Tizian 「ティツィアーン」
5d47efd7c5
The developer's decisions of 10 Nov 2026 on their evening's requests: - ADR 0042: every app holds its sync back on a metered connection, as the OS says, and asks in a quiet banner (Sync now, Without files, Not now); an answer holds until the connection changes; Settings › Sync chooses Ask, Without files or Everything. - ADR 0043: Learn's file store moves into halkyon_base, room counted per service; Todo gets sealed attachments in descriptions and comments, any file up to 100 MB, fetched when shown. - ADR 0044: shared spaces in halkyon_base for every app, Learn's studysets first: Owner, Editor and Viewer, keys wrapped to members' key pairs, invites by handle or email, links off at first, the material to publish chosen item by item, and agents as accounts of their own whose changes are suggestions a person accepts. Its open questions come before building, first how rows move between spaces. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
55 lines
3 KiB
Markdown
55 lines
3 KiB
Markdown
# ADR 0042: Sync held back on mobile data
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- **Status:** decided 10 Nov 2026 by the developer: D1 is their own request, D2 to D5
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the agent's recommendations, which they chose. Not built yet.
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- **Builds on:** ADR 0014 (halkyon_app, every app's shell, with its `SyncService`).
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## Context
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Every Halkyon app syncs whenever something changes and on a timer, on whatever network
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the device has. Learn's library holds tens of thousands of rows and hundreds of
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megabytes of PDFs; a first sync, or an import on another device, can take a phone's
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monthly data on the go. The developer asked (10 Nov 2026): *"It should hold back
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everything, asking the user whether one wants to sync. Then, give also the option to
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exclude files, images etc."*
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## Decisions
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- **D1.** On mobile data, every app holds back its sync, rows and files alike, and asks
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first. Built once, in halkyon_app, around its `SyncService`; nothing an app does on
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the device waits on it (local-first as before: what is written is kept and sent
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later).
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- **D2.** *Mobile data* is a **metered** connection as the operating system says: on
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Android its `NET_CAPABILITY_NOT_METERED` missing, which takes in cellular and also a
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phone's hotspot or a Wi-Fi network marked metered; read by a few lines of Kotlin in
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halkyon_app's plugin code (`connectivity_plus` tells only the kind of network, which
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misses the hotspot). iOS: `NWPath.isExpensive`, once the iOS builds ship. Desktops
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are never metered.
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- **D3.** It asks with a **quiet banner** above the lists, never a dialog: *On mobile
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data · 12 changes waiting* with *Sync now*, *Without files* and *Not now*. *Not now*
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hides it until something new waits. Pulling a list down to sync is an explicit ask
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too, and syncs as *Sync now* would.
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- **D4.** An answer **holds until the connection changes**: while the device stays on
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this metered network; asked again after Wi-Fi came and went, or when the app starts
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again on mobile data.
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- **D5.** Settings › Sync has *On mobile data*: **Ask** (the default), **Without files**,
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**Everything**. No *Never*: *Not now* holds back already. A device setting (as the
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look), not synced: a tablet on Wi-Fi alone and a phone differ.
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## What "without files" means
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Rows sync; files neither go up nor come down. Each app names its files to halkyon_app
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as a queue of its own (Learn's asset uploads and downloads, its PDFs and Jellyfin
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covers; Todo's attachments, ADR 0043; Train's maps' tiles stay as they are, fetched
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when shown), which `SyncService` pauses and resumes. What is waiting shows in Sync's
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card (*3 files waiting for Wi-Fi*).
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## To work out when building
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- Where the banner sits in each app's frame: halkyon_ui's `NavigationFrame` has no
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place for one above every tab yet.
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- The sync engine's stream: whether held back means not opening it at all (the
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recommendation: nothing goes over the network, not even the handshake) or opening it
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and sending nothing.
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- Learn's offline reads (b578fcb9) must not wait on a sync held back: the tests of
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`ContentKeys` and the gateways already run without one.
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