fix(display): a non-numeric plugin duration no longer stops the display; narrow scroll strips no longer raise (#739)

* fix(display): a plugin duration that is not a number no longer stops the display

DisplayController._get_display_duration returned whatever the plugin's
get_display_duration() gave back. clock-simple, calendar and countdown
return their display_duration setting straight from config.json, so a
value saved as "20" or null reached _resolve_durations as a string or
None, and its `<= 0` check raised a TypeError. Nothing in the loop caught
it: run()'s outer handler logged "Unexpected error in display controller"
and cleanup() ended the service when that plugin's screen came up, and
systemd restarted it into the same crash.

The plugin's answer is now read as seconds: a finite number or a numeric
string is used (as BasePlugin.get_display_duration already accepts), a
number at or below zero still goes to _resolve_durations' 15 s rule, and
anything else -- None, a non-numeric string, a bool, NaN, infinity, or a
get_display_duration() that raises -- gets the 30 s a mode without a
plugin gets. The warning is logged once per plugin, not at every screen.

Tests: test/test_display_duration_not_a_number.py, including the real
run() on the run-loop harness, which returned at t=30 before the fix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(scroll): a strip narrower than the panel no longer raises on every frame

ScrollHelper._get_visible_portion_integer handled a frame that runs off
the end of the strip by copying the strip's tail and then the rest of the
frame from its head, which assumed the head was at least that wide. For a
strip narrower than the panel that raised "could not broadcast input
array" at every position, so get_visible_portion() never returned a frame
and the caller logged a traceback each frame. Vegas composes such a strip
(lead_in_width defaults to 0) when its content is narrower than the chain.

A wrapping frame is now taken column by column modulo the strip's width
(np.take, mode='wrap', into the reused frame buffer): the tail then the
head, as before, and a narrow strip repeated across the panel. The same
path takes a position before the start of the strip, whose [-n:m] slice
was empty and made frombytes raise; the integer and sub-pixel fast paths
now leave a negative start to it. A zero-width strip is still a black
frame.

Tests: test/test_scroll_helper_narrow_strip.py.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

src/common/scroll_helper.py

@@ -561,7 +561,7 @@ class ScrollHelper:
         width = self.display_width
         strip_width = self.cached_array.shape[1]
 
-        if start_x + width + 1 <= strip_width:
+        if 0 <= start_x and start_x + width + 1 <= strip_width:
             # Slice the backing array directly. Going via
             # _get_visible_portion_integer would build two PIL images only for
             # them to be converted straight back to arrays, which measured 15x
@@ -569,9 +569,10 @@ class ScrollHelper:
             near = self.cached_array[:, start_x:start_x + width]
             far = self.cached_array[:, start_x + 1:start_x + 1 + width]
         else:
-            # Close enough to the end that one of the slices wraps; let the
-            # integer path handle that and pay the conversion. Continuous mode
-            # extends the strip before reaching here, so this is the rare case.
+            # One of the slices wraps (close to the end, or a strip narrower
+            # than the panel); let the integer path handle that and pay the
+            # conversion. Continuous mode extends the strip before reaching
+            # here, so this is the rare case.
             near = np.asarray(
                 self._get_visible_portion_integer(start_x, start_x + width))
             far = np.asarray(
@@ -601,34 +602,33 @@ class ScrollHelper:
         _size = (self.display_width, self.display_height)
         img_w = self.cached_array.shape[1]
 
-        if end_x <= img_w:
+        if 0 <= start_x and end_x <= img_w:
             # Normal case: single contiguous slice (fastest path). tobytes()
             # on the column-slice view already returns C-order bytes, so
             # ascontiguousarray() first only added a second full-frame copy.
             return Image.frombytes(
                 'RGB', _size,
                 self.cached_array[:, start_x:end_x].tobytes())
+
+        # Ensure frame buffer is allocated for all non-simple paths
+        if self._frame_buffer is None or self._frame_buffer.shape != (self.display_height, self.display_width, 3):
+            self._frame_buffer = np.zeros((self.display_height, self.display_width, 3), dtype=np.uint8)
+
+        if img_w == 0:
+            self._frame_buffer[:] = 0
         else:
-            # Ensure frame buffer is allocated for all non-simple paths
-            if self._frame_buffer is None or self._frame_buffer.shape != (self.display_height, self.display_width, 3):
-                self._frame_buffer = np.zeros((self.display_height, self.display_width, 3), dtype=np.uint8)
+            # The frame runs off the strip, so it carries on from the head:
+            # frame column j is strip column (start_x + j) modulo the strip's
+            # width -- the tail and then the head, and a strip narrower than
+            # the panel repeated across it. Copying the tail and then the rest
+            # of the frame from the head assumed the head was that wide, and
+            # raised at every position for a strip narrower than the panel
+            # (Vegas composes one, with no lead-in, when its content is
+            # narrower than the chain).
+            np.take(self.cached_array, np.arange(start_x, end_x), axis=1,
+                    mode='wrap', out=self._frame_buffer)
 
-            width1 = img_w - start_x
-            if width1 > 0:
-                # Wrap-around: tail of image + head of image
-                self._frame_buffer[:, :width1] = self.cached_array[:, start_x:]
-                remaining_width = self.display_width - width1
-                self._frame_buffer[:, width1:] = self.cached_array[:, :remaining_width]
-            else:
-                # Edge case: start_x at or past image end — show from beginning,
-                # clamped to available width (scroll_position should wrap before
-                # reaching this state in normal operation).
-                available = min(self.display_width, img_w)
-                self._frame_buffer[:, :available] = self.cached_array[:, :available]
-                if available < self.display_width:
-                    self._frame_buffer[:, available:] = 0
-
-            return Image.frombytes('RGB', _size, self._frame_buffer.tobytes())
+        return Image.frombytes('RGB', _size, self._frame_buffer.tobytes())
     
     def calculate_dynamic_duration(self) -> int:
         """

src/display_controller.py

@@ -25,11 +25,12 @@ import os
 import inspect
 import signal
 import json
+import math
 import threading
 import types
 from collections import deque
 from contextlib import contextmanager
-from typing import Dict, Any, List, Optional, Callable, Set, Tuple
+from typing import Dict, Any, FrozenSet, List, Optional, Callable, Set, Tuple
 from datetime import datetime
 from concurrent.futures import ThreadPoolExecutor, as_completed  # pylint: disable=no-name-in-module
 import pytz
@@ -89,6 +90,19 @@ _MIN_INITIAL_UPDATE_TIMEOUT_SECONDS = 2.0
 DEFAULT_DYNAMIC_DURATION_CAP = 180.0
 
 
+def _finite_seconds(value: Any) -> Optional[float]:
+    """``value`` as seconds when it is a finite number or a numeric string,
+    else None. A bool is not a number here, though it is an int: True would
+    read as a one-second screen."""
+    if isinstance(value, bool):
+        return None
+    try:
+        seconds = float(value)
+    except (TypeError, ValueError, OverflowError):
+        return None
+    return seconds if math.isfinite(seconds) else None
+
+
 class _PluginReloadJob:
     """A ``plugin.reload`` whose slow half runs off the render thread.
 
@@ -1340,6 +1354,12 @@ class DisplayController:
                         "until one does", self.EMPTY_ROTATION_PAUSE)
         self._sleep_with_plugin_updates(self.EMPTY_ROTATION_PAUSE)
 
+    #: Plugins already warned about a display duration that is not a number,
+    #: so a bad setting logs once, not at every one of its screens. A
+    #: frozenset, replaced rather than mutated; class-level default for
+    #: controllers built without __init__ (tests).
+    _duration_warned: FrozenSet[str] = frozenset()
+
     def _get_display_duration(self, mode_key):
         """Seconds to show a mode: the Rotation & Durations page's value for it
         (display.display_durations), else the plugin's own duration.
@@ -1347,6 +1367,17 @@ class DisplayController:
         The saved value has to win. Every plugin inherits
         get_display_duration(), so checking the plugin first meant the page's
         values were never read.
+
+        The plugin's answer is checked here, not trusted. Several plugins
+        return their display_duration setting straight from config.json, so
+        one saved as "20" or null (the raw config editor, a hand edit) came
+        back as a string or None; _resolve_durations compared it with 0, and
+        the TypeError went past every handler in the loop and stopped the
+        display service, which systemd restarted into the same screen. A
+        numeric string counts, as in BasePlugin.get_display_duration; any
+        other value that is not a finite number, or a raise, gets the 30 s a
+        mode without a plugin gets. A number at or below zero is passed on:
+        _resolve_durations has its own rule for that.
         """
         display_durations = self.config.get('display', {}).get('display_durations', {}) or {}
         override = display_durations.get(mode_key)
@@ -1354,8 +1385,22 @@ class DisplayController:
             return float(override)
 
         plugin_instance = self.plugin_modes.get(mode_key)
-        if plugin_instance is not None and hasattr(plugin_instance, 'get_display_duration'):
-            return plugin_instance.get_display_duration()
+        if plugin_instance is None or not hasattr(plugin_instance, 'get_display_duration'):
+            return 30
+        try:
+            value = plugin_instance.get_display_duration()
+        except Exception as err:  # pylint: disable=broad-except
+            problem = f"get_display_duration() raised {type(err).__name__}: {err}"
+        else:
+            seconds = _finite_seconds(value)
+            if seconds is not None:
+                return seconds
+            problem = f"display duration {value!r} is not a number"
+        plugin_id = getattr(plugin_instance, 'plugin_id', None) or mode_key
+        if plugin_id not in self._duration_warned:
+            self._duration_warned = self._duration_warned | {plugin_id}
+            logger.warning("Plugin %s: %s; showing its modes for 30s (logged once)",
+                           plugin_id, problem)
         return 30
 
     def _get_global_dynamic_cap(self) -> Optional[float]: