Krzysztof kuhy Rudnicki
fe28c8a395
A Duration is an absolute span, so stepping a local DateTime by
Duration(days: 1) moves 23 or 25 hours across a DST boundary and lands on
the wrong wall-clock day. Under Europe/Warsaw, spring-forward 2026-03-29:
lastCompleteDay(2026-03-30) -> 2026-03-28 23:00, the day before
yesterday, not yesterday
weeksAgo: 1 from 2026-04-01 -> 2026-03-24 23:00, a Tuesday, so the
wrong ISO week entirely
a 03-27..03-31 period -> emits four day keys, silently dropping
2026-03-31
The Python half computes all three correctly, because timedelta on a date
has no clock to drift against. So for about two weeks a year the phone and
the PC would report different averages for the same log -- exactly the kind
of device-local divergence the shared-source-of-truth rule exists to stop.
Passing out-of-range components to DateTime's constructor normalizes on the
calendar (day 0 is the previous month's last day), which is what timedelta
already does. The same fix goes to day_status_service's streak walker: it
had the identical pattern and predates this feature, so a streak that
spanned the clock change could break when it should have held.
None of the existing tests could see any of this -- every fixture date sits
in a DST-free span -- so the regression tests use dates that straddle
2026-03-29 and assert on the calendar day rather than the DateTime, which
keeps them meaningful whatever zone the runner is in. Verified they fail
against the old arithmetic before fixing it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DjJqpcEsaV5WRhPXyxCThd
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| .. | ||
| .agents/skills | ||
| android | ||
| assets/icon | ||
| bin | ||
| desktop | ||
| lib | ||
| test | ||
| web | ||
| .gitignore | ||
| .metadata | ||
| analysis_options.yaml | ||
| install_arch.sh | ||
| pubspec.lock | ||
| pubspec.yaml | ||
| README.md | ||
| run.sh | ||
| skills-lock.json | ||
diet_guard_app
Companion app for diet_guard: log meals on the phone, and on the Linux
desktop, sharing one food log through GitHub-backed sync.
Two targets, and only two
| Target | What it is |
|---|---|
| Android | a normal Flutter app (flutter build apk) |
| Linux desktop | the Flutter web build, served by a local wrapper and shown in a Chrome --app window |
There is no linux/ directory. Flutter's GTK embedder manages ~20fps at
3840x2160 -- measured on a stock flutter create counter app, so it is the
toolkit rather than this code -- where the same Dart rendered by Chrome
sustains ~144fps (~/todo/docs/desktop-performance-findings.md). Running
flutter create --platforms linux here would silently restore the slow path.
Commands
flutter test # the app's suite
flutter analyze
bash run.sh # build the web bundle and launch the desktop app
bash install_arch.sh # build + install the pacman package and .desktop entry
flutter build apk --release # the phone build
adb install -r build/app/outputs/flutter-apk/app-release.apk
Never adb uninstall or pm clear this package: both wipe the on-device log.
The desktop wrapper
bin/diet_guard_desktop.dart is the other half of the desktop app, because a
browser cannot touch the filesystem. It:
- serves the built web assets from
build/web(or/opt/diet-guard-app/webonce packaged); - keeps an on-disk copy of every document and photo under
~/.local/share/diet-guard-desktop/, which is what makes a wiped Chrome profile recoverable -- for photos it is the only copy, since they never sync; - holds the GitHub token (
~/.config/diet_guard_app/sync_token, falling back to the PC gate's~/.config/diet_guard/sync_token) and proxiesapi.github.complus the device flow, whose endpoints send no CORS headers and so cannot be called from a page at all.
The port (8732) and the Chrome --user-data-dir must stay fixed.
IndexedDB is keyed by origin and lives inside that profile, so changing either
looks to the app like a device with no history.
Platform seams
dart:io does not fail a web compile; it becomes a stub that throws at
runtime, so the symptom of a missed seam is a blank white window rather than a
build error. Every platform edge is a conditional export -- document_store*,
blob_store*, background_tasks*, notification_backend*, token_vault*,
github_client_factory*, attached_image*. Branch on kIsWeb before any
Platform.is…, which itself throws on web.
What the desktop genuinely loses, by design rather than omission:
- Background reminders. A browser runs nothing once its window is closed,
so the due-slot check runs in-page every 5 minutes while the window is open.
On the PC the real backstop is
diet-guard-gate.timer, which locks the screen. - Camera capture. The browser picker is a file input.
- Photo sharing between devices -- unchanged:
imagePathwas always stripped before push.
Sync identity
Three devices push under diet-guard-sync/devices/: pc (the Python gate),
phone, and desktop. Each must keep its own id -- two devices sharing one
would overwrite each other's pushed log on every tick.