Refuse a scan whose root has gone, instead of reporting it empty

FR-PLAT-AND-2, and a silent failure on both platforms. `dr_sync::scan`
stepped over a NotFound or PermissionDenied the way it does for a child
that vanished mid-walk -- correct for a child, wrong for the root, where
it ended the walk, returned Ok with nothing in it, and reported a
successful scan of a library that was no longer there.

A lost root is now its own error. The images under it are marked
Availability::Offline per FR-CAT-9 and no catalog row is deleted;
`library::persist` clears the mark per file as each one is listed again,
so a root that comes back needs no repair step.

Partly satisfied rather than closed, and the gap is worth stating.
The recovery half is real and reachable on Android today, because
`map_status` turns Nextcloud's 403 and 404 into it and Nextcloud is how
a phone actually gets a library in this build. The causes the
requirement names -- revocation, reinstall, a removed card -- are
properties of a persisted tree permission, and there is none: SAF does
not exist here, `SourceRef::Document` is constructed only in test
modules, and `LocalStorage` rejects the variant outright. When SAF
lands it becomes a third producer of this error and nothing above it
changes, which is why the discovery belongs in the connector.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-08-29 23:20:57 +02:00
co-authored by Claude Opus 5
parent 085ab766b3
commit 7418b040da
8 changed files with 478 additions and 38 deletions
+101 -5
View File
@@ -80,7 +80,20 @@ pub enum ScanMessage {
/// amount of string matching on the far side can reliably recover it.
/// Without the flag a dead connection and a bad password produce the same
/// banner, which sends the user to re-enter a credential that was fine.
Failed { message: String, offline: bool },
///
/// `lost_root` is the same idea one step further out, and it is carried
/// separately from `offline` rather than folded into it because the two
/// end differently. An offline library comes back when the network does,
/// with nothing asked of anyone; a library whose root cannot be opened
/// comes back only when someone restores access to it — a share put back
/// on the server, a drive plugged in, and in time a document tree granted
/// again once one can be (FR-PLAT-AND-2). Both show the same grid of what
/// is stored locally, and they must not offer the same explanation.
Failed {
message: String,
offline: bool,
lost_root: bool,
},
}
/// One decoded thumbnail, ready for the grid.
@@ -1166,6 +1179,7 @@ pub fn spawn_scan(
let _ = tx.send(ScanMessage::Failed {
message: e.message,
offline: e.offline,
lost_root: e.lost_root,
});
}
});
@@ -1180,6 +1194,7 @@ pub fn spawn_scan(
struct ScanFailure {
message: String,
offline: bool,
lost_root: bool,
}
impl ScanFailure {
@@ -1189,6 +1204,7 @@ impl ScanFailure {
Self {
message: message.to_string(),
offline: false,
lost_root: false,
}
}
}
@@ -1197,11 +1213,48 @@ impl From<dr_sync::RemoteError> for ScanFailure {
fn from(e: dr_sync::RemoteError) -> Self {
Self {
offline: e.indicates_offline(),
lost_root: e.indicates_lost_root(),
message: e.to_string(),
}
}
}
/// TRACES: FR-PLAT-AND-2 | FR-CAT-9
/// Record that a library can no longer be opened, without losing it.
///
/// Called on the worker, before the failure crosses the channel, because this
/// is where the catalog handle is — and because the marking must be durable
/// whether or not anyone is left to draw a banner. A process killed between
/// the failure and the next launch must still come back knowing what it could
/// not reach.
///
/// Nothing is deleted. Every rating, every edit and every row stays exactly
/// where it was; what changes is that the images now say they are offline, so
/// the grid can show them as held-not-here rather than as ordinary
/// photographs whose thumbnails happen to be failing one at a time.
///
/// A root with no row yet is the first scan of a library that has never
/// succeeded, and there is nothing to mark — the failure alone is the whole
/// story, and the launch screen is where it is told.
fn mark_library_offline(catalog: &Catalog, root: &str) {
let conn = catalog.connection();
let root_id: Option<i64> = conn
.query_row(
"SELECT id FROM roots WHERE label = ?1 AND kind = 'remote'",
[root],
|r| r.get(0),
)
.ok();
let Some(root_id) = root_id else {
log::info!("library {root} has no catalog root yet; nothing to mark offline");
return;
};
match dr_catalog::mark_root_offline(conn, dr_types::RootId(root_id as u64)) {
Ok(()) => log::warn!("library {root} is unreachable; its images are marked offline"),
Err(e) => log::error!("could not mark {root} offline: {e}"),
}
}
fn run_scan(
tx: &Sender<ScanMessage>,
conn: Connection,
@@ -1219,21 +1272,50 @@ fn run_scan(
let rt = crate::net_runtime::build().map_err(ScanFailure::local)?;
rt.block_on(async {
let backend = crate::remote::connect(&conn).map_err(ScanFailure::local)?;
// TRACES: FR-PLAT-AND-2 | FR-CAT-9
// Classified rather than flattened to a local failure, because the
// removed-card case never gets as far as a request: the folder
// connector checks its root when it is constructed, so a library on an
// ejected card fails here and not in the walk. Reported as an ordinary
// error it left the grid showing a healthy library of images that
// could no longer be opened, one silent thumbnail failure at a time.
let backend = match crate::remote::connect(&conn) {
Ok(b) => b,
Err(e) => {
if e.indicates_lost_root() {
mark_library_offline(&catalog, &root);
}
return Err(e.into());
}
};
// Stored folder ETags, so an unchanged subtree is skipped whole. On a
// first run this is empty and the walk is complete; on every run after
// it is what keeps cost proportional to what changed (ARCH §8.4).
let known = load_folder_etags(&catalog, &root);
let result = dr_sync::scan(&*backend, &RemotePath::new(&root), &filter, &known, |p| {
let scanned = dr_sync::scan(&*backend, &RemotePath::new(&root), &filter, &known, |p| {
let _ = tx.send(ScanMessage::Progress {
directories: p.directories_listed,
pruned: p.directories_pruned,
images: p.images_found,
});
})
.await?;
.await;
// TRACES: FR-PLAT-AND-2 | FR-CAT-9
// Written before the failure is reported, not after: the banner is a
// consequence of the catalog state and not the other way round, and a
// process that dies between the two must come back knowing.
let result = match scanned {
Ok(r) => r,
Err(e) => {
if e.indicates_lost_root() {
mark_library_offline(&catalog, &root);
}
return Err(e.into());
}
};
persist(&catalog, &root, &result).map_err(ScanFailure::local)?;
@@ -1326,13 +1408,27 @@ fn persist(
.ok()
});
// TRACES: FR-PLAT-AND-2 | FR-CAT-9
// The `availability` arm is what ends an offline library, and it does
// it one photograph at a time. 3 is `Availability::Offline` and 0 is
// `MetadataOnly`, the same code this statement inserts new rows with —
// so a row that was marked offline when the root became unreachable is
// returned to exactly the state a fresh scan would have given it, and
// a row that was never marked is not touched at all.
//
// Conditional rather than a blanket reset for the same reason
// `dr_catalog::walk` restores per file rather than per root: the only
// thing that may clear "I could not reach this" is having reached it,
// and this statement runs precisely once per file the scan listed.
tx.execute(
"INSERT INTO images(root_id, folder_id, source_ref, format, file_size,
availability, metadata_state, added_at)
VALUES (?1, ?2, ?3, ?4, ?5, 0, 1, ?6)
ON CONFLICT(root_id, source_ref) DO UPDATE SET
file_size = excluded.file_size,
folder_id = excluded.folder_id",
folder_id = excluded.folder_id,
availability = CASE WHEN images.availability = 3
THEN 0 ELSE images.availability END",
rusqlite::params![
root_id,
folder_id,
+86 -12
View File
@@ -270,6 +270,22 @@ pub struct LibraryController {
/// judgement, and carrying the old one over would report a server down
/// that was never contacted.
reachability: RefCell<dr_sync::Reachability>,
/// TRACES: FR-PLAT-AND-2 | FR-CAT-9
/// Why the library folder itself could not be opened, if it could not.
///
/// Beside [`Self::reachability`] rather than inside it, because
/// `dr_sync::Reachability` models *the server*, and it is deliberately
/// unmoved by a refusal — a forbidden file must not report the network as
/// down (see its own tests). A revoked tree grant is a refusal, so folding
/// it in would either break that rule or need an exception carved through
/// it.
///
/// Set only by a scan that failed at the root, and cleared only by one
/// that succeeded. Both states drive the same banner as being offline
/// does, because what the user can do is the same — carry on with what is
/// stored on the device — but the sentence under it is different, and so
/// is what will end it.
root_lost: RefCell<Option<String>>,
/// TRACES: FR-NC-6a
/// Drains the pin downloader. Held so a second pin replaces the timer
/// rather than leaving two draining the same finished channel.
@@ -372,6 +388,7 @@ impl LibraryController {
sidecar_timer: RefCell::new(None),
generation: std::cell::Cell::new(0),
reachability: RefCell::new(dr_sync::Reachability::new()),
root_lost: RefCell::new(None),
outbox_timer: RefCell::new(None),
outbox_maybe_dirty: std::cell::Cell::new(true),
geometry_timer: RefCell::new(None),
@@ -443,10 +460,15 @@ impl LibraryController {
}
}
/// TRACES: FR-CAT-9
/// Whether the app currently believes the server is unreachable.
/// TRACES: FR-CAT-9 | FR-PLAT-AND-2
/// Whether the library cannot be reached, for either of the two reasons.
///
/// One answer rather than two because every caller asks it for the same
/// purpose: to decide whether starting a transfer is worth attempting.
/// A revoked grant fails that question exactly as a dead network does, and
/// a sync started against it would spend its retries proving it.
pub fn is_offline(&self) -> bool {
self.reachability.borrow().is_offline()
self.reachability.borrow().is_offline() || self.root_lost.borrow().is_some()
}
/// Whether the grid is narrowed to locally-stored originals.
@@ -941,6 +963,17 @@ fn drain_scan(
{
log::info!("back online");
}
// TRACES: FR-PLAT-AND-2
// And it is the only evidence that clears a lost root,
// for the same reason: the walk began by listing the
// root, so a scan that finished is a root that opened.
// The rows it marked offline are restored one at a
// time by `library::persist`, as each file is listed
// again — this only stops the banner claiming what is
// no longer true.
if ctl.root_lost.borrow_mut().take().is_some() {
log::info!("library folder is readable again");
}
refresh_offline(&w, ctl);
// An incremental rescan lists almost nothing, so
@@ -995,7 +1028,11 @@ fn drain_scan(
stop(&ctl.scan_timer);
return;
}
ScanMessage::Failed { message, offline } => {
ScanMessage::Failed {
message,
offline,
lost_root,
} => {
log::warn!("scan failed: {message}");
w.set_library_scanning(false);
// Recorded as a failure even where it is only the
@@ -1004,7 +1041,26 @@ fn drain_scan(
// stopped because of it.
job.fail(message.clone());
if offline {
if lost_root {
// TRACES: FR-PLAT-AND-2 | FR-CAT-9
// The library folder itself could not be opened —
// a share withdrawn, an unplugged drive, and in
// time a revoked document-tree grant. The worker
// has already marked every row under this root
// offline and deleted none of them; this is the
// half the user sees.
//
// Tested first because it is also true that the
// library is unreachable, and the generic answer
// would be reached first and be less useful.
*ctl.root_lost.borrow_mut() = Some(message);
refresh_offline(&w, ctl);
// Same reason as the offline arm below: without
// this a launch that began with a revoked grant
// shows an empty grid, which is the one impression
// this whole path exists to avoid.
open_catalog_for_offline(&w, ctl, &catalog_path, &coll_ctl);
} else if offline {
// Not an error state. The catalog from the last
// successful scan is still on disk and still
// accurate for everything already indexed, so the
@@ -1585,17 +1641,35 @@ fn scope_is_pinned(catalog: &Catalog, images: &[dr_types::ImageId]) -> bool {
/// which is what keeps it testable without a display server.
fn refresh_offline(window: &AppWindow, ctl: &Rc<LibraryController>) {
let reach = ctl.reachability.borrow();
let offline = reach.is_offline();
// TRACES: FR-PLAT-AND-2
// A lost root wins over a dead network, and does so even when both are
// true — which is the ordinary case, since the scan that discovered the
// grant was gone was also the last request the app made. Reported the
// other way round the user is told to wait for a connection that is
// working, and the thing that would actually fix it is never mentioned.
let lost = ctl.root_lost.borrow();
let offline = reach.is_offline() || lost.is_some();
window.set_library_offline(offline);
window.set_library_offline_reason(reach.reason().unwrap_or_default().into());
window.set_library_offline_reason(match lost.as_deref() {
Some(why) => why.into(),
None => reach.reason().unwrap_or_default().into(),
});
window.set_library_offline_since(
reach
.offline_for(std::time::Instant::now())
.map(describe_duration)
.unwrap_or_default()
.into(),
// A duration is what a network outage has and a revoked permission
// does not: "for 4 minutes" invites waiting, and waiting is precisely
// what will not help here.
if lost.is_some() {
slint::SharedString::default()
} else {
reach
.offline_for(std::time::Instant::now())
.map(describe_duration)
.unwrap_or_default()
.into()
},
);
drop(lost);
// A stale scan error under an offline banner reports one problem twice.
if offline {