1 folded onto open PR #225, 26 plan-gap rows retired as local-layer)

Run id 20260928-134800-34863 (inherited from the auto-flush parent; lock held under that id). Branch knowledge/choiyounggi-20260928-134840 off origin/main 5986311.

Verified best-practice

1. Deleting a resource that spawned async tasks still use — testing-async-teardown-after-aborted-tasks (NEW, confidence: verified)

Claim. In a test (or shutdown path) that spawned tokio tasks, put teardown on the single path every outcome takes (record the outcome, tear down, then assert / ?), and inside teardown abort and await every reachable JoinHandle before deleting the directory/socket; keep Drop only as the net for failures before the runtime/handles exist.

Sources checked (fetched this run).

• https://docs.rs/tokio/latest/tokio/task/index.html#cancellation — "the task is signalled to shut down next time it yields at an .await point"; "calls to JoinHandle::abort just schedule the task for cancellation, and will return before the cancellation has completed".
• https://docs.rs/tokio/latest/tokio/task/struct.JoinHandle.html — "It is guaranteed that the destructor of the spawned task has finished before task completion is observed via JoinHandle await"; dropping a handle "detaches the associated task"; abort on a started spawn_blocking task "will not have any effect".
• https://docs.rs/tokio/latest/tokio/runtime/struct.Runtime.html#shutdown — on drop, tasks "keep running until they yield. Then they are dropped. They are not guaranteed to run to completion".
• https://doc.rust-lang.org/book/ch11-01-writing-tests.html#using-resultt-e-in-tests — section confirmed present ("We can also write tests that use Result<T, E>!").

Local reproduction (this run, scratch crate under the project's .claude/tmp/, removed afterwards). tokio 1.53.1 from the cargo registry cache, cargo 1.98.0, macOS, multi_thread runtime with 4 workers; a spawned task loops create_dir_all → write → yield_now with ~400 µs of non-yielding work per iteration.

• abort() then remove_dir_all immediately: directory left behind 148/200 runs.
• abort(), await the handle, then remove_dir_all: 0/200.
  The candidate's "why" said an aborted task "still gets one more poll"; the docs say cancellation is scheduled and a running task continues to its next .await — the page uses the documented wording, and the reproduction confirms the effect the candidate observed.

Field evidence (from the harvested row, not re-run). handfish crew-run task t3-swap-flake: RunHandle::shutdown aborted every task but awaited only the bus; leftover .crew-test/<uuid> dirs 1/3 (pass path) and 2/3, 3/3 (panic path) before, 0/12 after.

2. A path ending in a separator passed to realpath / canonicalize — platforms-filesystems-trailing-separator-under-realpath (NEW, confidence: verified)

Claim. When a path that may end in / (or /.) is resolved through realpath(3) and the result decides containment or file-vs-directory, check the raw string before resolving and decide by intent (reject, or require is_dir() after resolving); the resolver's ENOTDIR is platform-dependent.

Sources checked (fetched this run).

• https://pubs.opengroup.org/onlinepubs/9699919799/functions/realpath.html — ERRORS, "shall fail": [ENOTDIR] "… ends with one or more trailing characters and the last pathname component names an existing file that is neither a directory nor a symbolic link to a directory".
• https://doc.rust-lang.org/std/fs/fn.canonicalize.html — "corresponds to the realpath function on Unix and the CreateFile and GetFinalPathNameByHandle functions on Windows".
• https://doc.rust-lang.org/std/path/index.html — "Several methods in this module perform basic path normalization by disregarding repeated separators, non-leading . components, and trailing separators"; "Path::join and PathBuf::push also disregard trailing slashes".
• https://www.gnu.org/software/coreutils/realpath — "It ignores trailing slashes" (the coreutils command; text seen in the search result excerpt of that page — the direct fetch hit HTTP 429 this run).

Local reproduction (this run). libc realpath called through Python ctypes on a regular file out/report.md:

• macOS Darwin 25.1.0: out/report.md/ → Ok(out/report.md), out/report.md/. → Ok(out/report.md).
• python:3-slim (glibc 2.41, docker): both → errno 20 Not a directory.
• python:3-alpine (musl, docker): both → errno 20 Not a directory.
• Rust (cargo 1.98.0, macOS, scratch crate): base.join("out/report.md/") keeps the slash (ends_with(is_separator) == true), std::fs::canonicalize → Ok(…/out/report.md); Path::new("out/report.md/") == Path::new("out/report.md") → true.
  The /. suffix divergence (missed by ends_with(is_separator)) was found in the reproduction and added as an edge row.

Field evidence (from the harvested row). handfish t3-swap-flake: containment accepted …/out/report.md/ on macOS; guard pinned by test path_entry_with_trailing_slash_is_missing_file_not_found; an auditor's mutation removing the guard turned it red.

3. Kotlin top-level helper shadowed by a receiver member inside apply {} — FOLDED onto open PR #225

Claim. Name fixture helpers so they cannot collide with members of the fakes they are used against, or call them outside the apply block. Already carried by PR #225's page backend-java-kotlin-implicit-receiver-shadowing-in-scope-functions (sources: kotlinlang overload-resolution spec, scope-functions docs; verified there). The candidate's unique addition — a suspend member called inside runTest compiles cleanly and fails only at runtime with the fake's stub error (NotImplementedError) — was not in that page (its edge row covered only the non-coroutine caller, which is a compile error). Pushed as one commit to that PR's branch: 0708082 on knowledge/choiyounggi-20260928-082803 (one edge row + one field-evidence line: CalendarViewModelTest, 3 failures → trip() renamed makeTrip() → 14/14). Not re-ingested here.

Existing-layer check

Pages read: testing-async-async-testing, testing-data-artifact-leakage-from-a-suite, testing-data-test-data-and-isolation, security-input-validation-at-trust-boundaries, infrastructure-config-path-valued-config, platforms-tools-bsd-vs-gnu-cli, platforms-filesystems-paths-case-and-line-endings, platforms-filesystems-unix-domain-socket-path-length

Also read: INDEX.md, wiki/testing/index.md, wiki/platforms/index.md, wiki/security/index.md, wiki/backend/index.md (routing), templates/page.md, AGENTS.md format rules, log.md tail.

Semantic dedupe (wiki_search, k=5):

• Insight 1 trigger → top hits: artifact-leakage-from-a-suite (edge "Cleanup exists but does not run on failure", 0.780), test-data-and-isolation (0.772), testcontainers-reaper (0.770), artifact-leakage directive rows (0.770, 0.764). None covers the async-runtime mechanism (abort is asynchronous; a running task recreates the path). artifact-leakage's edge row covers the panic-skips-trailing-cleanup half only and points at a fixture teardown as the fix — which is the racy Drop in the async case. Verdict: new page, with an edge row on artifact-leakage and on async-testing pointing to it. No conflicting directive found: the new page extends "teardown that runs on failure too" with the ordering the runtime requires.
• Insight 2 trigger → top hits: paths-case-and-line-endings (0.801, "use the language's path API"), validation-at-trust-boundaries (0.785, "Canonicalize … then verify the resolved path starts with the base prefix"), unset-versus-empty-parameters (0.775), paths-case edge (0.760), unix-domain-socket-path-length (0.751). validation-at-trust-boundaries prescribes canonicalize-then-prefix-check; the new page does not contradict it — it adds the trailing-separator rule the canonicalize step needs to be platform-independent. Verdict: new page; edge rows added on validation-at-trust-boundaries and bsd-vs-gnu-cli (the libc divergence, as opposed to the coreutils one already on that page).
• Grep sweep of merged wiki/ for JoinHandle|abort()|tokio, canonicalize|realpath|trailing (slash|separator)|path traversal|ENOTDIR: no page owns either trigger (hits were unrelated mentions in frontend/node/testing-quality pages, bsd-vs-gnu-cli's readlink -f row, unix-domain-socket-path-length's "realpath can lengthen a path" row).

Merged vs created: 2 pages created; 0 merged. Amended: async-testing (edge row), artifact-leakage-from-a-suite (edge row + related), validation-at-trust-boundaries (edge row + related), bsd-vs-gnu-cli (edge row + related), test-data-and-isolation (related), paths-case-and-line-endings (related), path-valued-config (related). Domain indexes: testing (async section), platforms (filesystems section). log.md: 2 ingest lines.

Deferred back-link: async-testing.md's related: line is rewritten by open PR #226 — not touched here (the new page links to async-testing one way; the edge row on async-testing carries the inline [id] link). Expected merge overlap: wiki/testing/index.md async section — PR #226 also appends one row after async-testing; both rows are keepable, adjacent-line conflict only.

Lint run on the checkout (this branch): node scripts/wiki-structure-checks.js wiki → pages: 355, indexes: 13, findings: 0 (after removing a related: id that pointed at PR #226's not-yet-merged page — that cross-link is deferred until #226 lands); node scripts/wiki-lint-prohibitions.js → directives: 79, compliant: 79, violations: 0; node scripts/wiki-lint-model-era.js wiki → 6 pre-existing revalidate rows on other pages, none on the two new ones. Banned-qualifier grep on both new pages: no hits. Body lines: 74 and 76 (≤120).

Open-PR check

Open knowledge/* heads (listed with gh pr list --search "head:knowledge/", then git fetch + git diff --stat origin/main origin/<head> -- wiki/):

• knowledge: 1 insight — a native addon has no .node after bun install: blocked vs failed lifecycle script, bun pm untrusted/trust, rebuild under the launcher's runtime (1 new page, 5 back-links, 7 plan-gaps retired as local-layer) #227 knowledge/choiyounggi-20260928-103056 — platforms/toolchains native-addon page + back-links. No overlap with any candidate. Touches wiki/platforms/index.md (toolchains section) — different section from my filesystems row.
• knowledge: 2 insights — park a transient async state behind a test-controlled gate, a PASS body that records a surviving mutant is a finding (1 new page, 2 amended, 26 plan-gaps retired) #226 knowledge/choiyounggi-20260928-092831 — testing/async transient-state-behind-a-controlled-gate (parking a transient state behind a test-controlled gate; tokio sources) + edits to async-testing.md (Do-this table row + related:) and testing/index.md. Read the page: it covers observing mid-run state before a finisher wipes it, not tearing down after tasks; its edge row on the JoinHandle await guarantee is the post-wipe ordering point, which my page cites for the opposite direction (delete after the await). Insight 1 verdict: new (related-linked both ways from my side only; their related: line is theirs to rewrite). Insight 2/3: no overlap.
• knowledge: 12 insights — fake IntersectionObserver under whileInView, concurrent optimistic PATCHes, buildConfigField as Java source, kotlinx coerceInputValues enum defaults, Kotlin implicit-receiver shadowing, self-hosted model load latency, alias-table contract tests, scrub vs timeScale (7 new pages, 1 amended, 77 plan-gaps retired) #225 knowledge/choiyounggi-20260928-082803 — 12 insights incl. backend/java/kotlin/implicit-receiver-shadowing-in-scope-functions. Insight 3 verdict: fold — same trigger and directive; pushed the unique runTest/suspend edge row + second field evidence to that branch (commit 0708082). Insight 1/2: no overlap (its testing pages are fake-intersection-observer and alias-table-contract-tests).
• knowledge: 15 insights — gitignore re-inclusion, union-merge reassembly, hook input fields, silenced-write redirection, jq unicode escape, EPIPE write ordering, fake-server forward-before-reply, shared-helper invariant (8 new pages, 5 amended, 100 plan-gaps retired) #223 knowledge/choiyounggi-20260927-220735 — 15 insights (gitignore, jq, shell redirection, hook fields, fake-server, shared-helper invariant, WebMCP retirements). No overlap with any candidate; touches wiki/platforms/index.md (shells/tools sections) and wiki/testing/index.md (strategy/quality sections), none of the pages I amended.

Per-candidate: insight 1 → new; insight 2 → new; insight 3 → fold (#225).

Routing decision

• Insight 1 → testing/async/teardown-after-aborted-tasks.md (id testing-async-teardown-after-aborted-tasks, applies_to: [rust, general]). Category async ("testing async code") fits; data (artifact leakage) is the symptom page and now links here. General layer: the directive names tokio's documented primitives, no repository files.
• Insight 2 → platforms/filesystems/trailing-separator-under-realpath.md (id platforms-filesystems-trailing-separator-under-realpath, applies_to: [general, rust]). platforms owns "OS-level differences that break code moving between macOS, Linux"; filesystems is the existing category (no new category). Not security/input because the mechanism is a libc divergence that also bites non-security file/dir checks; security's page gets the edge row instead. Not backend because backend has no rust subtree and the divergence is language-independent (reproduced through ctypes and Rust).
• Insight 3 → no page here; folded to knowledge: 12 insights — fake IntersectionObserver under whileInView, concurrent optimistic PATCHes, buildConfigField as Java source, kotlinx coerceInputValues enum defaults, Kotlin implicit-receiver shadowing, self-hosted model load latency, alias-table contract tests, scrub vs timeScale (7 new pages, 1 amended, 77 plan-gaps retired) #225's backend/java/kotlin/implicit-receiver-shadowing-in-scope-functions.md.

No new category.

Local-layer candidates

26 plan-gap rows (all wiki-plan Phase B found no wiki page for this decision), each a one-repository design record whose directive names that repo's own files, constants, RFC numbers or Gradle pins; retired as local-layer, none ingested here. Run wiki-ingest inside each project if the team wants them in its wiki-local/:

seagrass (linkly), task t177-numeric-guard-predicate — 8 rows:

• 857a9c208d359757 AST NumericPredicate + NUMERIC_PREDICATE_KINDS table relocation → wiki-local/backend/dsl/numeric-predicate-ast-and-reserved-words.md
• a682672e179db2c9 predicate allowed inside and → wiki-local/backend/dsl/numeric-predicate-inside-and.md
• 4e812c39753bdfdb mode A truth table / collector entry / And-loop dispatch → wiki-local/backend/dsl/numeric-predicate-runtime-truth-table.md
• 4d2e49a35884f3a2 RFC-0050 Draft status and Updates chain → wiki-local/qa/rfc-process/draft-rfc-updates-chain.md
• 7ea992c6e8d75ee1 vocab manifest exposure of both kind tables → wiki-local/backend/dsl/vocab-manifest-keyword-tables.md
• c2e7bd7c0e686db2 RFC_ROUTES / README x2 / CHANGELOG registries → wiki-local/qa/document-verification/rfc-registry-edits.md
• c1590d9a2589c4e4 golden-adjacent example as RFC prose + interp fixture → wiki-local/testing/strategy/rfc-prose-example-over-committed-example.md
• 65455353e647d7b7 parser/spec need no change → wiki-local/backend/change-impact/generic-condition-call-sites.md

handfish (linkly-crew), t3b-agent-ctrl-drain — 1 row:

• a5df88a34fb09359 unserved control answered per exit arm → wiki-local/backend/concurrency/unserved-control-reply-per-exit-kind.md

handfish, t7-run-gitflow — 7 rows:

• c5a56580a3d35022 role_harness_cfg flag flip site + unit test → wiki-local/backend/config/role-harness-cfg.md
• 4ac881caab90c7e5 sprint merge site and preconditions → wiki-local/infrastructure/gitflow/sprint-merge-preconditions.md
• 49365920900bd98a -c core.hooksPath=/dev/null on every git call → wiki-local/infrastructure/gitflow/disable-hooks-per-invocation.md (general kernel — "when automation commits on a user's repo, disable all hooks per invocation with core.hooksPath=/dev/null, not --no-verify" — is worth a future general candidate once a session emits it with its own evidence; the row as harvested is a design record)
• cdad68524684790e push policy (fast-forward only, lfs check) → wiki-local/infrastructure/gitflow/push-policy.md
• 16f783345eb7467f project_root None issues zero git commands → wiki-local/testing/quality/git-call-counter-seam.md
• 6e256af812509084 resolving the main branch → wiki-local/infrastructure/gitflow/resolve-main-branch.md
• a298a037475db1c0 merged agent files that self-execute (residual risk) → wiki-local/security/agent-exposure/merged-agent-files-residual-risk.md

dace (linkly-calendar Android), t6a-trip-ui — 10 rows:

• 7068f2146ea1e6b9 Maps key gate isValidKey/readManifestKey → wiki-local/mobile/maps/google-maps-key-gate.md
• 3042cba1f8844f84 who constructs TripViewModel → wiki-local/mobile/architecture/tab-root-receives-viewmodel.md
• d771e774c84744e2 OPTIMIZE_APPLY_FAILED_MESSAGE constant + local state → wiki-local/mobile/presentation/local-error-message-constant.md
• c3868b8e8b2fab3b moveItem/removeItem pure functions → wiki-local/mobile/presentation/itinerary-move-remove.md
• 772f3a2a727f3cfe tripDatesInRange/tripShortDisplay on LocalDate → wiki-local/mobile/presentation/trip-date-helpers.md
• 07729881a03fce5f MarkerComposable badges → wiki-local/mobile/maps/marker-composable-badges.md
• 25c323dfe8e9f66c hand-rolled decodePolyline + test file → wiki-local/mobile/maps/decode-polyline.md
• 8979225a66711966 maps-compose 6.6.0 / play-services-maps 20.0.0 pins from Gradle Module Metadata → wiki-local/mobile/dependencies/maps-compose-pins.md (general kernel — verify a transitive floor from the artifact's .module requires vs strictly, not from an HTTP 200 — is a future general candidate)
• eef21f20e6149557 MapStyle.light null on parse failure → wiki-local/mobile/maps/map-style-null-fallback.md
• 081eb80b1695e007 .orchestration-notes/t6a-trip-ui.md contents → wiki-local/infrastructure/agent-orchestration/task-notes-file.md

Count check: 8 + 1 + 7 + 10 = 26.