Validate every Aria2 mirror URI, keep metadata cleanup errors truthful, and serialize media registration with lifecycle cancellation so abandoned tombstones cannot accumulate.
Audit Assignment 06 lifecycle paths and preserve truthful state across ambiguous Aria2 resume failures. Clean up partial startup listener registration and prevent stale resume workers from leaking or releasing current permits.
Serialize queue controls, make multi-item moves atomic, await stale enqueue cleanup, and guard late media and progress events. Add deterministic table sorting and regression coverage for worst-case lifecycle races.
Update yt-dlp to 2026.07.04 and refresh the bundled macOS runtime plus engine locks.
Route every non-media download through aria2 by removing the native HTTP fallback path, native GID handling, and the old direct-download harness.
Retry transient aria2 startup/RPC failures before failing, then show the real last error in the download row and Properties modal so Windows failures are diagnosable instead of silent.
Refresh docs and tests around the aria2-only file-download contract, and advance the Firefox extension submodule to its published wording cleanup.
Treat max_tries as the configured retry count instead of total attempts across native, media, aria2, and fallback paths.
Route queue slot acquisition through retirement-aware permit handling so shrinking concurrency does not dispatch new work while active transfers still meet the smaller limit.
Update retry-budget and queue-manager tests to cover the corrected attempt counts and paused aria2 resume behavior.
Disabled implicit system/environment variable proxy fallbacks in reqwest, yt-dlp, and aria2c when no proxy is explicitly provided. Updated useDownloadStore to strictly return 'none' when 'none' is selected or when 'system' proxy is empty, matching IDM/FDM behavior and ignoring http_proxy environment variables.
- launch Firefox handoffs through authenticated reconnect
- preserve usable drafts when metadata lookup fails
- reject stale metadata results and retry failed rows only
- Add backendRegisteredIds and backendDispatchPromises for single dispatch enforcement
- Add detach_download_for_reconfigure to safely modify properties of active downloads
- Add applyProperties logic handling completed, failed, paused, and active queues
- Add extractValidDownloadUrls and fix multi-url paste handling
- Setup vitest and add useDownloadStore unit tests for backend registration lifecycle
Transient network drops and Wi-Fi timeouts no longer promote a download
straight to a hard Failed state. A shared retry engine classifies the
error, emits a transient `Retrying` state, and runs a 3-strike
exponential backoff (2s / 5s / 10s) while preserving the active download
allocation (semaphore permit / worker slot). Resumability primitives are
reused on every retry so no downloaded bytes are discarded.
Engine core (src-tauri/src/retry.rs, new):
- BACKOFF_SCHEDULE = [2s, 5s, 10s], MAX_RETRIES = 3
- backoff_for(strike): schedule index with graceful clamp beyond range
- is_transient_network_error(msg): string classifier covering reqwest,
yt-dlp, and aria2c phrasing; permanent conditions (HTTP 401/403/404/
410/451, not-found, permission denied, out-of-disk) checked first so
they always fail fast
- backoff_and_emit / backoff_and_emit_cancel: cancel-safe sleep helpers
driving a Retrying state emit before each delay
- 9 unit tests covering schedule math, clamping, transient vs permanent
classification, and permanent-wins-over-transient precedence
State model (src-tauri/src/ipc.rs):
- DownloadStatus::Retrying variant (serialized "retrying")
- DownloadStateEvent::retrying(id, reason) constructor
- Regenerated TypeScript binding: src/bindings/DownloadStatus.ts
Native reqwest backend (src-tauri/src/download.rs):
- DownloadEvent::Retrying variant (headless mirror)
- CoordinatorEventSink::emit_retrying() drives the production
download-state channel with status "retrying"
- download_file retry core rewritten: transient -> emit_retrying ->
backoff_for sleep inside a control_rx select (pause/cancel honored
mid-backoff) -> re-issue Range header; permanent errors or strike
exhaustion advance to the next URL then hard Failed
yt-dlp media backend (src-tauri/src/lib.rs):
- child spawn+stream loop wrapped in a 3-strike re-spawn loop; stderr
tail classified and, if transient, the process is re-spawned after
backoff (--continue resumes); --retry-wait=2 added to aria2c downloader
aria2c backend (src-tauri/src/queue.rs):
- retry-wait=2 option so aria2's internal retries are not rapid-fire
- handle_aria2_download_error: intercepts transient onDownloadError,
backs off, re-issues addUri, and rotates the stale gid -> id mapping
via rotate_aria2_gid (fresh addUri mints a new gid; not rotating would
detach subsequent WS events and leak the semaphore permit permanently)
- aria2_payloads / aria2_retry_strikes tracking with cleanup on terminal
outcomes
Verification: cargo build clean; cargo test --lib 37 passed / 0 failed.