v0.20.4: the song that wasn't there

trav couldn't play the first track of his playlist. Shuffle off gave him song
two; shuffle on gave him a random one. The player was right both times:
library.json named a song whose file was not on the device, and skipping an
unplayable file advances one slot. Tapping any song that *is* there plays
exactly that song, shuffle or not.

The file was missing because a gvfs-MTP mount can hold a phantom directory --
one it lists happily while the device has no such folder. Every write into it
fails EIO, and mkdir(exist_ok=True) sees the phantom and does nothing, so it
never heals; only remounting clears it. That folder was new because Round 52's
retag moved the file under a new artist.

So a copy that raises OSError now costs that song, not the sync, and the song
is left out of the m3u and library.json. Aborting cost 2,400 songs for one
folder; counting it present anyway put a song in the manifest that isn't on
the device, which is the bug you could hear. The names come back in the
summary and a dialog rather than vanishing.

Planning is a worker now. plan_andtunes_sync is pure and writes nothing, but
it walks every file on the device, and over MTP that is thousands of round
trips -- on the GUI thread it froze the window and GNOME offered to kill
LinTunes, which is how a sync got force-quit halfway through.

And the sync stopped going quiet at the end. "Album art 501/501" is emitted
before the last album, and then _write_index, _ship_buttons and
_prune_empty_dirs ran silently: 501 exists() stats over MTP, ~840 KB of
writes and a full tree walk, with the progress line frozen. They report now,
and _write_index reads Art/ in one listing instead of a stat per album.

andTunes 0.2.2: the wheel scrolls the other way in lists, and smoothly --
a detent adds to a pixel debt that a Choreographer callback pays off a
fraction per frame, so one detent eases to a stop and a fast spin blends into
one movement instead of teleporting a row at a time. Volume is unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SKXUgsBBwe3qaHEjeV8ubP

CLAUDE.md

@@ -347,6 +347,21 @@ persistence) → GUI (Qt widgets that read the manager and connect to its signal
   device diff, which had been re-copying every such file over MTP every sync.
   `plan.stale` still carries the device's own spelling — that is what
   `_delete_stale` unlinks by.
+  **A gvfs-MTP mount can hold a *phantom* directory** — one it lists happily
+  while the device has no such folder — and every write into it fails `EIO`
+  forever, because `mkdir(exist_ok=True)` sees the phantom and does nothing.
+  Only remounting clears it (`gio mount -u mtp://…` then `gio mount`). Two
+  rules came out of it (Round 55): a copy that raises `OSError` costs **that
+  song**, not the sync (it lands in the `unwritable` summary list), and the
+  song is then **left out of the m3u and `library.json`** — a manifest naming
+  a file that isn't there is worse than a short one, because the app skips to
+  the next track and the user sees the wrong song play. **Planning is a worker**
+  too (`AndTunesPlanWorker`): `plan_andtunes_sync` is pure, but it walks every
+  file on the device, and over MTP that froze the window long enough for GNOME
+  to offer to kill LinTunes mid-sync. Anything after the last album
+  (`_write_index`, buttons, pruning) must keep emitting progress — it was
+  minutes of silence with the line stuck on `Album art 501/501`, and
+  `_write_index` reads `Art/` in **one listing**, never a stat per album.
   Since Round 50 the app exists: `andtunes/app/` is plain Java against the
   Android framework, built by `andtunes/build.py` (aapt2 → javac → R8 →
   zipalign → apksigner) — **no Gradle, no Kotlin**, because platform 33 +

andtunes/TASKS.md

@@ -11,7 +11,10 @@ Legend: `[ ]` todo · `[~]` in progress · `[x]` done.
 `Library.group()` keyed albums case-folded but artists raw-case, so one artist
 spelled two ways on one album ("RJD2" / "Rjd2") took the whole library down
 with `Couldn't read library.json`. Both maps fold case now, and `Artist` has a
-`key` the way `Album` always did.** What's left is the *Parked* list, pulled in
+`key` the way `Album` always did. 0.2.2 (round 55, 2026-09-14) reversed the
+wheel in lists and made it scroll smoothly (`WheelScroll` — a pixel debt paid
+off per frame, not a row per detent); volume on the other screens is
+unchanged.** What's left is the *Parked* list, pulled in
 as trav finds he needs it. Built with
 `python3 andtunes/build.py` — plain Java, no Gradle, nothing downloaded (see
 `README.md`, *Toolchain*). Phases are andTunes' own; which LinTunes round

andtunes/app/src/main/java/me/teafry/andtunes/ListActivity.java

@@ -52,6 +52,7 @@ public class ListActivity extends BaseActivity {
     private String mode, id;
     private TextView titleBar;
     private ListView list;
+    private WheelScroll wheel;
     private EditText searchBox;
     private final RowAdapter adapter = new RowAdapter();
     private final ArrayList<Row> rows = new ArrayList<>();
@@ -84,6 +85,7 @@ public class ListActivity extends BaseActivity {
         list.setBackgroundColor(Ui.WHITE);
         list.setAdapter(adapter);
         list.setOnItemClickListener((parent, view, position, rowId) -> onRow(rows.get(position)));
+        wheel = new WheelScroll(list);
         column.addView(list, new LinearLayout.LayoutParams(
                 ViewGroup.LayoutParams.MATCH_PARENT, 0, 1f));
 
@@ -95,6 +97,7 @@ public class ListActivity extends BaseActivity {
 
     @Override protected void onDestroy() {
         Library.forget(onLoaded);
+        wheel.stop();
         super.onDestroy();
     }
 
@@ -103,8 +106,9 @@ public class ListActivity extends BaseActivity {
         adapter.notifyDataSetChanged();   // re-mark the playing row
     }
 
+    /** Wheel up moves the list down, the way pushing the page up does. */
     @Override protected void onWheel(int dir) {
-        list.scrollListBy(-dir * Ui.dp(this, Ui.ROW_DP));
+        wheel.push(dir * Ui.dp(this, WheelScroll.STEP_DP));
     }
 
     private String defaultTitle() {

andtunes/app/src/main/java/me/teafry/andtunes/WheelScroll.java

@@ -0,0 +1,68 @@
+package me.teafry.andtunes;
+
+import android.view.Choreographer;
+import android.widget.ListView;
+
+/**
+ * Smooth scrolling for the R1's wheel.
+ *
+ * <p>The wheel arrives as discrete detents, and moving a whole row per detent
+ * reads as a teleport — the list jumps a track at a time instead of gliding
+ * the way a finger drag does. So a detent doesn't scroll: it adds to a pixel
+ * <em>debt</em>, and a Choreographer callback pays a fraction of that debt off
+ * every frame. One detent eases to a stop; a fast spin piles debt up faster
+ * than it drains and becomes one continuous movement.
+ *
+ * <p>Frame-driven rather than animated per detent, because a new detent has to
+ * blend into the motion already underway — restarting an animation each time
+ * is what makes wheel scrolling stutter.
+ */
+final class WheelScroll implements Choreographer.FrameCallback {
+    /** Fraction of the outstanding debt paid per frame: the easing curve. */
+    private static final float FRICTION = 0.28f;
+    /** Below this the remainder is paid in one go rather than halved forever. */
+    private static final float SETTLE_PX = 1.5f;
+    /** How far one detent travels. Deliberately not a row height. */
+    static final int STEP_DP = 52;
+
+    private final ListView list;
+    private float debt;
+    private boolean running;
+
+    WheelScroll(ListView list) {
+        this.list = list;
+    }
+
+    /** One detent, {@code px} signed pixels in the direction to travel. */
+    void push(float px) {
+        debt += px;
+        if (!running) {
+            running = true;
+            Choreographer.getInstance().postFrameCallback(this);
+        }
+    }
+
+    @Override public void doFrame(long frameTimeNanos) {
+        float step = Math.abs(debt) <= SETTLE_PX ? debt : debt * FRICTION;
+        int px = Math.round(step);
+        if (px != 0) {
+            list.scrollListBy(px);
+            debt -= px;      // what actually moved, so hitting either end ends it
+        } else {
+            debt = 0;
+        }
+        if (Math.abs(debt) >= 0.5f) {
+            Choreographer.getInstance().postFrameCallback(this);
+        } else {
+            debt = 0;
+            running = false;
+        }
+    }
+
+    /** Drop any motion still owed (the screen is going away). */
+    void stop() {
+        debt = 0;
+        running = false;
+        Choreographer.getInstance().removeFrameCallback(this);
+    }
+}

andtunes/build.py

@@ -26,8 +26,8 @@ import sys
 import zipfile
 from pathlib import Path
 
-VERSION_NAME = "0.2.1"
-VERSION_CODE = 3
+VERSION_NAME = "0.2.2"
+VERSION_CODE = 4
 
 PACKAGE = "me.teafry.andtunes"
 MIN_SDK = 26

lintunes/__init__.py

@@ -1,3 +1,3 @@
 """LinTunes — iTunes-style music library manager and player for Linux."""
 
-__version__ = "0.20.3"
+__version__ = "0.20.4"

lintunes/android/andTunes.json

@@ -1 +1 @@
-{"version_name": "0.2.1", "version_code": 3}
+{"version_name": "0.2.2", "version_code": 4}

lintunes/andtunes/sync.py

@@ -20,6 +20,7 @@ feeds Auxio, and it stays until andTunes can actually play a song.
 
 import json
 import os
+import shutil
 import threading
 from dataclasses import dataclass, field
 from importlib import resources
@@ -34,8 +35,8 @@ from . import art as art_mod
 from . import layout
 from . import plays as plays_mod
 from .layout import (
-    BUTTONS_DIR, MANIFEST_NAME, PRESERVED_DIRS, album_key, art_relpath,
-    assert_inside, media_relpath, playlist_relpath,
+    ART_DIR, BUTTONS_DIR, MANIFEST_NAME, PRESERVED_DIRS, album_key,
+    art_relpath, assert_inside, media_relpath, playlist_relpath,
 )
 from .manifest import build_manifest
 
@@ -284,6 +285,57 @@ class _Cancelled(Exception):
     """Internal: unwinds _run when cancel() was requested."""
 
 
+class AndTunesPlanWorker(QObject):
+    """`plan_andtunes_sync` on a daemon thread, because planning reads MTP.
+
+    The planner is pure and writes nothing, but it walks every file on the
+    device, and over gvfs-MTP that is thousands of round trips — several
+    seconds on trav's 2,400-song library. On the GUI thread that is a frozen
+    window, and GNOME offers to kill the app: "lintunes is not responding" is
+    how a sync got force-quit halfway through. `disk_usage` rides along
+    because it is one more MTP call the caller needed before deciding.
+    """
+
+    planned = pyqtSignal(object, object)   # AndTunesPlan, free bytes
+    failed = pyqtSignal(str)
+
+    def __init__(self, playlists, tracks, root, device, *,
+                 copy_art=True, data_dir=None, parent=None):
+        super().__init__(parent)
+        self._args = (playlists, tracks, root, device)
+        self._copy_art = copy_art
+        self._data_dir = data_dir
+        self._busy = False
+
+    def busy(self) -> bool:
+        return self._busy
+
+    def start(self):
+        if self._busy:
+            return
+        self._busy = True
+        threading.Thread(target=self._run_guarded, daemon=True).start()
+
+    def _run_guarded(self):
+        try:
+            self._run()
+        finally:
+            self._busy = False
+
+    def _run(self):
+        playlists, tracks, root, device = self._args
+        try:
+            plan = plan_andtunes_sync(playlists, tracks, root, device,
+                                      copy_art=self._copy_art,
+                                      data_dir=self._data_dir)
+            free = shutil.disk_usage(device.root).free if device else 0
+        except OSError as e:
+            name = device.name if device else "device"
+            self.failed.emit(f"Couldn't read the {name}: {e}")
+            return
+        self.planned.emit(plan, free)
+
+
 class AndTunesSyncWorker(QObject):
     """Runs an AndTunesPlan on a daemon thread, reporting through signals.
 
@@ -343,6 +395,7 @@ class AndTunesSyncWorker(QObject):
         self._done = 0
         self._plays = 0          # tracks whose play counts came back
         self._unconverted = 0    # conversions ffmpeg couldn't do
+        self._unwritable: list[tuple[str, str]] = []   # (song, why) per refusal
 
         try:
             self._check_cancel()
@@ -369,6 +422,7 @@ class AndTunesSyncWorker(QObject):
                 "plays": self._plays,
                 "refused": len(plan.refused),
                 "unconverted": self._unconverted,
+                "unwritable": list(self._unwritable),
             })
         except _Cancelled:
             self._drop_partial()
@@ -481,19 +535,36 @@ class AndTunesSyncWorker(QObject):
                 self._emit(label)
                 continue
             dest = plan.root / item.rel
-            dest.parent.mkdir(parents=True, exist_ok=True)
-            self._dest = dest
-            # Manual chunked copy: byte-accurate progress, and no copystat
-            # (gvfs-MTP rejects it).
-            with fsrc, open(dest, "wb") as fdst:
-                while True:
-                    chunk = fsrc.read(CHUNK)
-                    if not chunk:
-                        break
-                    fdst.write(chunk)
-                    self._done += len(chunk)
-                    self._emit(label)
-                    self._check_cancel()
+            # One song the device won't take is one song, not the sync. A
+            # gvfs-MTP mount can hold a *phantom* directory — one it lists but
+            # the device doesn't have — and every write into it fails EIO
+            # forever, since mkdir(exist_ok=True) sees the phantom and does
+            # nothing. Aborting here cost trav 2,400 songs for one folder; and
+            # counting the track present anyway (the older sin) put a song in
+            # library.json that isn't on the device, which the app then skips
+            # mid-playlist. So: report it, and leave it out of the manifest.
+            try:
+                dest.parent.mkdir(parents=True, exist_ok=True)
+                self._dest = dest
+                # Manual chunked copy: byte-accurate progress, and no copystat
+                # (gvfs-MTP rejects it).
+                with fsrc, open(dest, "wb") as fdst:
+                    while True:
+                        chunk = fsrc.read(CHUNK)
+                        if not chunk:
+                            break
+                        fdst.write(chunk)
+                        self._done += len(chunk)
+                        self._emit(label)
+                        self._check_cancel()
+            except OSError as e:
+                fsrc.close()
+                self._drop_partial()
+                self._unwritable.append((track_display(item.track),
+                                         e.strerror or str(e)))
+                self._done += item.size
+                self._emit(label)
+                continue
             self._dest = None
             self._present.add(item.track_id)
 
@@ -535,7 +606,9 @@ class AndTunesSyncWorker(QObject):
         with holes in it.
         """
         plan = self._plan
-        for entry in plan.playlists:
+        total = len(plan.playlists)
+        for i, entry in enumerate(plan.playlists, start=1):
+            self._emit(f"Writing playlist {i}/{total}")
             rows = [row for row, tid in zip(entry.entries, entry.track_ids)
                     if tid in self._present]
             dest = plan.root / entry.rel
@@ -544,9 +617,16 @@ class AndTunesSyncWorker(QObject):
 
         # Which covers are on the device right now, rather than which ones
         # this run wrote — so a cancelled sync still points at art an earlier
-        # sync left behind.
+        # sync left behind. One listing of Art/, not a stat per album: over
+        # MTP that was 500-odd round trips with the progress line frozen on
+        # the last album, which reads exactly like a hang.
+        self._emit("Writing the library")
+        try:
+            on_device = {p.name for p in (plan.root / ART_DIR).iterdir()}
+        except OSError:
+            on_device = set()
         have_art = {key for key in plan.albums
-                    if (plan.root / art_relpath(key)).exists()}
+                    if Path(art_relpath(key)).name in on_device}
         entries = [(item.track, item.rel,
                     art_relpath(k) if (k := album_key(item.track)) in have_art
                     else None)
@@ -568,6 +648,7 @@ class AndTunesSyncWorker(QObject):
         file costs a default image, not the sync.
         """
         plan = self._plan
+        self._emit("Tidying up")
         folder = assert_inside(plan.root, plan.root / BUTTONS_DIR)
         for src in default_buttons():
             dest = folder / src.name

lintunes/gui/main_window.py

@@ -167,6 +167,7 @@ class MainWindow(QMainWindow):
         self._sync_cancel.clicked.connect(self._confirm_cancel_sync)
         self.statusBar().addPermanentWidget(self._sync_cancel)
         self._andtunes_worker = None
+        self._andtunes_planner = None
         self._install_worker = None
         self._sync_device_name = ""
         # Export shares the status-bar progress widgets with device sync —
@@ -465,8 +466,8 @@ class MainWindow(QMainWindow):
 
     def _busy_worker(self):
         """The transfer currently owning the status-bar progress widgets."""
-        for worker in (self._andtunes_worker, self._export_worker,
-                       self._url_worker):
+        for worker in (self._andtunes_planner, self._andtunes_worker,
+                       self._export_worker, self._url_worker):
             if worker is not None and worker.busy():
                 return worker
         return None
@@ -548,17 +549,26 @@ class MainWindow(QMainWindow):
                 "Pick them in Connections → Rabbit Sync Settings…")
             return
 
+        # Planning walks the whole device over MTP — off the GUI thread, or
+        # the window freezes and GNOME offers to kill it mid-sync.
         root = andtunes_layout.root_for(device)
-        try:
-            plan = andtunes_sync.plan_andtunes_sync(
-                playlists, self._manager.library.tracks, root, device,
-                copy_art=bool(self._prefs.device_sync.get("copy_art", True)),
-                data_dir=self._manager.data_dir)
-            free = shutil.disk_usage(device.root).free
-        except OSError as e:
-            QMessageBox.warning(self, "Sync failed",
-                                f"Couldn't read the {device.name}: {e}")
-            return
+        self._andtunes_planner = andtunes_sync.AndTunesPlanWorker(
+            playlists, self._manager.library.tracks, root, device,
+            copy_art=bool(self._prefs.device_sync.get("copy_art", True)),
+            data_dir=self._manager.data_dir, parent=self)
+        self._andtunes_planner.planned.connect(self._on_andtunes_planned)
+        self._andtunes_planner.failed.connect(self._on_sync_failed)
+        self._sync_device_name = device.name
+        self._sync_label.setText(f"Checking the {device.name}")
+        self._sync_progress.setRange(0, 0)     # busy bar: no total to show yet
+        self._sync_label.show()
+        self._sync_progress.show()
+        self._andtunes_planner.start()
+
+    def _on_andtunes_planned(self, plan, free):
+        device = plan.device
+        playlists = plan.playlists
+        self._hide_sync_widgets()
         if plan.needs_ffmpeg and not exporter.web_support.ffmpeg_available():
             conversions = plan.conversions
             names = "\n".join(f"  • {device_sync.track_display(i.track)}"
@@ -618,12 +628,29 @@ class MainWindow(QMainWindow):
             msg += f", {summary['refused']} left out (can't play there)"
         if summary.get("unconverted"):
             msg += f", {summary['unconverted']} couldn't be converted"
+        unwritable = summary.get("unwritable") or []
+        if unwritable:
+            msg += f", {len(unwritable)} the device wouldn't take"
         if summary.get("plays"):
             msg += f"; play counts back for {summary['plays']} song(s)"
             # The journal landed in the data dir; fold it in now rather than
             # waiting for the file watcher.
             self._manager.reload_from_disk()
         self.statusBar().showMessage(msg, 10000)
+        if unwritable:
+            # Worth a dialog: these songs are *not* in the library the app
+            # reads, so they'd otherwise just be quietly absent from the
+            # playlist. A stale gvfs mount is the usual cause.
+            names = "\n".join(f"  • {name} — {why}" for name, why in unwritable[:8])
+            more = (f"\n  … and {len(unwritable) - 8} more"
+                    if len(unwritable) > 8 else "")
+            QMessageBox.warning(
+                self, "Some songs wouldn't copy",
+                f"The {summary['device']} refused "
+                f"{len(unwritable)} song(s):\n\n{names}{more}\n\n"
+                "They've been left out of the library on the device, so the "
+                "app won't list a song it can't play. Unplugging the "
+                "device and plugging it back in usually clears this.")
 
     # ---- connections: install the andTunes app ----
 

tasks-done.md

@@ -1,5 +1,42 @@
 ## Done
 
+### Round 55 (2026-09-14) — the song that wasn't there (v0.20.4, andTunes 0.2.2)
+
+trav couldn't play the first track of his playlist: shuffle off gave him song
+2, shuffle on gave him a random one. The player was right both times —
+`library.json` named a song whose file was not on the device, and skipping an
+unplayable file advances one slot. Verified on the Rabbit: tapping any song
+that *is* there plays exactly that song, shuffle or not.
+
+- [x] **The phantom directory.** `Media/Dionne Farris/` existed as far as gvfs
+      was concerned — it would list the album inside it — and did not exist at
+      all per `adb`. Every write into it failed `EIO`, and
+      `mkdir(exist_ok=True)` saw the phantom and did nothing, so it could never
+      heal while the mount lived. Freshly made folders worked fine, so it was
+      stale cache, not a broken mount. Only remounting clears it. That folder
+      was new because Round 52's retag moved the file under a new artist.
+- [x] **A refused copy costs that song, not the sync**, and the song is left
+      out of the m3u and `library.json`. Aborting cost 2,400 songs for one
+      folder; counting it present anyway put a song in the manifest that isn't
+      on the device, which is what trav was hearing. The names come back in
+      the summary and a dialog, so it is never silent.
+- [x] **Planning is a worker** (`AndTunesPlanWorker`). It is pure and writes
+      nothing, but it walks every file on the device, and over MTP that is
+      thousands of round trips — on the GUI thread it froze the window and
+      GNOME offered to kill LinTunes, which is how a sync got force-quit
+      halfway. `disk_usage` rides along, being one more MTP call.
+- [x] **The tail of the sync says what it's doing.** "Album art 501/501" is
+      emitted *before* the last album, and then `_write_index`,
+      `_ship_buttons` and `_prune_empty_dirs` ran silently — 501 `exists()`
+      stats over MTP, ~840 KB of writes and a full tree walk with the progress
+      line frozen. They report now, and `_write_index` reads `Art/` in one
+      listing instead of a stat per album.
+- [x] **The wheel scrolls smoothly, and the other way** (`WheelScroll`). A
+      detent adds to a pixel debt that a Choreographer callback pays off a
+      fraction per frame, so one detent eases to a stop and a fast spin blends
+      into one movement instead of teleporting a row at a time. Direction
+      flipped in lists only; volume on the other screens is unchanged.
+
 ### Round 54 (2026-09-14) — one artist spelled two ways (v0.20.3, andTunes 0.2.1)
 
 trav synced to the Rabbit, the sync reported success, and andTunes answered

tests/test_round55.py

@@ -0,0 +1,186 @@
+"""Round 55: a song the device wouldn't take, and a window that stayed alive.
+
+trav's Rabbit played the wrong song whenever he tapped the first track of his
+playlist — shuffle off gave him song 2, shuffle on gave him a random one. The
+player was right both times: `library.json` listed a song whose file was not
+on the device, and skipping an unplayable file advances one slot.
+
+The file was missing because a gvfs-MTP mount can hold a **phantom directory**
+— one it lists but the device doesn't have. Every write into it fails EIO, and
+`mkdir(exist_ok=True)` sees the phantom and does nothing, so it never heals.
+Two things were wrong with how sync met that: it aborted the whole run, and
+(worse, when it didn't) the track still went into the manifest.
+
+What's pinned:
+
+* a copy that raises OSError costs **that song**, not the sync, and the song
+  is left out of the m3u and `library.json` — the app can only list what it
+  can play — and comes back in the summary so it isn't silent;
+* planning is a **worker**, because it walks every file on the device and over
+  MTP that froze the window long enough for GNOME to offer to kill LinTunes;
+* the phases after the last album (`_write_index`, buttons, pruning) **say so**
+  — they were minutes of silence with the progress line stuck on the last
+  album, which reads exactly like a hang.
+"""
+
+import json
+
+import pytest
+
+from lintunes.andtunes.sync import (
+    AndTunesPlanWorker, AndTunesSyncWorker, plan_andtunes_sync,
+)
+from lintunes.models import Track
+from lintunes.models.playlist import Playlist, PlaylistType
+
+
+@pytest.fixture(autouse=True)
+def _private_cache(tmp_path, monkeypatch):
+    monkeypatch.setenv("XDG_CACHE_HOME", str(tmp_path / "cache"))
+
+
+DATA = b"x" * 64
+
+
+def _track(tid, name, artist="Band", album="Record", *, tmp_path):
+    path = tmp_path / "local" / f"{tid}.mp3"
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_bytes(DATA)
+    return Track(track_id=tid, name=name, artist=artist, album=album,
+                 location=str(path), total_time=60_000, kind="MPEG audio file")
+
+
+def _playlist(*tids):
+    return Playlist(name="Mix", persistent_id="AAAA0001",
+                    playlist_type=PlaylistType.REGULAR, track_ids=list(tids))
+
+
+def _root(tmp_path):
+    return tmp_path / "device" / "Music" / "andTunes"
+
+
+def _run(plan):
+    worker = AndTunesSyncWorker(plan)
+    out = {"labels": []}
+    worker.finished.connect(lambda s: out.setdefault("finished", s))
+    worker.failed.connect(lambda m: out.setdefault("failed", m))
+    worker.progress.connect(lambda done, total, label: out["labels"].append(label))
+    worker._run()
+    return out
+
+
+def _manifest(root):
+    return json.loads((root / "library.json").read_text(encoding="utf-8"))
+
+
+def _wedge(monkeypatch, bad_name: str):
+    """Make open(..., 'wb') raise EIO for one destination, like a phantom dir."""
+    real = open
+
+    def fake(file, mode="r", *a, **kw):
+        if "w" in str(mode) and str(file).endswith(bad_name):
+            raise OSError(5, "Input/output error", str(file))
+        return real(file, mode, *a, **kw)
+
+    monkeypatch.setattr("builtins.open", fake)
+
+
+# ---- one song the device refuses ----
+
+def test_a_refused_copy_costs_that_song_not_the_sync(tmp_path, monkeypatch):
+    tracks = {
+        1: _track(1, "Wanted", tmp_path=tmp_path),
+        2: _track(2, "Refused", tmp_path=tmp_path),
+        3: _track(3, "Also Wanted", tmp_path=tmp_path),
+    }
+    plan = plan_andtunes_sync([_playlist(1, 2, 3)], tracks, _root(tmp_path))
+    _wedge(monkeypatch, "Refused.mp3")
+
+    out = _run(plan)
+
+    assert "failed" not in out, out.get("failed")
+    summary = out["finished"]
+    assert summary["tracks"] == 2
+    assert [name for name, _why in summary["unwritable"]] == ["Band - Refused"]
+    assert "Input/output error" in summary["unwritable"][0][1]
+
+
+def test_a_refused_song_is_left_out_of_the_library_the_app_reads(
+        tmp_path, monkeypatch):
+    """The whole point: the app must never list a song it can't play."""
+    tracks = {
+        1: _track(1, "Wanted", tmp_path=tmp_path),
+        2: _track(2, "Refused", tmp_path=tmp_path),
+    }
+    root = _root(tmp_path)
+    plan = plan_andtunes_sync([_playlist(1, 2)], tracks, root)
+    _wedge(monkeypatch, "Refused.mp3")
+
+    _run(plan)
+
+    manifest = _manifest(root)
+    assert [t["id"] for t in manifest["tracks"]] == [1]
+    assert manifest["playlists"][0]["tracks"] == [1]
+    m3u = (root / "Playlists" / "Mix.m3u").read_text(encoding="utf-8")
+    assert "Refused" not in m3u
+    assert not (root / "Media/Band/Record/Refused.mp3").exists()
+
+
+def test_no_refusals_means_no_noise_in_the_summary(tmp_path):
+    tracks = {1: _track(1, "Fine", tmp_path=tmp_path)}
+    plan = plan_andtunes_sync([_playlist(1)], tracks, _root(tmp_path))
+
+    summary = _run(plan)["finished"]
+
+    assert summary["unwritable"] == []
+    assert summary["tracks"] == 1
+
+
+# ---- the tail of the sync says what it's doing ----
+
+def test_the_phases_after_the_art_report_progress(tmp_path):
+    tracks = {1: _track(1, "Fine", tmp_path=tmp_path)}
+    plan = plan_andtunes_sync([_playlist(1)], tracks, _root(tmp_path))
+
+    labels = _run(plan)["labels"]
+
+    assert any(l.startswith("Writing playlist") for l in labels), labels
+    assert "Writing the library" in labels, labels
+    assert "Tidying up" in labels, labels
+    # And the index phase is the *last* thing said, not a stale album count.
+    assert labels[-1] == "Tidying up"
+
+
+# ---- planning is a worker ----
+
+def test_planning_runs_off_the_gui_thread_and_reports_a_plan(tmp_path):
+    tracks = {1: _track(1, "Fine", tmp_path=tmp_path)}
+    worker = AndTunesPlanWorker(
+        [_playlist(1)], tracks, _root(tmp_path), None, copy_art=False)
+    got = {}
+    worker.planned.connect(lambda plan, free: got.update(plan=plan, free=free))
+    worker.failed.connect(lambda m: got.update(failed=m))
+
+    worker._run()
+
+    assert "failed" not in got, got.get("failed")
+    assert [i.track_id for i in got["plan"].items] == [1]
+    assert got["free"] == 0          # no device, so nothing to measure
+
+
+def test_a_device_that_goes_away_while_planning_is_reported_not_raised(
+        tmp_path, monkeypatch):
+    tracks = {1: _track(1, "Fine", tmp_path=tmp_path)}
+    monkeypatch.setattr(
+        "lintunes.andtunes.sync.plan_andtunes_sync",
+        lambda *a, **kw: (_ for _ in ()).throw(OSError("device went away")))
+    worker = AndTunesPlanWorker(
+        [_playlist(1)], tracks, _root(tmp_path), None, copy_art=False)
+    got = {}
+    worker.planned.connect(lambda plan, free: got.update(plan=plan))
+    worker.failed.connect(lambda m: got.update(failed=m))
+
+    worker._run()
+
+    assert "plan" not in got
+    assert "device went away" in got["failed"]