Fix pedalboard refetch / last.json restore race condition

CHANGELOG.md

@@ -4,6 +4,11 @@ Notable user visible changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [v3.3.1] - 2026-08-14
+### Fixed
+- Pedalboards list no longer shows deleted pedalboards after they are removed from MOD-UI
+- Fixed a race condition where Restore would re-write `last.json`, triggering a crash when the pedalboard it refers to does not yet exist when it is re-scanned
+
 ## [v3.3.0] - 2026-08-14
 ### Added
 - Welcome screen on startup

modalapi/modhandler.py

@@ -198,6 +198,7 @@ def __init__(self, audiocard: Audiocard, homedir, data_dir="/home/pistomp/data")
         # Backup
         self.backup_file = "pistomp_backup.zip"
         self.data_dir = data_dir
+        self._restoring = False
 
         # Banks
         self.banks_file = os.path.join(self.data_dir, "banks.json")
@@ -970,6 +971,11 @@ def poll_modui_changes(self):
         # reads next_pedalboard_preset_index this tick. No-op if already drained.
         self.poll_ws_messages()
 
+        # unzip rewrites last.json/banks.json/snapshots.json
+        # don't poll again until we restart the service
+        if self._restoring:
+            return
+
         # Check for pedalboard change via last.json
         if self.last_json_monitor.check_for_change():
             self._is_pedalboard_loading = True
@@ -980,6 +986,15 @@ def poll_modui_changes(self):
 
                 if mod_bundle not in self.pedalboards:
                     self.load_pedalboards()
+                if mod_bundle not in self.pedalboards:
+                    # MOD-UI owns this relationship; if its own list still lacks
+                    # the bundle we have nothing to load and no business picking
+                    # a substitute mid-session. Keep the board we have.
+                    logging.warning("last.json names a pedalboard MOD-UI does not list: %s", mod_bundle)
+                    self._is_pedalboard_loading = False
+                    self.lcd.link_data(self.pedalboard_list, self.current, self.hardware.footswitches)
+                    self.lcd.draw_main_panel()
+                    return
 
                 pb = self.reload_pedalboard(mod_bundle)
                 self.set_current_pedalboard(pb)
@@ -1053,6 +1068,8 @@ def load_pedalboards(self):
             sys.exit()
 
         pbs = json.loads(resp.text)
+        self.pedalboards = {}
+        self.pedalboard_list = []
         for pb in pbs:
             bundle = pb[Token.BUNDLE]
             title = pb[Token.TITLE]
@@ -1683,6 +1700,7 @@ def _do_restore_data(self, backup_dir: str, on_success=None):
         logging.info("Restoring data backup...")
         cmd = os.path.join(self.homedir, "util", "data-restore.sh")
         job = ArchiveJob.restore(cmd, self.username, os.path.join(backup_dir, self.backup_file), self.data_dir)
+        self._restoring = True
         self.lcd.pstack.push_panel(
             ArchiveProgressPanel(
                 title="Restoring",

tests/v3/test_pedalboards.py

@@ -86,16 +86,15 @@ def get_side_effect(url, **kwargs):
     snapshot()
 
 
-def test_v3_pedalboard_selection_menu_shows_all_boards(
-    v3_system: SystemFixture, nav_handler, make_plugin, snapshot
-):
+def test_v3_pedalboard_selection_menu_shows_all_boards(v3_system: SystemFixture, nav_handler, make_plugin, snapshot):
     """Starting from a loaded pedalboard, open the pedalboard selection menu
     showing 6 boards with distinct titles."""
     handler = v3_system.handler
     hw = v3_system.hw
 
     titles = ["Blues Rig", "Doom Bass", "Shoegaze", "Ambient Pad", "Metal", "Jazz Clean"]
     from unittest.mock import MagicMock
+
     for i, title in enumerate(titles):
         pb = MagicMock()
         pb.title = title
@@ -116,6 +115,74 @@ def test_v3_pedalboard_selection_menu_shows_all_boards(
     snapshot()
 
 
+def _list_side_effect(boards: list[tuple[str, str]]):
+    """mock_get side effect where pedalboard/list returns exactly `boards` as (title, bundle)."""
+
+    def side_effect(url, **_kwargs):
+        resp = MagicMock()
+        resp.status_code = 200
+        if "pedalboard/list" in url:
+            resp.text = json.dumps([{"title": t, "bundle": b} for t, b in boards])
+        elif "snapshot/list" in url:
+            resp.text = json.dumps({"0": "Default"})
+        elif "snapshot/name" in url:
+            resp.text = json.dumps({"name": "Default"})
+        else:
+            resp.text = "{}"
+        return resp
+
+    return side_effect
+
+
+def test_v3_refetch_for_unknown_bundle_does_not_duplicate_list(v3_system: SystemFixture):
+    """last.json naming a board we haven't cached refetches the list. The refetch
+    rebuilds it — a board known before must not appear twice afterwards."""
+    handler = v3_system.handler
+
+    before = [pb.bundle for pb in handler.pedalboard_list]
+    assert before == ["/path/to/rig.pedalboard", "/path/to/new.pedalboard"]
+
+    v3_system.mock_get.side_effect = _list_side_effect(
+        [
+            ("Integration Rig", "/path/to/rig.pedalboard"),
+            ("New Rig", "/path/to/new.pedalboard"),
+            ("Restored Rig", "/path/to/restored.pedalboard"),
+        ]
+    )
+
+    last_json = Path(handler.data_dir) / "last.json"
+    last_json.write_text(json.dumps({"pedalboard": "/path/to/restored.pedalboard"}))
+    os.utime(last_json, (9999, 9999))
+
+    handler.poll_modui_changes()
+
+    assert handler.current
+    assert handler.current.pedalboard.title == "Restored Rig"
+
+    bundles = [pb.bundle for pb in handler.pedalboard_list]
+    assert bundles == [
+        "/path/to/rig.pedalboard",
+        "/path/to/new.pedalboard",
+        "/path/to/restored.pedalboard",
+    ]
+    assert len(handler.pedalboards) == 3
+
+
+def test_v3_refetch_drops_boards_modui_no_longer_lists(v3_system: SystemFixture):
+    """A board deleted in MOD-UI leaves both the dict and the nav list on refetch."""
+    handler = v3_system.handler
+
+    v3_system.mock_get.side_effect = _list_side_effect(
+        [
+            ("Integration Rig", "/path/to/rig.pedalboard"),
+        ]
+    )
+
+    handler.load_pedalboards()
+
+    assert "/path/to/new.pedalboard" not in handler.pedalboards
+    assert [pb.bundle for pb in handler.pedalboard_list] == ["/path/to/rig.pedalboard"]
+
 
 def test_v3_outbound_ws_suppressed_during_pedalboard_change(v3_system: SystemFixture, make_plugin):
     """While a pedalboard change is in flight, outbound param_set messages are dropped."""