Files
siftlode/backend/app
peter 2fe58073e4 fix(diagnostics): deep-review round 3 — a keyboard owner that is not a Tab trap
Round 2 made the step prompt a blocking layer so that `j` and the `g` chords
would not reach the page behind it. The dialog it sits in gave up its Tab trap
because of that, while the prompt's own replacement trap covered only its own
two controls — so Tab from anywhere else in the dialog (the bar's Screenshot or
Stop, the dialog's own buttons) walked out behind the scrim. `layerStack` now
separates the two questions it had folded into one flag: a layer can own the
keyboard and still leave the Tab trap to the dialog below it. The mirror case,
a dialog opening over the prompt, falls out of the same split.

A send's claim is now a lease with an owner. Every progress report re-stamps
it, so a send slower than the lease cannot lose it while it is still running,
and only the send that took a claim can give it back. The issue_create audit
row is staged inside the send and rides the same checkpoint as `issue_url`, so
the trail cannot be missing for an issue that exists. The attachment-name
prefix has one definition, shared by the producer and both readers.

A running send is reported to the UI. A reload or a second tab used to render
it exactly like a send that STOPPED, and offered a retry the server was certain
to refuse; the composer now says the report is being sent, holds the draft, and
puts both the retry and Create issue out. The past-sessions list says the same
for the same reason — it is the list a user opens to check on a send, and both
"draft" and "half sent" describe one that died. `/preview` and the retry path
got a pace of their own, and the per-user byte cap took the user-scoped lock
that makes it a cap instead of a guess.

Verified in a real browser on localdev: Tab cycles the whole dialog with the
prompt open, the prompt still swallows the page's keys, and the issue link is
focusable where the composer puts it. All 24 regression tests mutation-checked.
2026-09-20 02:43:56 +02:00
..
2026-06-14 04:40:22 +02:00

Backend conventions

The rules below are already followed across backend/app — they lived only in a few module docstrings (demo.py, userscope.py, routes/_common.py) until this file collected them (E3 S3, B-core-20). When you add code, match these so the next reader doesn't have to guess "which pattern do I copy".

Module layering

Three layers, by who runs the code — not by feature:

  1. routes/… — request-only. A route module holds HTTP concerns: auth dependencies, request/ response models, status-code mapping, serialization. It owns logic that runs only on a request. Business logic that a request happens to trigger does not live here if anything else runs it too.

  2. plex/, downloads/, sync/, issues/ — domain logic shared by more than one caller. Anything the scheduler or the worker runs (not just a request) lives in one of these domain packages, so the route, the worker, and the scheduler share one definition. Examples from this codebase: downloads/service.py owns enqueue + the job state transitions (routes call it); plex/sync.py is run by both the admin route and the scheduler; downloads/pipeline.py is the worker's child pipeline; issues/bundle.py is the one definition of a bug report's files, for the zip export and the tracker.

  3. Flat app/*.py core modules — cross-cutting primitives. auth, sysconfig, quota, audit, notifications, userscope, realtime, ratelimit, progress, logs (the one logging configuration), logsink (its log_events table), diagnostics (a user's consented log level) and debugsession (a recording that tags its user's lines, E16), … are single-file primitives many layers import. They depend on nothing above them (a core module must never import a routes/… module).

Extraction trigger: the SECOND consumer. Keep new logic inline in its first caller. The moment a second caller needs it (a worker as well as a route; a scheduler as well as a route), extract it down a layer — into the relevant domain package, or a flat core module if it's cross-cutting. Don't pre-abstract for a single caller; don't leave shared logic duplicated once there are two.

Transaction ownership

This follows CLAUDE.md's canonical rule verbatim — "the handler/job-wrapper commits; helpers flush (only quota owns its session)" — so read it that way, not as an exception to it. The commit belongs to the operation owner; anything called inside another transaction only stages its change (db.add / flush) and lets the owner commit, so the whole operation is one transaction. audit.record() is the reference: it adds the audit row and the caller commits it together with the mutation it records, so an audit entry can never exist without its change (or vice-versa).

  • The operation owner is usually the route handler. A service.* operation the handler delegates a whole transition to (e.g. service.cancel) is that owner and commits its one transition — it isn't a mid-operation helper. A helper that owns its OWN short-lived session (the worker's jobdb writes, the same carve-out CLAUDE.md grants quota) commits that session. Everything else flushes.
  • SessionLocal is expire_on_commit=False: after a raw UPDATE + commit, an ORM object you already loaded is stale. Read the fresh value from the row (RETURNING, or a re-SELECT), not the ORM attribute — see service.decr_ref_count.

Shared counters and status: do it atomically at the DB

  • Never read-modify-write a shared counter in Python (x.count = x.count + 1). Concurrent sessions lose an update. Use a DB-atomic statement — col = col + 1, or greatest(col - 1, 0) with RETURNING so the caller branches on the post-value under the row lock (service.incr_ref_count / decr_ref_count).
  • Download job status is a JobStatus StrEnum (downloads/status.py), not bare strings. The HOLDING set defines which states hold a MediaAsset (so release accounting stays correct); STOPPED_BY_ROUTE is the route-initiated stop set. A worker child's terminal write goes through service.finalize_if_running (an atomic UPDATE … WHERE status='running') so a finishing child can't resurrect a job a route just stopped.

Config: one home per kind

  • app.config.settings — boot/env config (DB URL, download root, worker concurrency): read once at startup, not user-tunable at runtime.
  • sysconfig.SPECS — the runtime admin knobs (DB-override-or-default). A new admin-tunable value goes in SPECS; don't invent a fourth store. (state.py's maintenance_batch predates this and is slated to fold into sysconfig — do not add more like it.)

The gate

Everything below must be green before a change is done (run via siftlode check): ruff (backend) · tsc ×3 + eslint + prettier + knip (frontend) · vitest · pytest. The pytest lane runs in backend/docker-compose.test.yml — an ephemeral Postgres + the backend tree bind-mounted — so the DB-backed integration tests (the db fixture) actually run; SIFTLODE_TEST_ REQUIRE_DB=1 there turns a would-be silent skip into a hard failure. See docs/development.md.