fix(fuse): land a conflict copy in the root when its folder is gone (B150)

docs/BUGS.md

@@ -12,6 +12,26 @@ Conventions:
 
 ---
 
+## B150 — A conflict copy whose folder is gone retries forever
+
+**Status:** Fixed (unverified).
+**Found:** 2026-10-04, by the journal check of the account run on a6f36d5: 33 warnings, one
+every two minutes for the whole run, all "queued write conflicts; keeping a conflict copy" for a
+`write.bin` from an earlier run's B79 case, each followed by `DoesNotExist` from Drive.
+
+**Where:** `Core::keep_as_conflict_copy` in `crates/pdfs-fuse/src/drain.rs`.
+
+**Cause.** A queued write to a file that was trashed or deleted on Drive is kept as a conflict
+copy beside the file. When the file's folder was deleted too, the upload into it failed, the op
+backed off and tried again, with no end. The copy only fell back to the root when the tree had
+forgotten the file, not when Drive had lost its folder.
+
+**Fix.** The copy checks that the folder is still on Drive and not trashed, and lands in the
+location's root otherwise. Sim test `a_queued_write_whose_folder_was_trashed_lands_in_the_root`.
+
+**Left open.** How the B79 case's bytes stayed in `staging/` after the file was deleted, so that
+the next start queued them again ("reconciled orphaned staged writes queued=1"), is not known yet.
+
 ## B149 — `pdfs rename` or `pdfs move` right after a rename through the mount is undone
 
 **Status:** Fixed (unverified).

docs/CHANGELOG.md

@@ -33,6 +33,8 @@ folder by local id too.
   for this release.
 
 ### Fixed
+- **A change to a file deleted elsewhere, together with its folder, no longer retries forever.**
+  The conflict copy that keeps it now lands in the location's root (B150).
 - **`pdfs rename` and `pdfs move` right after a change through the mount are no longer undone.**
   They are queued behind it, and they work on a file that has not reached Drive yet (B149).
 - **A folder kept offline before it reached Drive stays kept offline.** Its pin was lost when the

docs/MILESTONE-3.0.0-STATUS.md

@@ -9,7 +9,7 @@ Tracks `docs/MILESTONE-3.0.0.md`. Update it with every commit that moves a phase
 - **Phase 2**: local ids, inode = local id, one tree for every mount (2.10.0).
 - **Phase 3, first part**: mkdir, create, rename, unlink and rmdir on the mount are recorded
   locally and sent from the queue; `"local_first": false` brings back the old path (5e0f30c).
-- Fixes from the simulation and account runs since then: B141 to B149.
+- Fixes from the simulation and account runs since then: B141 to B150.
 - **Sync issues, first cut** (§6.2): refusals sorted into issues, shown at once in the app,
   tray and CLI; Export button and `pdfs sync export`; `pdfs sync issues`.