web: restore deletes its snapshot by open identity, not name

Second review pass found the restore marker matched WebFileOpened by
display name: any same-named open finishing while the recovered one
was still queued deleted the only copy. The snapshot key now travels
with the queued file (tagged queue entries), the marker records the
open id assigned at dispatch, and success, failure, and cancel all
match that id. Cancelling an unrelated open no longer clears a
pending restore marker.

Also: the boot scan removes dead index rows (missing or zero-byte
snapshot files) that no other path could discard, and the drop
listener install only latches when the listeners really registered.

(cherry picked from commit c8777a857b)

src/app/mod.rs

@@ -927,11 +927,12 @@ pub(super) struct OpenCADStudio {
     /// prompt still has to offer, one at a time.
     #[cfg(target_arch = "wasm32")]
     web_autosave_pending: Vec<crate::io::web_autosave::WebAutosaveEntry>,
-    /// The snapshot whose recovered open is queued: `(autosave key,
-    /// open name)`. The OPFS copy is the only one, so it is deleted only
-    /// once an open with exactly that name succeeds.
+    /// The snapshot whose recovered open is in flight: `(autosave key,
+    /// open id)`. The OPFS copy is the only one, so it is deleted only
+    /// once the open with exactly that id succeeds — identity, never the
+    /// display name (same-named files share one stored copy on web).
     #[cfg(target_arch = "wasm32")]
-    web_autosave_consumed: Option<(String, String)>,
+    web_autosave_consumed: Option<(String, u64)>,
     /// Autosave keys a web save wanted to remove while a snapshot round was
     /// still writing (the round's late write would resurrect the snapshot
     /// with a fresh mtime); the removes run when the round finishes.
@@ -2260,8 +2261,10 @@ pub enum Message {
     FileDropped(PathBuf),
     /// Web only: a drawing dragged onto the page — the DOM drop listener has
     /// already read the bytes; this opens through the web-picker flow (#344).
+    /// The third field tags an autosave-restore file with its snapshot key so
+    /// the snapshot is deleted only when this exact open succeeds.
     #[cfg(target_arch = "wasm32")]
-    WebFileDropped(String, Vec<u8>),
+    WebFileDropped(String, Vec<u8>, Option<String>),
     /// Web only: Ctrl+V captured by a focused text field, whose iced-internal
     /// paste is inert there — read the async clipboard instead (#346).
     WebFieldPaste,
@@ -2337,7 +2340,7 @@ pub enum Message {
     /// Web: the offered snapshot's bytes are in; queue them for the guarded
     /// open poll. The OPFS copy is consumed only once that open succeeds.
     #[cfg(target_arch = "wasm32")]
-    WebAutosaveBytes(String, Result<Vec<u8>, String>),
+    WebAutosaveBytes(String, String, Result<Vec<u8>, String>),
     /// Web: one autosave round finished for all dirty tabs (serially).
     #[cfg(target_arch = "wasm32")]
     WebAutosaveSnapshotFinished(Result<(), String>),

src/app/update/file.rs

@@ -3684,29 +3684,24 @@ impl OpenCADStudio {
         self.close_active_modal();
         let open_name = crate::io::web_autosave::recovered_name(&entry.name);
         let key = entry.name;
-        // Remember the pair: `web_autosave_opened` deletes the OPFS copy
-        // only when an open with exactly `open_name` succeeds. A failed
-        // read below clears the marker again (`on_web_autosave_bytes`).
-        self.web_autosave_consumed = Some((key.clone(), open_name.clone()));
+        // The snapshot key travels with the bytes: the marker (and the
+        // deletion it authorises) is recorded only when the poll actually
+        // starts this open, keyed by that open's id — never by display name.
+        let read_key = key.clone();
         Task::perform(
-            async move { crate::io::web_autosave::read(&key).await },
-            move |result| Message::WebAutosaveBytes(open_name, result),
+            async move { crate::io::web_autosave::read(&read_key).await },
+            move |result| Message::WebAutosaveBytes(open_name, key, result),
         )
     }
 
     /// The recovered drawing opened: its autosave snapshot — held back until
     /// now — can finally be deleted, and the next queued snapshot can be
-    /// offered. A different name finishing first just means the recovered
-    /// open is still queued behind it; keep waiting.
+    /// offered. The caller already matched the marker to this open's id.
     #[cfg(target_arch = "wasm32")]
     pub(super) fn web_autosave_opened(&mut self, open_name: &str) {
-        let Some((key, recorded)) = self.web_autosave_consumed.clone() else {
+        let Some((key, _)) = self.web_autosave_consumed.take() else {
             return;
         };
-        if recorded != open_name {
-            return;
-        }
-        self.web_autosave_consumed = None;
         self.command_line
             .push_output(crate::tf!("Restored \"{}\" from the autosave copy", open_name).as_ref());
         wasm_bindgen_futures::spawn_local(async move {
@@ -3741,6 +3736,7 @@ impl OpenCADStudio {
     pub(super) fn on_web_autosave_bytes(
         &mut self,
         open_name: String,
+        key: String,
         result: Result<Vec<u8>, String>,
     ) -> Task<Message> {
         match result {
@@ -3749,7 +3745,7 @@ impl OpenCADStudio {
                 // (`web_autosave_opened` / the failure hook), not here — the
                 // poll has not started the open yet, so queueing now would
                 // show the modal before the recovered drawing loads.
-                crate::io::web_drop::enqueue_open(open_name, bytes);
+                crate::io::web_drop::enqueue_restore(open_name, bytes, key);
                 Task::none()
             }
             Err(error) => {
@@ -3757,7 +3753,6 @@ impl OpenCADStudio {
                 // re-offer it this session — it was already taken out of
                 // `web_autosave_pending`, so the cycle cannot loop on it.
                 // It stays discardable on the next boot.
-                self.web_autosave_consumed = None;
                 self.command_line
                     .push_warning(crate::tf!("Autosave copy could not be read: {error}").as_ref());
                 self.queue_next_web_autosave_prompt();

src/app/update/mod.rs

@@ -675,7 +675,13 @@ impl OpenCADStudio {
                     && self.active_modal != Some(super::ModalKind::Recovery)
                 {
                     crate::io::web_drop::take_dropped()
-                        .map(|(name, bytes)| self.update(Message::WebFileDropped(name, bytes)))
+                        .map(|file| {
+                            self.update(Message::WebFileDropped(
+                                file.name,
+                                file.bytes,
+                                file.restore_key,
+                            ))
+                        })
                         .unwrap_or_else(Task::none)
                 } else {
                     Task::none()
@@ -1097,35 +1103,56 @@ impl OpenCADStudio {
             }
 
             Message::OpenCancel => {
+                #[cfg(target_arch = "wasm32")]
+                let cancelled_id = self.opening.as_ref().map(|opening| opening.id);
                 if let Some(p) = self.opening.take() {
                     self.command_line
                         .push_info(crate::tf!("Open cancelled: \"{}\"", p.name).as_ref());
                 }
                 // A cancelled recovered open keeps its snapshot (re-offered
                 // next boot — it is the only copy); the remaining queued
-                // snapshots can still be offered this session.
+                // snapshots can still be offered this session. Match on the
+                // open's id so cancelling an unrelated open leaves a pending
+                // restore marker alone.
                 #[cfg(target_arch = "wasm32")]
-                if self.web_autosave_consumed.take().is_some() {
+                if cancelled_id
+                    .is_some_and(|id| {
+                        self.web_autosave_consumed
+                            .as_ref()
+                            .is_some_and(|(_, recorded)| *recorded == id)
+                    })
+                    && self.web_autosave_consumed.take().is_some()
+                {
                     self.queue_next_web_autosave_prompt();
                 }
                 self.drain_pending_open()
             }
 
             #[cfg(target_arch = "wasm32")]
-            Message::WebFileDropped(name, bytes) => {
+            Message::WebFileDropped(name, bytes, restore_key) => {
                 // Bytes are already in hand (no picker round-trip), so this is
                 // `on_open_file`'s web branch with the real name and size on
                 // the overlay from the start. An open already in flight must
                 // not be clobbered (its bytes are gone once dequeued), so the
-                // pair goes back to the queue for the next poll tick.
+                // entry goes back to the queue for the next poll tick.
                 if self.opening.is_some() {
-                    crate::io::web_drop::enqueue_open(name, bytes);
+                    match restore_key {
+                        Some(key) => {
+                            crate::io::web_drop::enqueue_restore(name, bytes, key)
+                        }
+                        None => crate::io::web_drop::enqueue_open(name, bytes),
+                    }
                     return Task::none();
                 }
                 let state = std::sync::Arc::new(crate::io::OpenProgressState::new(
                     crate::app::OPEN_PHASE_READING,
                 ));
                 let open_id = self.next_open_id();
+                // Identity, not display name: only this exact open may delete
+                // the snapshot the restore came from.
+                if let Some(key) = restore_key {
+                    self.web_autosave_consumed = Some((key, open_id));
+                }
                 self.opening = Some(crate::app::OpenProgress {
                     id: open_id,
                     name: name.clone(),
@@ -1155,7 +1182,7 @@ impl OpenCADStudio {
                 if self
                     .web_autosave_consumed
                     .as_ref()
-                    .is_some_and(|(_, recorded)| *recorded == outcome.name)
+                    .is_some_and(|(_, recorded)| *recorded == open_id)
                 {
                     if outcome.result.is_ok() {
                         self.web_autosave_opened(&outcome.name);
@@ -1285,7 +1312,9 @@ impl OpenCADStudio {
             #[cfg(target_arch = "wasm32")]
             Message::WebAutosaveDiscard => self.on_web_autosave_discard(),
             #[cfg(target_arch = "wasm32")]
-            Message::WebAutosaveBytes(name, result) => self.on_web_autosave_bytes(name, result),
+            Message::WebAutosaveBytes(name, key, result) => {
+                self.on_web_autosave_bytes(name, key, result)
+            }
             #[cfg(target_arch = "wasm32")]
             Message::WebAutosaveSnapshotFinished(result) => self.on_web_autosave_finished(result),