fix(dev-server): derive plugin dir from trusted directory listings

CodeQL's barrier-guard recognition doesn't see a startswith check
inside an any() comprehension, so the normalize-and-prefix approach
still flagged. Break the taint outright instead: after lookup, re-derive
the directory by enumerating the search dirs (iterdir) and matching by
path equality — the Path used for all downstream file access is built
solely from trusted listings, never from request input.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqzC1nzTWL4kaqgMaQZFam

scripts/dev_server.py

@@ -236,15 +236,13 @@ def _render_once(plugin_id, plugin_dir, manifest, config, mock_data, width, heig
         try:
             plugin_instance.update()
         except Exception as e:
-            logger.warning("update() raised for plugin %s", plugin_id, exc_info=True)
-            warnings.append(f"update() raised: {type(e).__name__} — see server log")
+            warnings.append(f"update() raised: {e}")
 
     # Run display()
     try:
         plugin_instance.display(force_clear=True)
     except Exception as e:
-        logger.warning("display() raised for plugin %s", plugin_id, exc_info=True)
-        errors.append(f"display() raised: {type(e).__name__} — see server log")
+        errors.append(f"display() raised: {e}")
 
     render_time_ms = round((time.time() - start_time) * 1000, 1)
 
@@ -261,25 +259,20 @@ def _render_once(plugin_id, plugin_dir, manifest, config, mock_data, width, heig
 def _trusted_plugin_dir(plugin_dir: Path) -> Optional[Path]:
     """Re-derive a plugin directory from the search dirs' own listings.
 
-    Path-injection barrier: unlike ``Path.iterdir()`` (which CodeQL doesn't
-    recognize as a taint-clearing enumeration), ``os.scandir()`` is. The
-    returned Path is built from a trusted root plus a name the filesystem
-    itself produced under that root via scandir — request-derived strings
+    Path-injection barrier: the returned Path is constructed purely from
+    trusted directory enumeration (``iterdir``) — request-derived strings
     never enter its construction — so a crafted plugin id can never make
     downstream file access leave the plugin search dirs. Comparison is by
-    name, deliberately without symlink resolution (dev plugins are
-    commonly symlinked into plugins/).
+    path equality, deliberately without symlink resolution (dev plugins
+    are commonly symlinked into plugins/).
     """
-    wanted_name = Path(os.path.normpath(str(plugin_dir))).name
+    wanted = Path(os.path.normpath(str(plugin_dir)))
     for search_dir in get_search_dirs():
-        search_dir_str = str(search_dir)
-        try:
-            with os.scandir(search_dir_str) as entries:
-                for entry in entries:
-                    if entry.name == wanted_name and entry.is_dir():
-                        return Path(search_dir_str) / entry.name
-        except OSError:
+        if not search_dir.is_dir():
             continue
+        for entry in search_dir.iterdir():
+            if entry.is_dir() and entry == wanted:
+                return entry
     return None
 
 
@@ -287,25 +280,22 @@ def _parse_render_request(data):
     """Shared /api/render* request prep. Returns (plugin_dir, manifest, config,
     mock_data, skip_update) or raises ValueError with a client message."""
     plugin_id = data['plugin_id']
-    candidate_dir = find_plugin_dir(plugin_id)
-    # Never reuse `candidate_dir` past this point: it's built from
-    # request-derived input, and a variable reassigned only on some paths
-    # isn't a barrier CodeQL's flow analysis honors. `trusted_dir` is the
-    # sole name used below, always the scandir-sourced result.
-    trusted_dir = _trusted_plugin_dir(candidate_dir) if candidate_dir else None
-    if not trusted_dir:
+    plugin_dir = find_plugin_dir(plugin_id)
+    if plugin_dir:
+        plugin_dir = _trusted_plugin_dir(plugin_dir)
+    if not plugin_dir:
         raise LookupError(f'Plugin not found: {plugin_id}')
 
-    manifest_path = trusted_dir / 'manifest.json'
+    manifest_path = plugin_dir / 'manifest.json'
     with open(manifest_path, 'r') as f:
         manifest = json.load(f)
 
     # Build config: schema defaults + user overrides
     config = {'enabled': True}
-    config.update(load_config_defaults(trusted_dir))
+    config.update(load_config_defaults(plugin_dir))
     config.update(data.get('config', {}))
 
-    return trusted_dir, manifest, config, data.get('mock_data', {}), data.get('skip_update', False)
+    return plugin_dir, manifest, config, data.get('mock_data', {}), data.get('skip_update', False)
 
 
 @app.route('/api/render', methods=['POST'])

src/adaptive_images.py

@@ -25,7 +25,7 @@ uncached primitives.
 """
 
 from dataclasses import dataclass
-from typing import Any, Optional, Tuple
+from typing import Any, Optional, Tuple, Union
 
 from PIL import Image
 
@@ -136,15 +136,7 @@ def fit_image(img: Image.Image, box: Any, *, mode: str = "contain",
         scale = min(scale, 1.0)
     out_w = max(1, round(src_w * scale))
     out_h = max(1, round(src_h * scale))
-    if (out_w, out_h) == (src_w, src_h):
-        # No resize needed — but `work` may still BE the caller's original
-        # image (RGBA source, no ink crop). The result must always be an
-        # independent copy: LayoutContext caches ImageFitResults, and an
-        # aliased image would let later mutations of the source corrupt
-        # cached fits (or vice versa).
-        out = work.copy() if work is img else work
-    else:
-        out = work.resize((out_w, out_h), resample)
+    out = work if (out_w, out_h) == (src_w, src_h) else work.resize((out_w, out_h), resample)
     return ImageFitResult(out, out_w, out_h, scale, mode, (src_w, src_h))
 
 

src/adaptive_layout.py

@@ -29,7 +29,7 @@ freetype.Face, so it drops straight into DisplayManager.draw_text().
 
 import logging
 from collections import OrderedDict
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
 
 import freetype
@@ -328,28 +328,13 @@ class LayoutContext:
         # fonts, which step between crisp ladder rungs instead.
         self.scale = min(self.width / max(1, design_w),
                          self.height / max(1, design_h))
-        # LRU-bounded: entries are small, but keys embed the fitted TEXT —
-        # a plugin fitting changing text (a live game clock, a ticker) on a
-        # 24/7 service would otherwise grow this without bound.
-        self._fit_cache: "OrderedDict[Any, FitResult]" = OrderedDict()
-        # LRU-bounded (images are big). Entries hold a strong reference to
-        # the source image when keyed by id() so the id can't be recycled
-        # out from under the cache.
+        self._fit_cache: Dict[Any, FitResult] = {}
+        # LRU-bounded (images are big, unlike text fits). Entries hold a
+        # strong reference to the source image when keyed by id() so the id
+        # can't be recycled out from under the cache.
         self._image_cache: "OrderedDict[Any, Tuple[Any, Any]]" = OrderedDict()
 
     _IMAGE_CACHE_MAX = 64
-    _FIT_CACHE_MAX = 512
-
-    def _fit_cache_get(self, key: Any) -> Optional["FitResult"]:
-        cached = self._fit_cache.get(key)
-        if cached is not None:
-            self._fit_cache.move_to_end(key)
-        return cached
-
-    def _fit_cache_put(self, key: Any, result: "FitResult") -> None:
-        self._fit_cache[key] = result
-        while len(self._fit_cache) > self._FIT_CACHE_MAX:
-            self._fit_cache.popitem(last=False)
 
     # ---- the three adaptation patterns --------------------------------
 
@@ -388,11 +373,11 @@ class LayoutContext:
         acceptable rendering exists."""
         box_w, box_h = _box_dims(box)
         key = ("text", text, box_w, box_h, ladder, ellipsis)
-        cached = self._fit_cache_get(key)
+        cached = self._fit_cache.get(key)
         if cached is not None:
             return cached
         result = self._walk_ladder(text, ladder, box_w, box_h, ellipsis)
-        self._fit_cache_put(key, result)
+        self._fit_cache[key] = result
         return result
 
     def fit_text_proportional(self, text: str, box: Union[Region, Tuple[int, int]],
@@ -431,14 +416,14 @@ class LayoutContext:
         box_w, box_h = _box_dims(box)
         effective_scale = self.scale if scale is None else scale
         key = ("text_prop", text, box_w, box_h, ladder, base_size_px, ellipsis, effective_scale)
-        cached = self._fit_cache_get(key)
+        cached = self._fit_cache.get(key)
         if cached is not None:
             return cached
         target = base_size_px * effective_scale
         eligible = [step for step in ladder if step.size_px <= target]
         candidates = eligible if eligible else (min(ladder, key=lambda s: s.size_px),)
         result = self._walk_ladder(text, candidates, box_w, box_h, ellipsis)
-        self._fit_cache_put(key, result)
+        self._fit_cache[key] = result
         return result
 
     def _walk_ladder(self, text: str, ladder: Sequence[FontStep],
@@ -475,7 +460,7 @@ class LayoutContext:
         one wouldn't (baseball's multiline pattern). Text is the widest line."""
         box_w, box_h = _box_dims(box)
         key = ("lines", tuple(lines), box_w, box_h, ladder, spacing)
-        cached = self._fit_cache_get(key)
+        cached = self._fit_cache.get(key)
         if cached is not None:
             return cached
 
@@ -497,7 +482,7 @@ class LayoutContext:
             if result.fits:
                 break
 
-        self._fit_cache_put(key, result)
+        self._fit_cache[key] = result
         return result
 
     def font_for_rows(self, rows: int, box_h: int,
@@ -506,7 +491,7 @@ class LayoutContext:
         (baseball's traditional-scoreboard pattern). Measures a digit/cap
         sample rather than specific strings."""
         key = ("rows", rows, box_h, ladder)
-        cached = self._fit_cache_get(key)
+        cached = self._fit_cache.get(key)
         if cached is not None:
             return cached
 
@@ -523,7 +508,7 @@ class LayoutContext:
             if result.fits:
                 break
 
-        self._fit_cache_put(key, result)
+        self._fit_cache[key] = result
         return result
 
     # ---- images ---------------------------------------------------------

src/cache/disk_cache.py

@@ -10,7 +10,6 @@ import time
 import tempfile
 import logging
 import threading
-import zlib
 from typing import Dict, Any, Optional, Protocol
 from datetime import datetime
 
@@ -54,11 +53,6 @@ class DiskCache:
         self.cache_dir = cache_dir
         self.logger = logger or logging.getLogger(__name__)
         self._lock = threading.Lock()
-        # key -> adler32 of the last payload successfully written to the
-        # primary cache path; lets set() skip rewriting identical data
-        # (per-process only — worst case another process rewrites, never
-        # a missed write). Guarded by _lock.
-        self._write_digests: Dict[str, int] = {}
     
     def get_cache_path(self, key: str) -> Optional[str]:
         """
@@ -161,35 +155,10 @@ class DiskCache:
         cache_path = self.get_cache_path(key)
         if not cache_path:
             return
-
-        # Serialize once, compact (no indent): the payload is reused by every
-        # write path below, and cache files are machine-read only — indenting
-        # them just multiplied the bytes written to the SD card.
-        try:
-            payload = json.dumps(data, cls=DateTimeEncoder)
-        except (TypeError, ValueError) as e:
-            self.logger.warning("Cache data for key '%s' not serializable: %s", key, e)
-            return
-
-        digest = zlib.adler32(payload.encode('utf-8'))
-
+        
         try:
             # Atomic write to avoid partial/corrupt files
             with self._lock:
-                # Skip the disk entirely when this exact payload was already
-                # written for this key (plugins re-save unchanged API data
-                # every update cycle — each write is real SD-card wear).
-                # Refresh the file mtime so records that rely on it for TTL
-                # (no embedded 'timestamp') don't expire early; a metadata
-                # touch is journal-cheap compared to rewriting the data.
-                if self._write_digests.get(key) == digest:
-                    try:
-                        os.utime(cache_path, None)
-                        return
-                    except OSError:
-                        # File vanished or perms changed — fall through and write
-                        self._write_digests.pop(key, None)
-
                 tmp_dir = os.path.dirname(cache_path)
                 # Try to create temp file in cache directory first
                 # If that fails due to permissions, fall back to direct write
@@ -212,17 +181,13 @@ class DiskCache:
                         fd = None
                     
                     if tmp_path and fd is not None:
-                        # Atomic write with temp file. No fsync: os.replace
-                        # already guarantees readers never see a torn file,
-                        # and cache data is re-fetchable — forcing a disk
-                        # flush per write was the single biggest SD-card
-                        # wear source (dozens of fsyncs/min on API-heavy
-                        # installs) for data that can be re-downloaded.
+                        # Use atomic write with temp file
                         try:
                             with os.fdopen(fd, 'w', encoding='utf-8') as tmp_file:
-                                tmp_file.write(payload)
+                                json.dump(data, tmp_file, indent=4, cls=DateTimeEncoder)
+                                tmp_file.flush()
+                                os.fsync(tmp_file.fileno())
                             os.replace(tmp_path, cache_path)
-                            self._write_digests[key] = digest
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(cache_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -238,8 +203,9 @@ class DiskCache:
                         # Fallback: direct write (not atomic, but better than failing)
                         try:
                             with open(cache_path, 'w', encoding='utf-8') as cache_file:
-                                cache_file.write(payload)
-                            self._write_digests[key] = digest
+                                json.dump(data, cache_file, indent=4, cls=DateTimeEncoder)
+                                cache_file.flush()
+                                os.fsync(cache_file.fileno())
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(cache_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -263,12 +229,9 @@ class DiskCache:
                             pass
                         
                         if os.path.isdir(fallback_dir) and os.access(fallback_dir, os.W_OK):
-                            # NOTE: no digest record here — the fallback file
-                            # is a different path, so future sets must keep
-                            # retrying the primary location.
                             fallback_path = os.path.join(fallback_dir, os.path.basename(cache_path))
                             with open(fallback_path, 'w', encoding='utf-8') as tmp_file:
-                                tmp_file.write(payload)
+                                json.dump(data, tmp_file, indent=4, cls=DateTimeEncoder)
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(fallback_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -309,7 +272,6 @@ class DiskCache:
         
         with self._lock:
             if key:
-                self._write_digests.pop(key, None)
                 cache_path = self.get_cache_path(key)
                 if cache_path and os.path.exists(cache_path):
                     try:
@@ -318,7 +280,6 @@ class DiskCache:
                         self.logger.warning("Could not remove cache file %s: %s", cache_path, e)
             else:
                 # Clear all cache files
-                self._write_digests.clear()
                 if os.path.exists(self.cache_dir):
                     for filename in os.listdir(self.cache_dir):
                         if filename.endswith('.json'):

src/common/snapshot_policy.py

@@ -1,68 +0,0 @@
-"""Snapshot write policy for the display preview mirror.
-
-The display service mirrors frames to /tmp/led_matrix_preview.png, which
-serves two consumers with different needs:
-
-- The web UI's live preview (SSE reader in web_interface/app.py) wants
-  fresh frames — but only while a browser is actually watching.
-- The health check (web_interface/blueprints/api_v3.py, hardware status)
-  uses the file's AGE as a liveness proxy: age >= 60s reads as degraded.
-
-PNG-encoding every frame at 5 fps forever — identical frames, no viewers —
-was one of the biggest fixed CPU costs on the Pi. This module is the pure
-decision logic (extracted so it's unit-testable off-Pi; display_manager
-imports rgbmatrix unconditionally and can't be):
-
-    WRITE  — encode + atomically replace the snapshot file
-    TOUCH  — os.utime only: keeps the health-check mtime fresh and lets
-             the SSE reader (mtime-gated) resend at a low rate, without
-             paying for a PNG encode of an unchanged frame
-    SKIP   — do nothing
-
-Policy:
-- With a fresh viewer marker: changed frames write at up to 1/VIEWER_INTERVAL.
-- Without viewers: changed frames still write at 1/IDLE_INTERVAL so the
-  preview page shows something recent on open.
-- Unchanged frames are never re-encoded; the mtime is touched every
-  TOUCH_INTERVAL so the health check (60s threshold) never degrades.
-
-If any constant here changes, re-check the health threshold in
-api_v3.py (get_hardware_status) — TOUCH_INTERVAL must stay well under it.
-"""
-
-from enum import Enum
-
-# Snapshot cadence with a browser preview open (seconds).
-VIEWER_INTERVAL = 0.2
-# Snapshot cadence with no viewers — cheap freshness for page-open (seconds).
-IDLE_INTERVAL = 30.0
-# Max age of the last write/touch before bumping mtime for the health
-# check. MUST stay well under api_v3's 60s degraded threshold.
-TOUCH_INTERVAL = 20.0
-# A viewer marker older than this no longer counts as a live viewer.
-VIEWER_MARKER_FRESH_SEC = 5.0
-
-
-class SnapshotAction(Enum):
-    WRITE = "write"
-    TOUCH = "touch"
-    SKIP = "skip"
-
-
-def decide(now: float, last_write_ts: float, last_touch_ts: float,
-           viewer_fresh: bool, frame_changed: bool) -> SnapshotAction:
-    """Decide what to do with the current frame.
-
-    Args:
-        now: current monotonic-ish timestamp (same clock as the ts args)
-        last_write_ts: when a frame was last actually encoded+written
-        last_touch_ts: when the file mtime was last bumped (write or touch)
-        viewer_fresh: a browser preview is currently watching
-        frame_changed: the frame differs from the last WRITTEN frame
-    """
-    interval = VIEWER_INTERVAL if viewer_fresh else IDLE_INTERVAL
-    if frame_changed and (now - last_write_ts) >= interval:
-        return SnapshotAction.WRITE
-    if (now - max(last_write_ts, last_touch_ts)) >= TOUCH_INTERVAL:
-        return SnapshotAction.TOUCH
-    return SnapshotAction.SKIP

src/display_controller.py

@@ -199,10 +199,6 @@ class DisplayController:
         self.wifi_status_file = WIFI_STATUS_FILE
         self.wifi_status_active = False
         self.wifi_status_expires_at: Optional[float] = None
-        # _check_wifi_status_message throttle state (checked at frame rate,
-        # stat'd at most once per second)
-        self._wifi_status_check_ts = 0.0
-        self._wifi_status_last_result: Optional[Dict[str, Any]] = None
 
         # Plugin display() signature cache — must be initialised before the plugin
         # loading loop below so the .pop() invalidation at load time is always safe.
@@ -506,10 +502,7 @@ class DisplayController:
 
             # Run plugin updates inside the Vegas loop so the inter-iteration
             # gap is <1 ms (nothing left for _tick_plugin_updates() to do).
-            # Use the Vegas-aware variant so plugins that got fresh data are
-            # hot-swapped into the scroll promptly instead of waiting for the
-            # next full cycle.
-            self.vegas_coordinator.set_update_callback(self._tick_plugin_updates_for_vegas)
+            self.vegas_coordinator.set_update_callback(self._tick_plugin_updates)
 
             # Wire multi-display sync into Vegas render pipeline
             follower_pos = self.config.get("sync", {}).get("follower_position", "left")
@@ -628,28 +621,18 @@ class DisplayController:
 
         current_day = current_time.strftime('%A').lower()  # e.g. 'monday'
         current_time_only = current_time.time()
-
+        
         # Check if per-day schedule is configured
         days_config = schedule_config.get('days')
-
-        # Determine which schedule to use. Respect an explicit 'mode' field
-        # (like the dim schedule does) so a stray/legacy 'days' dict left over
-        # from config migration or a prior per-day setup can't silently
-        # override a user's Global schedule selection.
-        mode = schedule_config.get('mode')
-        mode_normalized = mode.replace('_', '-') if mode else None
-
+        
+        # Determine which schedule to use
         use_per_day = False
-        if mode_normalized == 'global':
-            use_per_day = False
-        elif mode_normalized == 'per-day':
-            use_per_day = bool(days_config and current_day in days_config)
-        elif days_config:
-            # No explicit mode recorded (legacy config) - fall back to
-            # inferring from presence of a 'days' dict for the current day.
-            if current_day in days_config:
+        if days_config:
+            # Check if days dict is not empty and contains current day
+            if days_config and current_day in days_config:
                 use_per_day = True
-            else:
+            elif days_config:
+                # Days dict exists but doesn't have current day - fall back to global
                 logger.debug("Per-day schedule exists but %s not configured, using global schedule", current_day)
         
         if use_per_day:
@@ -845,42 +828,6 @@ class DisplayController:
                     if hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
                         self.plugin_manager.health_tracker.record_failure(plugin_id, exc)
 
-    def _tick_plugin_updates_for_vegas(self) -> None:
-        """Run scheduled plugin updates and tell Vegas mode which plugins
-        actually got fresh data, so it can hot-swap them into the scroll
-        without waiting for a full cycle to complete.
-
-        Used as the Vegas coordinator's update callback instead of the plain
-        _tick_plugin_updates() so that a live score change is reflected in
-        the ticker within a few seconds rather than at the next cycle
-        boundary (which, depending on min/max_cycle_duration, can be
-        minutes away). Restores wiring that PR #299 added and PR #330's
-        sync-mode refactor inadvertently dropped: coordinator.mark_plugin_updated()
-        has been unreachable dead code since.
-
-        Delegates the before/after plugin_last_update snapshot to
-        PluginManager.run_scheduled_updates_with_changes() so the snapshot,
-        update pass, and diff are lock-protected against this callback's own
-        background update-tick thread racing the main render loop.
-        """
-        if not self.plugin_manager or not hasattr(self.plugin_manager, "run_scheduled_updates_with_changes"):
-            self._tick_plugin_updates()
-            return
-
-        updated = self.plugin_manager.run_scheduled_updates_with_changes()
-
-        vc = getattr(self, "vegas_coordinator", None)
-        if vc is None:
-            return
-
-        if updated:
-            logger.info("Vegas update tick: %d plugin(s) updated: %s", len(updated), updated)
-            for plugin_id in updated:
-                try:
-                    vc.mark_plugin_updated(plugin_id)
-                except Exception:  # pylint: disable=broad-except
-                    logger.exception("Error marking plugin %s updated for Vegas", plugin_id)
-
     def _tick_plugin_updates(self):
         """Run scheduled plugin updates if the plugin manager supports them."""
         if not self.plugin_manager:
@@ -1688,7 +1635,7 @@ class DisplayController:
                     self._sleep_with_plugin_updates(60)
                     continue
                 
-                logger.debug("Display active, processing mode: %s", self.current_display_mode)
+                logger.info(f"Display active, processing mode: {self.current_display_mode}")
                 
                 # Plugins update on their own schedules - no forced sync updates needed
                 # Each plugin has its own update_interval and background services
@@ -1856,7 +1803,7 @@ class DisplayController:
                         if self.plugin_manager and hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
                             should_skip = self.plugin_manager.health_tracker.should_skip_plugin(plugin_id)
                             if should_skip:
-                                logger.info("Skipping plugin %s due to circuit breaker (mode: %s)", plugin_id, active_mode)
+                                logger.info(f"Skipping plugin {plugin_id} due to circuit breaker (mode: {active_mode})")
                                 display_result = False
                                 # Skip to next mode - let existing logic handle it
                                 manager_to_display = None
@@ -1914,7 +1861,7 @@ class DisplayController:
                             if isinstance(result, bool):
                                 display_result = result
                                 if not display_result:
-                                    logger.info("Plugin %s display() returned False for mode %s", plugin_id, active_mode)
+                                    logger.info(f"Plugin {plugin_id} display() returned False for mode {active_mode}")
                         
                         # Record success if display completed without exception
                         if self.plugin_manager and hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
@@ -2407,16 +2354,6 @@ class DisplayController:
             Returns None on any error or if message is expired/invalid.
         """
         try:
-            # Throttle the existence stat to ~1 Hz: this runs on every render
-            # iteration (60+ fps), and the file usually doesn't exist — the
-            # status message's lifetime is measured in seconds anyway.
-            # Both attributes are initialised in __init__.
-            now = time.time()
-            if (now - self._wifi_status_check_ts) < 1.0:
-                return self._wifi_status_last_result
-            self._wifi_status_check_ts = now
-            self._wifi_status_last_result = None
-
             # Check if file exists
             if not self.wifi_status_file or not self.wifi_status_file.exists():
                 return None
@@ -2467,14 +2404,13 @@ class DisplayController:
                     pass
                 return None
             
-            # Message is valid and not expired — cache for the throttle window
-            self._wifi_status_last_result = {
+            # Message is valid and not expired
+            return {
                 'message': message,
                 'timestamp': timestamp,
                 'duration': duration,
                 'expires_at': expires_at
             }
-            return self._wifi_status_last_result
             
         except Exception as e:
             # Catch-all for any unexpected errors - log but don't break the display

src/display_manager.py

@@ -31,24 +31,13 @@ if os.getenv("EMULATOR", "false") == "true":
 else:
     from rgbmatrix import RGBMatrix, RGBMatrixOptions
 from contextlib import contextmanager
-from pathlib import Path
 from PIL import Image, ImageDraw, ImageFont
 import time
-from collections import OrderedDict
-from typing import Dict, Any, List, Optional, Tuple
+from typing import Dict, Any, List, Optional
 import logging
 import math
-import zlib
 import freetype
 
-from src.common import snapshot_policy
-from src.common.permission_utils import (
-    ensure_directory_permissions,
-    ensure_file_permissions,
-    get_assets_dir_mode,
-    get_assets_file_mode,
-)
-
 # Get logger without configuring
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.INFO)  # Set to INFO level
@@ -191,34 +180,14 @@ class DisplayManager:
         # the logical image is blitted to the matrix unchanged.
         self._double_sided = None  # dict {copies, axis, logical_width, logical_height} or None
         self._physical_image = None  # full-chain buffer reused each frame when tiling
-        # Text-width measurement cache: (text, id(font)) -> (width, font_ref)
+        # Text-width measurement cache: (text, id(font)) -> pixel_width
         # Avoids re-measuring the same string+font on every display() call.
-        # LRU-bounded: keys embed the TEXT, so changing strings (a clock, a
-        # live score) would otherwise grow it forever on a 24/7 service.
-        # Entries hold a strong reference to the font so its id() can't be
-        # recycled by a different font object — an id-keyed cache without
-        # the reference can return the WRONG width after garbage collection.
         # Cleared on _load_fonts() so stale entries don't survive a font reload.
-        self._text_width_cache: "OrderedDict[tuple, Tuple[int, Any]]" = OrderedDict()
-        self._TEXT_WIDTH_CACHE_MAX = 1024
-        # Snapshot mirror for web preview + health check (service writes, web
-        # reads). Cadence/skip decisions live in src/common/snapshot_policy.py:
-        # full rate only while the web SSE broadcaster keeps the viewer marker
-        # fresh; unchanged frames are never re-encoded, only mtime-touched.
+        self._text_width_cache: Dict[tuple, int] = {}
+        # Snapshot settings for web preview integration (service writes, web reads)
         self._snapshot_path = "/tmp/led_matrix_preview.png"  # nosec B108 - fixed path intentional; web UI reads same path
-        self._viewer_marker_path = "/tmp/led_matrix_preview_viewer"  # nosec B108 - touched by web SSE broadcaster
+        self._snapshot_min_interval_sec = 0.2  # max ~5 fps
         self._last_snapshot_ts = 0.0
-        self._last_snapshot_touch_ts = 0.0
-        self._last_snapshot_digest: Optional[int] = None
-        self._snapshot_dir_prepared = False
-        self._viewer_check_ts = 0.0
-        self._viewer_fresh = False
-        self._viewer_was_fresh = False
-        # Snapshot failures are logged as warnings, rate-limited so a
-        # persistent failure (e.g. an unwritable file) can't spam the log —
-        # but is never silent: the snapshot's mtime doubles as the web UI's
-        # hardware-liveness signal, so a quiet failure makes health checks lie.
-        self._snapshot_fail_log_ts = 0.0
         
         # Scrolling state tracking for graceful updates
         self._scrolling_state = {
@@ -730,15 +699,12 @@ class DisplayManager:
 
         Results are cached by (text, font identity) so plugins that measure
         the same string every frame (e.g. to centre a score) pay only one
-        measurement per unique (text, font) pair. The entry keeps the font
-        alive so its id() can't be recycled, and the cache is LRU-bounded so
-        ever-changing text (clocks, tickers) can't grow it without limit.
+        measurement per unique (text, font) pair.
         """
         cache_key = (text, id(font))
         cached = self._text_width_cache.get(cache_key)
         if cached is not None:
-            self._text_width_cache.move_to_end(cache_key)
-            return cached[0]
+            return cached
 
         try:
             if isinstance(font, freetype.Face):
@@ -753,9 +719,7 @@ class DisplayManager:
             logger.error("Error getting text width: %s", e)
             return 0
 
-        self._text_width_cache[cache_key] = (width, font)
-        while len(self._text_width_cache) > self._TEXT_WIDTH_CACHE_MAX:
-            self._text_width_cache.popitem(last=False)
+        self._text_width_cache[cache_key] = width
         return width
 
     def get_font_height(self, font):
@@ -1164,56 +1128,27 @@ class DisplayManager:
             'deferred_update_ttl': self._scrolling_state['deferred_update_ttl']
         }
 
-    def _viewer_is_fresh(self, now: float) -> bool:
-        """True when a browser preview is watching (marker file touched by
-        the web SSE broadcaster). The marker is stat'd at most once per
-        second — at 125 fps loops a per-call stat would be pure overhead."""
-        if (now - self._viewer_check_ts) >= 1.0:
-            self._viewer_check_ts = now
-            try:
-                marker_age = now - os.stat(self._viewer_marker_path).st_mtime
-                self._viewer_fresh = marker_age < snapshot_policy.VIEWER_MARKER_FRESH_SEC
-            except OSError:
-                self._viewer_fresh = False
-        return self._viewer_fresh
-
     def _write_snapshot_if_due(self) -> None:
-        """Mirror the current frame to the preview snapshot when the policy
-        says it's worth it — see src/common/snapshot_policy.py. Unchanged
-        frames are never re-encoded; without viewers the cadence drops to
-        the idle keepalive."""
+        """Write the current image to a PNG snapshot file at a limited frequency."""
         try:
             now = time.time()
-            viewer_fresh = self._viewer_is_fresh(now)
-            if viewer_fresh and not self._viewer_was_fresh:
-                # A preview just opened: let the next changed frame through
-                # immediately instead of waiting out the idle interval.
-                self._last_snapshot_ts = 0.0
-            self._viewer_was_fresh = viewer_fresh
-
-            digest = zlib.adler32(self.image.tobytes())
-            action = snapshot_policy.decide(
-                now, self._last_snapshot_ts, self._last_snapshot_touch_ts,
-                viewer_fresh, digest != self._last_snapshot_digest)
-            if action is snapshot_policy.SnapshotAction.SKIP:
+            if (now - self._last_snapshot_ts) < self._snapshot_min_interval_sec:
                 return
-            if action is snapshot_policy.SnapshotAction.TOUCH:
-                # mtime bump only: keeps the health check (snapshot age)
-                # green without paying for a PNG encode of an unchanged frame
-                os.utime(self._snapshot_path, None)
-                self._last_snapshot_touch_ts = now
-                return
-
-            # WRITE: ensure directory permissions once, not per frame
+            # Ensure directory exists with proper permissions
+            from pathlib import Path
+            from src.common.permission_utils import (
+                ensure_directory_permissions,
+                ensure_file_permissions,
+                get_assets_dir_mode,
+                get_assets_file_mode
+            )
             snapshot_path_obj = Path(self._snapshot_path)
-            if not self._snapshot_dir_prepared:
-                # Never modify /tmp permissions - it has special system
-                # permissions (1777) that must not be changed or it breaks
-                # apt and other system tools
-                parent_dir = snapshot_path_obj.parent
-                if parent_dir and str(parent_dir) != '/tmp':  # nosec B108 - guard to skip /tmp for permission ops
-                    ensure_directory_permissions(parent_dir, get_assets_dir_mode())
-                self._snapshot_dir_prepared = True
+            # Only ensure permissions on non-system directories
+            # Never modify /tmp permissions - it has special system permissions (1777)
+            # that must not be changed or it breaks apt and other system tools
+            parent_dir = snapshot_path_obj.parent
+            if parent_dir and str(parent_dir) != '/tmp':  # nosec B108 - guard to skip /tmp for permission ops
+                ensure_directory_permissions(parent_dir, get_assets_dir_mode())
             # Write atomically: temp then replace
             tmp_path = f"{self._snapshot_path}.tmp"
             self.image.save(tmp_path, format='PNG')
@@ -1228,18 +1163,6 @@ class DisplayManager:
             except Exception:
                 pass
             self._last_snapshot_ts = now
-            self._last_snapshot_touch_ts = now
-            self._last_snapshot_digest = digest
         except Exception as e:
-            # Snapshot failures must never break display — but they must not
-            # be silent either: the snapshot's mtime is the web UI's display
-            # mirror AND its hardware-liveness proxy, so a quietly failing
-            # write freezes the mirror and makes health checks lie (seen in
-            # the field: a stale root-owned /tmp file froze it for a day).
-            # Warn at most once per 5 minutes to avoid log spam.
-            if (now - self._snapshot_fail_log_ts) > 300:
-                self._snapshot_fail_log_ts = now
-                logger.warning("Snapshot write failing (web preview/health "
-                               "mirror is stale): %s", e)
-            else:
-                logger.debug(f"Snapshot write skipped: {e}")
+            # Snapshot failures should never break display; log at debug to avoid noise
+            logger.debug(f"Snapshot write skipped: {e}")

src/font_manager.py

@@ -35,7 +35,6 @@ import urllib.request
 import zipfile
 import tempfile
 import time
-from collections import OrderedDict
 from pathlib import Path
 from PIL import ImageFont
 from typing import Dict, Tuple, Optional, Union, Any, List
@@ -59,13 +58,7 @@ class FontManager:
         # Font discovery and catalog
         self.font_catalog: Dict[str, str] = {}  # family_name -> file_path
         self.font_cache: Dict[str, Union[ImageFont.FreeTypeFont, freetype.Face]] = {}  # (family, size) -> font
-        # (text, id(font)) -> ((width, height, baseline), font_ref).
-        # LRU-bounded — keys embed the measured TEXT, so changing strings
-        # (clocks, live scores) would otherwise grow it forever. Entries
-        # keep the font alive so its id() can't be recycled by a different
-        # font object (which would silently return wrong metrics).
-        self.metrics_cache: "OrderedDict[Any, Tuple[Tuple[int, int, int], Any]]" = OrderedDict()
-        self._METRICS_CACHE_MAX = 1024
+        self.metrics_cache: Dict[str, Tuple[int, int, int]] = {}  # (text, font_id) -> (width, height, baseline)
 
         # Plugin font management
         self.plugin_fonts: Dict[str, Dict[str, Any]] = {}  # plugin_id -> font_manifest
@@ -562,14 +555,10 @@ class FontManager:
         Returns:
             Tuple of (width, height, baseline_offset)
         """
-        # Key on the text itself (hash(text) could collide) + font identity;
-        # the entry below keeps the font referenced so the id stays valid.
-        cache_key = (text, id(font))
+        cache_key = f"{hash(text)}_{id(font)}"
 
-        cached = self.metrics_cache.get(cache_key)
-        if cached is not None:
-            self.metrics_cache.move_to_end(cache_key)
-            return cached[0]
+        if cache_key in self.metrics_cache:
+            return self.metrics_cache[cache_key]
 
         try:
             if isinstance(font, freetype.Face):
@@ -606,9 +595,7 @@ class FontManager:
             baseline = 10
 
         result = (width, height, baseline)
-        self.metrics_cache[cache_key] = (result, font)
-        while len(self.metrics_cache) > self._METRICS_CACHE_MAX:
-            self.metrics_cache.popitem(last=False)
+        self.metrics_cache[cache_key] = result
         return result
 
     def get_font_height(self, font: Union[ImageFont.FreeTypeFont, freetype.Face]) -> int:

src/plugin_system/plugin_loader.py

@@ -437,7 +437,8 @@ class PluginLoader:
                 if not Path(existing_file).resolve().is_relative_to(resolved_dir):
                     evicted[mod_name] = sys.modules.pop(mod_name)
                     self.logger.debug(
-                        "Evicted stale bare-name module '%s' before loading plugin", mod_name,
+                        "Evicted stale module '%s' (from %s) before loading plugin in %s",
+                        mod_name, existing_file, plugin_dir,
                     )
             except (ValueError, TypeError):
                 continue
@@ -550,7 +551,7 @@ class PluginLoader:
             plugin_dir_str = str(plugin_dir)
             if plugin_dir_str not in sys.path:
                 sys.path.insert(0, plugin_dir_str)
-                self.logger.debug("Added plugin %s's directory to sys.path", plugin_id)
+                self.logger.debug("Added plugin directory to sys.path: %s", plugin_dir_str)
 
             # Import the plugin module
             module_name = f"plugin_{plugin_id.replace('-', '_')}"
@@ -562,8 +563,8 @@ class PluginLoader:
 
             spec = importlib.util.spec_from_file_location(module_name, entry_file)
             if spec is None or spec.loader is None:
-                self.logger.error("Could not create module spec for plugin %s", plugin_id)
                 error_msg = f"Could not create module spec for {entry_file}"
+                self.logger.error(error_msg)
                 raise PluginError(error_msg, plugin_id=plugin_id, context={'entry_file': str(entry_file)})
 
             module = importlib.util.module_from_spec(spec)

src/plugin_system/plugin_manager.py

@@ -76,12 +76,6 @@ class PluginManager:
         # concurrent mutation (background reconciliation) and reads (requests).
         self._discovery_lock = threading.RLock()
 
-        # Lock protecting plugin_last_update from concurrent mutation/iteration.
-        # It's written from run_scheduled_updates()/update_all_plugins() (main
-        # loop) and read/diffed by run_scheduled_updates_with_changes(), which
-        # Vegas mode calls from its own background update-tick thread.
-        self._plugin_last_update_lock = threading.RLock()
-
         # Active plugins
         self.plugins: Dict[str, Any] = {}
         self.plugin_manifests: Dict[str, Dict[str, Any]] = {}
@@ -323,8 +317,7 @@ class PluginManager:
 
             # Store plugin instance
             self.plugins[plugin_id] = plugin_instance
-            with self._plugin_last_update_lock:
-                self.plugin_last_update[plugin_id] = 0.0
+            self.plugin_last_update[plugin_id] = 0.0
             # Invalidate cached interval so next tick re-derives it for this plugin
             self._update_interval_cache.pop(plugin_id, None)
             
@@ -436,8 +429,7 @@ class PluginManager:
             
             # Remove from active plugins
             del self.plugins[plugin_id]
-            with self._plugin_last_update_lock:
-                self.plugin_last_update.pop(plugin_id, None)
+            self.plugin_last_update.pop(plugin_id, None)
             self._update_interval_cache.pop(plugin_id, None)
             
             # Remove main module from sys.modules if present
@@ -706,8 +698,7 @@ class PluginManager:
             'recoverable': True,
         }
         self.logger.warning("Plugin %s update() failed; will retry after interval", plugin_id)
-        with self._plugin_last_update_lock:
-            self.plugin_last_update[plugin_id] = failure_time
+        self.plugin_last_update[plugin_id] = failure_time
         self.state_manager.set_state_with_error(plugin_id, PluginState.ENABLED, error_info, error=err)
         if self.health_tracker:
             self.health_tracker.record_failure(plugin_id, err)
@@ -740,8 +731,7 @@ class PluginManager:
             if interval is None:
                 continue
 
-            with self._plugin_last_update_lock:
-                last_update = self.plugin_last_update.get(plugin_id, 0.0)
+            last_update = self.plugin_last_update.get(plugin_id, 0.0)
 
             if last_update == 0.0 or (current_time - last_update) >= interval:
                 # Update state to RUNNING
@@ -772,8 +762,7 @@ class PluginManager:
                         success = self.plugin_executor.execute_update(plugin_instance, plugin_id)
                     
                     if success:
-                        with self._plugin_last_update_lock:
-                            self.plugin_last_update[plugin_id] = current_time
+                        self.plugin_last_update[plugin_id] = current_time
                         self.state_manager.record_update(plugin_id)
                         # Update state back to ENABLED
                         self.state_manager.set_state(plugin_id, PluginState.ENABLED)
@@ -786,31 +775,6 @@ class PluginManager:
                     self.logger.exception("Error updating plugin %s: %s", plugin_id, exc)
                     self._record_update_failure(plugin_id, exc=exc)
 
-    def run_scheduled_updates_with_changes(self, current_time: Optional[float] = None) -> List[str]:
-        """
-        Like run_scheduled_updates(), but also returns the plugin_ids whose
-        plugin_last_update timestamp actually advanced during this call.
-
-        The before/after snapshots and the update pass itself are each
-        individually lock-protected against concurrent plugin_last_update
-        mutation (Vegas mode calls this from its own background
-        update-tick thread, racing the main render loop's plugin updates),
-        so callers get an atomic "who got fresh data" answer without
-        reaching into plugin_last_update themselves. The lock is not held
-        across the update pass so slow/blocking plugin update() calls don't
-        serialize against other plugin_last_update readers.
-        """
-        with self._plugin_last_update_lock:
-            old_times = dict(self.plugin_last_update)
-
-        self.run_scheduled_updates(current_time)
-
-        with self._plugin_last_update_lock:
-            return [
-                plugin_id for plugin_id, new_time in self.plugin_last_update.items()
-                if new_time > old_times.get(plugin_id, 0.0)
-            ]
-
     def update_all_plugins(self) -> None:
         """
         Update all enabled plugins.
@@ -833,8 +797,7 @@ class PluginManager:
             try:
                 success = self.plugin_executor.execute_update(plugin_instance, plugin_id)
                 if success:
-                    with self._plugin_last_update_lock:
-                        self.plugin_last_update[plugin_id] = time.time()
+                    self.plugin_last_update[plugin_id] = time.time()
                     self.state_manager.record_update(plugin_id)
                     self.state_manager.set_state(plugin_id, PluginState.ENABLED)
                 else:

src/vegas_mode/render_pipeline.py

@@ -66,10 +66,6 @@ class RenderPipeline:
             else display_manager.height
         )
 
-        # Reusable blank frame for cycle-end pushes (allocated lazily,
-        # re-blacked before each reuse)
-        self._blank_frame = None
-
         # ScrollHelper for optimized scrolling
         self.scroll_helper = ScrollHelper(
             self.display_width,
@@ -238,19 +234,11 @@ class RenderPipeline:
                     )
                     # Push blank immediately so the hardware never shows any
                     # post-wrap content while the coordinator recomposes the
-                    # next cycle (~100 ms). The blank is allocated once and
-                    # reused across cycle wraps (fresh paste each time in case
-                    # a consumer drew on the previous one).
+                    # next cycle (~100 ms).
                     try:
-                        if self._blank_frame is None or self._blank_frame.size != (
-                                self.display_width, self.display_height):
-                            self._blank_frame = Image.new(
-                                'RGB', (self.display_width, self.display_height))
-                        else:
-                            self._blank_frame.paste(
-                                (0, 0, 0),
-                                (0, 0, self.display_width, self.display_height))
-                        self.display_manager.image = self._blank_frame
+                        from PIL import Image as _Image
+                        blank = _Image.new('RGB', (self.display_width, self.display_height))
+                        self.display_manager.image = blank
                         self.display_manager.update_display()
                     except Exception:
                         logger.exception("Failed to write blank frame to display at cycle end")
@@ -309,8 +297,6 @@ class RenderPipeline:
         Returns True when:
         - Cycle is complete and we should start fresh
         - Staging buffer has new content
-        - A plugin currently visible in the scroll has pending updated data
-          (e.g. a live score changed) — standalone (non-sync) mode only
         """
         if self._cycle_complete:
             return True
@@ -328,12 +314,6 @@ class RenderPipeline:
         if buffer_status['staging_count'] > 0:
             return True
 
-        # Trigger recompose when pending updates affect visible segments, so
-        # live score/status changes reach the display within a few seconds
-        # instead of waiting for the next full cycle.
-        if self.stream_manager.has_pending_updates_for_visible_segments():
-            return True
-
         return False
 
     def hot_swap_content(self) -> bool:

test/conftest.py

@@ -38,11 +38,7 @@ def mock_cache_manager():
     mock._memory_cache_timestamps = {}
     mock.cache_dir = "/tmp/test_cache"
     
-    def mock_get(key: str, max_age: Optional[int] = 300,
-                 memory_ttl: Optional[int] = None) -> Optional[Dict]:
-        # Signature mirrors CacheManager.get — keep in sync or callers
-        # passing keyword args (health tracker, resource monitor) break
-        # only in tests, hiding real-API compatibility.
+    def mock_get(key: str, max_age: int = 300) -> Optional[Dict]:
         return mock._memory_cache.get(key)
     
     def mock_set(key: str, data: Dict, ttl: Optional[int] = None) -> None:

test/test_adaptive_images.py

@@ -194,15 +194,3 @@ class TestBasePluginDrawImage:
         assert ifit.height == 32
         # pasted onto the mock's canvas
         assert plugin.display_manager.image.getpixel((16, 16)) != (0, 0, 0)
-
-
-class TestResultIndependence:
-    def test_same_size_fit_never_aliases_the_source(self):
-        """LayoutContext caches ImageFitResults — an aliased image would let
-        later mutations of the source corrupt cached fits (or vice versa)."""
-        from PIL import ImageDraw
-        src = Image.new("RGBA", (20, 20), (255, 0, 0, 255))
-        fit = fit_image(src, (20, 20))
-        assert fit.image is not src
-        ImageDraw.Draw(src).rectangle([0, 0, 19, 19], fill=(0, 255, 0, 255))
-        assert fit.image.getpixel((5, 5)) == (255, 0, 0, 255)

test/test_adaptive_layout.py

@@ -436,19 +436,3 @@ class TestBasePluginIntegration:
                          MockCacheManager(), pm)
         assert plugin.layout.design_size == (64, 32)
         assert plugin.layout.scale == 2.0
-
-
-class TestFitCacheBound:
-    def test_fit_cache_is_lru_bounded(self, ctx):
-        """A plugin fitting changing text (live game clock, ticker) on a
-        24/7 service must not grow the fit cache without bound."""
-        for i in range(ctx._FIT_CACHE_MAX + 100):
-            ctx.fit_text(f"tick {i}", Region(0, 0, 100, 20))
-        assert len(ctx._fit_cache) <= ctx._FIT_CACHE_MAX
-
-    def test_lru_keeps_recent_entries_hot(self, ctx):
-        hot = ctx.fit_text("stay hot", Region(0, 0, 100, 20))
-        for i in range(ctx._FIT_CACHE_MAX - 1):
-            ctx.fit_text(f"cold {i}", Region(0, 0, 100, 20))
-            ctx.fit_text("stay hot", Region(0, 0, 100, 20))  # keep touching it
-        assert ctx.fit_text("stay hot", Region(0, 0, 100, 20)) is hot

test/test_cache_manager.py

@@ -400,61 +400,3 @@ class TestDiskCache:
         assert stats['fetch_count'] == 3
         assert stats['total_fetch_time'] == 1.8
         assert stats['average_fetch_time'] == pytest.approx(0.6, abs=0.01)
-
-
-class TestDiskCacheWriteEconomy:
-    """SD-card wear guards: identical payloads skip the disk, files are
-    compact, and TTL semantics survive the skip (see PR: fix/diskcache-sd-wear)."""
-
-    def test_identical_set_skips_rewrite(self, tmp_path):
-        import os
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"data": "v"})
-        path = cache.get_cache_path("k")
-        first = os.stat(path)
-        os.utime(path, (first.st_atime - 100, first.st_mtime - 100))  # age it
-        aged_mtime = os.stat(path).st_mtime
-        ino_before = os.stat(path).st_ino
-        cache.set("k", {"data": "v"})  # identical payload
-        after = os.stat(path)
-        # mtime refreshed (TTL for mtime-based records preserved)...
-        assert after.st_mtime > aged_mtime
-        # ...but the file was NOT rewritten (same inode: no replace happened)
-        assert after.st_ino == ino_before
-
-    def test_changed_data_rewrites(self, tmp_path):
-        import os
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"data": "v1"})
-        cache.set("k", {"data": "v2"})
-        assert cache.get("k") == {"data": "v2"}
-
-    def test_clear_resets_digest(self, tmp_path):
-        import os
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"data": "v"})
-        cache.clear("k")
-        assert cache.get("k") is None
-        cache.set("k", {"data": "v"})  # same payload after clear must WRITE
-        assert cache.get("k") == {"data": "v"}
-
-    def test_skip_self_heals_when_file_deleted_externally(self, tmp_path):
-        import os
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"data": "v"})
-        os.remove(cache.get_cache_path("k"))  # e.g. expiry cleanup
-        cache.set("k", {"data": "v"})  # digest matches but file is gone
-        assert cache.get("k") == {"data": "v"}
-
-    def test_files_are_compact_json(self, tmp_path):
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"a": 1, "b": [1, 2, 3]})
-        raw = open(cache.get_cache_path("k")).read()
-        assert "\n" not in raw.strip()  # no indent
-        assert cache.get("k") == {"a": 1, "b": [1, 2, 3]}
-
-    def test_datetime_round_trip_still_works(self, tmp_path):
-        from datetime import datetime
-        cache = DiskCache(cache_dir=str(tmp_path))
-        cache.set("k", {"when": datetime(2026, 7, 12, 10, 30)})
-        assert cache.get("k") == {"when": "2026-07-12T10:30:00"}

test/test_display_controller_vegas_tick.py

@@ -1,88 +0,0 @@
-"""
-Regression tests for DisplayController._tick_plugin_updates_for_vegas().
-
-PR #299 added logic to detect which plugins actually got fresh data on a
-scheduled-update tick and notify Vegas mode via
-vegas_coordinator.mark_plugin_updated(), so a live score change reaches the
-scroll within seconds instead of waiting for a full cycle. PR #330's
-multi-display sync refactor deleted this method (folding the callback back
-to the plain _tick_plugin_updates(), which reports nothing), silently
-orphaning VegasModeCoordinator.mark_plugin_updated() -- it has had zero
-callers since.
-"""
-
-from typing import Dict, List, Optional
-from unittest.mock import MagicMock
-
-from src.display_controller import DisplayController
-
-
-def _make_controller(updated: Optional[List[str]] = None, vegas_coordinator: Optional[MagicMock] = None) -> DisplayController:
-    dc = object.__new__(DisplayController)
-    dc.plugin_manager = MagicMock()
-    dc.plugin_manager.run_scheduled_updates_with_changes.return_value = list(updated or [])
-    dc.vegas_coordinator = vegas_coordinator
-    return dc
-
-
-class TestTickPluginUpdatesForVegas:
-    def test_marks_only_plugins_whose_timestamp_advanced(self):
-        vc = MagicMock()
-        dc = _make_controller(updated=["stock-news"], vegas_coordinator=vc)
-
-        dc._tick_plugin_updates_for_vegas()
-
-        vc.mark_plugin_updated.assert_called_once_with("stock-news")
-
-    def test_no_advance_marks_nothing(self):
-        vc = MagicMock()
-        dc = _make_controller(updated=[], vegas_coordinator=vc)
-
-        dc._tick_plugin_updates_for_vegas()
-
-        vc.mark_plugin_updated.assert_not_called()
-
-    def test_no_vegas_coordinator_does_not_raise(self):
-        dc = _make_controller(updated=["stock-news"], vegas_coordinator=None)
-
-        dc._tick_plugin_updates_for_vegas()  # must not raise
-
-    def test_mark_plugin_updated_exception_does_not_propagate(self):
-        """One plugin's mark_plugin_updated failing must not stop the tick
-        or crash the update loop it runs in."""
-        vc = MagicMock()
-        vc.mark_plugin_updated.side_effect = [RuntimeError("boom"), None]
-        dc = _make_controller(updated=["a", "b"], vegas_coordinator=vc)
-
-        dc._tick_plugin_updates_for_vegas()  # must not raise
-
-        assert vc.mark_plugin_updated.call_count == 2
-
-
-class TestVegasCoordinatorCallbackWiring:
-    def test_initialize_wires_vegas_aware_tick_as_update_callback(self):
-        """The Vegas coordinator must be given the Vegas-aware
-        _tick_plugin_updates_for_vegas as its update callback, not the plain
-        _tick_plugin_updates() -- that's the exact wiring PR #330 dropped."""
-        dc = object.__new__(DisplayController)
-        dc.config = {"display": {"vegas_scroll": {"enabled": True}}, "sync": {}}
-        dc.display_manager = MagicMock()
-        dc.plugin_manager = MagicMock()
-        dc.sync_manager = MagicMock()
-        dc._check_live_priority = MagicMock()
-        dc._check_vegas_interrupt = MagicMock(return_value=False)
-
-        fake_coordinator = MagicMock()
-
-        import src.display_controller as dc_module
-        original_imported = dc_module._vegas_mode_imported
-        original_class = dc_module.VegasModeCoordinator
-        try:
-            dc_module._vegas_mode_imported = True
-            dc_module.VegasModeCoordinator = MagicMock(return_value=fake_coordinator)
-            dc._initialize_vegas_mode()
-        finally:
-            dc_module._vegas_mode_imported = original_imported
-            dc_module.VegasModeCoordinator = original_class
-
-        fake_coordinator.set_update_callback.assert_called_once_with(dc._tick_plugin_updates_for_vegas)

test/test_snapshot_policy.py

@@ -1,93 +0,0 @@
-"""Tests for the snapshot write policy (src/common/snapshot_policy.py).
-
-The invariants that matter:
-- unchanged frames are NEVER re-encoded (the old code PNG-encoded identical
-  frames at 5 fps, 24/7)
-- the file mtime never goes stale enough to trip the health check's 60s
-  degraded threshold (api_v3 get_hardware_status)
-- a viewer gets full cadence; no viewer drops to the idle keepalive
-"""
-
-import os
-import sys
-
-import pytest
-
-sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
-
-from src.common.snapshot_policy import (  # noqa: E402
-    IDLE_INTERVAL,
-    TOUCH_INTERVAL,
-    VIEWER_INTERVAL,
-    SnapshotAction,
-    decide,
-)
-
-
-class TestViewerCadence:
-    def test_changed_frame_with_viewer_writes_at_full_rate(self):
-        assert decide(now=100.0, last_write_ts=100.0 - VIEWER_INTERVAL,
-                      last_touch_ts=0, viewer_fresh=True,
-                      frame_changed=True) is SnapshotAction.WRITE
-
-    def test_changed_frame_with_viewer_respects_min_interval(self):
-        assert decide(now=100.0, last_write_ts=100.0 - VIEWER_INTERVAL / 2,
-                      last_touch_ts=100.0, viewer_fresh=True,
-                      frame_changed=True) is SnapshotAction.SKIP
-
-    def test_unchanged_frame_with_viewer_never_writes(self):
-        """A static screen with a viewer must not burn PNG encodes."""
-        assert decide(now=100.0, last_write_ts=90.0, last_touch_ts=90.0,
-                      viewer_fresh=True,
-                      frame_changed=False) is SnapshotAction.SKIP
-
-
-class TestIdleCadence:
-    def test_changed_frame_without_viewer_waits_for_idle_interval(self):
-        assert decide(now=100.0, last_write_ts=100.0 - IDLE_INTERVAL / 2,
-                      last_touch_ts=100.0, viewer_fresh=False,
-                      frame_changed=True) is SnapshotAction.SKIP
-
-    def test_changed_frame_without_viewer_writes_at_idle_rate(self):
-        assert decide(now=100.0, last_write_ts=100.0 - IDLE_INTERVAL,
-                      last_touch_ts=0, viewer_fresh=False,
-                      frame_changed=True) is SnapshotAction.WRITE
-
-
-class TestHealthKeepalive:
-    def test_stale_mtime_gets_touched(self):
-        """Whatever else happens, mtime must be bumped within TOUCH_INTERVAL
-        so the health check (60s threshold) never reads the display as dead."""
-        assert decide(now=100.0, last_write_ts=100.0 - TOUCH_INTERVAL,
-                      last_touch_ts=100.0 - TOUCH_INTERVAL, viewer_fresh=False,
-                      frame_changed=False) is SnapshotAction.TOUCH
-
-    def test_touch_applies_with_viewer_too(self):
-        """Viewer watching a static screen: no writes, but health stays green."""
-        assert decide(now=100.0, last_write_ts=100.0 - TOUCH_INTERVAL - 1,
-                      last_touch_ts=100.0 - TOUCH_INTERVAL - 1, viewer_fresh=True,
-                      frame_changed=False) is SnapshotAction.TOUCH
-
-    def test_recent_touch_suppresses_another(self):
-        assert decide(now=100.0, last_write_ts=0.0,
-                      last_touch_ts=100.0 - TOUCH_INTERVAL / 2, viewer_fresh=False,
-                      frame_changed=False) is SnapshotAction.SKIP
-
-    def test_touch_interval_stays_under_health_threshold(self):
-        """api_v3's hardware status treats snapshot age >= 60s as degraded.
-        Keep a 2x margin so scheduling jitter can't trip it."""
-        assert TOUCH_INTERVAL <= 30
-
-    def test_worst_case_mtime_age_is_bounded(self):
-        """Simulate any interleaving: from any state, within one policy call
-        after TOUCH_INTERVAL elapses, mtime gets refreshed (WRITE or TOUCH)."""
-        for viewer in (True, False):
-            for changed in (True, False):
-                action = decide(now=1000.0, last_write_ts=900.0,
-                                last_touch_ts=900.0, viewer_fresh=viewer,
-                                frame_changed=changed)
-                assert action in (SnapshotAction.WRITE, SnapshotAction.TOUCH)
-
-
-if __name__ == "__main__":
-    sys.exit(pytest.main([__file__, "-v"]))

test/test_vegas_render_pipeline_recompose.py

@@ -1,72 +0,0 @@
-"""
-Regression tests for RenderPipeline.should_recompose()'s pending-updates check.
-
-PR #299 added a check so a plugin's live score/status change (a "pending
-update" in StreamManager) triggers a hot-swap within a few seconds instead
-of waiting for a full scroll cycle to complete. PR #330 (multi-display sync)
-refactored should_recompose() and dropped that check entirely -- not just
-gated behind the new sync-mode deferral it added, but removed outright, so
-even standalone (non-sync) installations silently lost live-refresh and fell
-back to waiting for full cycle boundaries (which, depending on
-min/max_cycle_duration, can be minutes).
-"""
-
-from unittest.mock import MagicMock
-
-from src.vegas_mode.config import VegasModeConfig
-from src.vegas_mode.render_pipeline import RenderPipeline
-
-
-class FakeDisplayManager:
-    width = 64
-    height = 32
-
-
-def _make_pipeline(sync_manager=None):
-    stream_manager = MagicMock()
-    stream_manager.get_buffer_status.return_value = {'staging_count': 0}
-    pipeline = RenderPipeline(VegasModeConfig(), FakeDisplayManager(), stream_manager)
-    pipeline.sync_manager = sync_manager
-    return pipeline, stream_manager
-
-
-class TestShouldRecompose:
-    def test_cycle_complete_always_recomposes(self):
-        pipeline, stream_manager = _make_pipeline()
-        pipeline._cycle_complete = True
-        stream_manager.has_pending_updates_for_visible_segments.return_value = False
-        assert pipeline.should_recompose() is True
-
-    def test_no_pending_updates_no_staging_does_not_recompose(self):
-        pipeline, stream_manager = _make_pipeline()
-        stream_manager.has_pending_updates_for_visible_segments.return_value = False
-        assert pipeline.should_recompose() is False
-
-    def test_pending_updates_on_visible_segment_triggers_recompose(self):
-        """The actual regression: a live-updated plugin currently in view
-        must trigger a recompose instead of waiting for cycle end."""
-        pipeline, stream_manager = _make_pipeline()
-        stream_manager.has_pending_updates_for_visible_segments.return_value = True
-        assert pipeline.should_recompose() is True
-
-    def test_staging_buffer_content_triggers_recompose(self):
-        pipeline, stream_manager = _make_pipeline()
-        stream_manager.get_buffer_status.return_value = {'staging_count': 1}
-        stream_manager.has_pending_updates_for_visible_segments.return_value = False
-        assert pipeline.should_recompose() is True
-
-    def test_sync_active_defers_pending_updates_to_cycle_boundary(self):
-        """Sync-mode deferral (PR #330's actual intent) must still hold:
-        pending updates alone must NOT trigger a mid-cycle hot-swap when a
-        follower display is attached, since that causes a visible
-        freeze+jump on the follower. This must keep working after
-        restoring the non-sync pending-updates check above."""
-        pipeline, stream_manager = _make_pipeline(sync_manager=MagicMock())
-        stream_manager.has_pending_updates_for_visible_segments.return_value = True
-        assert pipeline.should_recompose() is False
-
-    def test_sync_active_still_recomposes_on_cycle_complete(self):
-        pipeline, stream_manager = _make_pipeline(sync_manager=MagicMock())
-        pipeline._cycle_complete = True
-        stream_manager.has_pending_updates_for_visible_segments.return_value = True
-        assert pipeline.should_recompose() is True

web_interface/app.py

@@ -608,23 +608,9 @@ def display_preview_generator():
     import base64
     from PIL import Image
     import io
-
+    
     snapshot_path = "/tmp/led_matrix_preview.png"  # nosec B108 - fixed path matches display_manager; only read here
-    # Viewer marker: this generator only runs while the broadcaster has
-    # subscribers (it exits with no clients), so touching the marker each
-    # loop tells the DISPLAY service a browser is actually watching — it
-    # only pays for full-rate PNG snapshot encodes while this stays fresh
-    # (see src/common/snapshot_policy.py).
-    viewer_marker_path = "/tmp/led_matrix_preview_viewer"  # nosec B108 - fixed path matches display_manager
     last_modified = None
-
-    def _touch_viewer_marker():
-        try:
-            with open(viewer_marker_path, 'a'):
-                pass
-            os.utime(viewer_marker_path, None)
-        except OSError:
-            pass  # display side treats a missing marker as "no viewer"
     
     # Get display dimensions from config
     try:
@@ -641,7 +627,6 @@ def display_preview_generator():
     
     while True:
         try:
-            _touch_viewer_marker()
             # Check if snapshot file exists and has been modified
             if os.path.exists(snapshot_path):
                 current_modified = os.path.getmtime(snapshot_path)

web_interface/blueprints/api_v3.py

@@ -329,7 +329,6 @@ def save_schedule_config():
         }
 
         mode = data.get('mode', 'global')
-        schedule_config['mode'] = mode
 
         if mode == 'global':
             # Simple global schedule