fix(web): keep exception messages out of API responses (py/stack-trace-exposure)

CodeQL had ~40 open py/stack-trace-exposure alerts on main. Almost all
flowed through describe_exception(), which returned "TypeName: message"
(redacted, capped); the rest through _run_systemctl_command's str(err),
WiFiManager's `return False, str(e)`, unit_refresh's f-strings and two
str(e)/f"{err}" messages in api_v3/__init__.py.

describe_exception() now returns a reason code -- the type, plus the
errno symbol for an OSError ("OSError:EIO", "PermissionError:EACCES") --
and logs the redacted message itself. That keeps what #538 wanted (a
failing disk still says EIO in the response) without quoting paths,
URLs or library internals, and fixes every call site at once; the
test_no_api_v3_handler_discards_its_exception policy still holds.

Service results: _get_display_service_status returns active/returncode
only, and the on-demand start/stop `service` result keeps
returncode/active/started/status but drops systemctl stdout/stderr
(logged on failure). Nothing in web_interface/static, the templates or
the MQTT bridge reads those fields. The Starlark SIGKILL-restart error
no longer returns systemctl stderr as `details`.

WiFi, unit-refresh, config-save and plugin-removal failures now say
what failed with the reason code and point at the log. display.py is
untouched (draft #773 edits it).

Tests: test_api_v3_no_exception_text.py drives one route per affected
file with a marker in the exception message and asserts it never
reaches the body; all 13 fail on origin/main, and targeted mutations
(drop the service filter, put stderr back, str(e) in WiFiManager,
{e} in unit_refresh, {install_err} in system.py, message back in
describe_exception) each fail at least one. Tests that asserted the old
message-in-details contract now assert the reason code.

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

CHANGELOG.md

@@ -19,15 +19,15 @@ accepts both, but the store flags the old spelling as deprecated
 
 ## Unreleased
 
-### Tooling
-
-- `test/test_sports_helpers.py`'s parity tests pass again with
-  `LEDMATRIX_PLUGINS` set. The scoreboards deleted their copies of the
-  `sports_helpers` bodies and constants when they adopted `SportsHelpersMixin`
-  (ledmatrix-plugins #563/#564), and the 19 tests still expected them. A copy
-  that is gone now counts as adopted when the plugin imports
-  `src.common.sports_helpers`, as the stage 3/4 and game-over parity tests
-  already do; a copy that remains must still match.
+- Web API error responses no longer carry an exception's message (CodeQL
+  `py/stack-trace-exposure`). `describe_exception()` now returns a reason
+  code -- the exception type, plus the errno for an `OSError`
+  (`OSError:EIO`, `PermissionError:EACCES`) -- and logs the message
+  instead, so `details` still names the fault without quoting paths, URLs
+  or library internals. The display service status and the on-demand
+  start/stop `service` results keep `active`, `returncode` and `started`
+  but drop systemctl's `stdout`/`stderr`; WiFi, unit-refresh and
+  config-save failures say what failed and point at the log.
 
 ## 3.8.2
 

docs/ARCHITECTURE.md

@@ -143,9 +143,7 @@ loaded and when. Nothing else keeps plugin state:
 `DisplayController` right after it creates the `PluginManager`, writes the
 cache key `plugin_runtime_snapshot`: per plugin `loaded`, `state`, `error`
 (type, a redacted message of at most 200 characters, when, recoverable),
-`version`, `loaded_at` and `modes` (the display modes `DisplayController`
-registered -- `plugin.modes` when the plugin computes them, else the
-manifest's), plus `published_at`, `stale_after` and `running`.
+`version` and `loaded_at`, plus `published_at`, `stale_after` and `running`.
 The cache is on disk, usually the SD card, so it writes when something a
 reader sees changes -- throttled to once per 10 s -- and otherwise once a
 minute as a heartbeat. RUNNING, which every `update()` passes through, is
@@ -161,9 +159,6 @@ truth cannot leak into a response. `/api/v3/plugins/installed` returns
 `loaded`, `state`, `error_info`, `loaded_version` and `loaded_at` per
 plugin and `data.runtime` (`status`, `published_at`, `age_seconds`);
 `/api/v3/plugins/state` returns the same beside the desired state.
-`PluginCatalog.get_plugin_display_modes` and `find_plugin_for_mode` prefer a
-live view's `modes` to the manifest's `display_modes`, so `/display/modes`
-and on-demand see modes a plugin generates from its config (#668).
 
 **Reconciliation**
 ([`state_reconciliation.py`](../src/plugin_system/state_reconciliation.py))

docs/REST_API_REFERENCE.md

@@ -363,11 +363,9 @@ it. This is the list the force-display dialog offers.
 
 Send the reported `plugin_id` alongside `mode` when starting an on-demand
 display: `/display/on-demand/start` falls back to `find_plugin_for_mode` when
-`plugin_id` is omitted. While the display is running, this list and that
-lookup use the modes the display registered, including ones a plugin generates
-from its config (each installed Starlark app, each soccer `custom_leagues`
-entry). With the display stopped, or for a plugin it has not loaded, both see
-only the modes its manifest declares.
+`plugin_id` is omitted, and that lookup only sees modes declared in a static
+manifest — a plugin whose modes are generated (each installed Starlark app is
+one) returns 404 there.
 
 Triggers plugin discovery, which is otherwise lazy — so a caller that never
 opens the dashboard still gets the full list.

src/display_controller.py

@@ -4624,15 +4624,6 @@ class DisplayController:
             display_modes = [plugin_id]
         with self._plugin_modes_lock:
             self.plugin_display_modes[plugin_id] = list(display_modes)
-        # Into the runtime snapshot the web interface reads, so its mode
-        # lists and on-demand lookups see computed modes too (#668).
-        state_manager = getattr(self.plugin_manager, 'state_manager', None)
-        record_modes = getattr(state_manager, 'record_modes', None)
-        if callable(record_modes):
-            try:
-                record_modes(plugin_id, list(display_modes))
-            except Exception as e:  # reporting must never break registration
-                logger.debug("Could not record display modes for %s: %s", plugin_id, e)
 
         # Subscribe to config changes for per-plugin hot-reload. Bind plugin_id
         # and instance as defaults so each plugin's callback targets its own

src/plugin_system/plugin_catalog.py

@@ -15,8 +15,7 @@ reads through a catalog unchanged. It has nothing that runs a plugin: no
 ``load_plugin``, ``get_plugin`` or ``plugins``.
 
 Runtime state -- whether the display has a plugin loaded, its health, its
-errors -- is not here either, with one exception: given a ``runtime_source``,
-the mode lookups prefer the modes the running display registered. The display process publishes what it knows to
+errors -- is not here either. The display process publishes what it knows to
 the shared cache (health and resource metrics, the current mode, the error
 aggregator snapshot), and the web routes read those publications. What the
 display does not publish (which plugins it has loaded, its plugin state
@@ -27,9 +26,8 @@ See docs/ARCHITECTURE.md ("Web and display processes").
 
 import json
 import threading
-import time
 from pathlib import Path
-from typing import Any, Callable, Dict, List, Optional, Union, cast
+from typing import Any, Dict, List, Optional, Union, cast
 
 from src.common.permission_utils import (
     ensure_directory_permissions, get_plugin_dir_mode,
@@ -41,10 +39,6 @@ from src.plugin_system.plugin_dirs import (
 
 PathLike = Union[str, Path]
 
-#: How long one read of the display's runtime view answers mode lookups. A
-#: listing asks once per plugin; the cache copy is a file read each time.
-_RUNTIME_VIEW_TTL_SECONDS = 1.0
-
 
 class PluginCatalog:
     """Manifests, schemas, config and versions of the installed plugins.
@@ -55,17 +49,10 @@ class PluginCatalog:
     """
 
     def __init__(self, plugins_dir: PathLike, config_manager: Optional[Any] = None,
-                 schema_manager: Optional[Any] = None,
-                 runtime_source: Optional[Callable[[], Any]] = None) -> None:
+                 schema_manager: Optional[Any] = None) -> None:
         self.plugins_dir: Path = Path(plugins_dir)
         self.config_manager = config_manager
         self.schema_manager = schema_manager
-        # Returns the display's PluginRuntimeView
-        # (src/plugin_system/plugin_runtime.py). Its live view carries the
-        # modes the display registered, which the mode lookups below prefer
-        # to the manifest's. None: manifests only.
-        self.runtime_source = runtime_source
-        self._runtime_view_memo: Optional[tuple] = None
         self.logger = get_logger(__name__)
 
         # Guards plugin_manifests/plugin_directories: request threads read
@@ -185,67 +172,23 @@ class PluginCatalog:
             by_manifest=False)
         return str(plugin_dir) if plugin_dir is not None else None
 
-    def _runtime_view(self) -> Any:
-        """The display's runtime view, read at most once a second; None
-        without a source or when reading it fails."""
-        if self.runtime_source is None:
-            return None
-        now = time.monotonic()
-        memo = self._runtime_view_memo
-        if memo is not None and now - memo[0] < _RUNTIME_VIEW_TTL_SECONDS:
-            return memo[1]
-        try:
-            view = self.runtime_source()
-        except Exception as exc:  # a lookup must still answer from manifests
-            self.logger.debug("Could not read the display's runtime view: %s", exc)
-            view = None
-        self._runtime_view_memo = (now, view)
-        return view
-
-    def _live_display_modes(self, plugin_id: str) -> Optional[List[str]]:
-        """The modes the running display registered for ``plugin_id``, or None."""
-        view = self._runtime_view()
-        if view is None:
-            return None
-        try:
-            modes = view.display_modes(plugin_id)
-        except Exception as exc:  # includes a source returning something else
-            self.logger.debug("Could not read display modes for %s: %s", plugin_id, exc)
-            return None
-        return list(modes) if isinstance(modes, list) and modes else None
-
     def get_plugin_display_modes(self, plugin_id: str) -> List[str]:
-        """The modes the display registered for the plugin, else the
-        manifest's ``display_modes``, else [].
+        """The manifest's ``display_modes``, or [].
 
-        A plugin may compute its modes at run time (``plugin.modes``): each
-        league soccer-scoreboard's ``custom_leagues`` adds is a mode no
-        manifest can list ahead of time (#668). The running display
-        publishes what it registered, and that wins while the display is
-        live and has the plugin loaded. Otherwise -- display stopped, plugin
-        disabled -- the declared list is the best answer there is.
+        What the display actually rotates can differ: a plugin may compute
+        its modes at run time (``plugin.modes``). This is the declared list.
         """
-        live = self._live_display_modes(plugin_id)
-        if live is not None:
-            return live
         with self._lock:
             manifest = self.plugin_manifests.get(plugin_id)
         modes = (manifest or {}).get('display_modes', [])
         return list(modes) if isinstance(modes, list) else []
 
     def find_plugin_for_mode(self, mode: str) -> Optional[str]:
-        """The plugin that registered ``mode`` on the running display, else
-        the one whose manifest declares it (case-insensitive both ways)."""
+        """The plugin whose manifest declares ``mode`` (case-insensitive)."""
         wanted = mode.strip().lower()
         with self._lock:
             manifests = dict(self.plugin_manifests)
-        for plugin_id in manifests:
-            live = self._live_display_modes(plugin_id)
-            if live and any(m.lower() == wanted for m in live):
-                return plugin_id
         for plugin_id, manifest in manifests.items():
-            if self._live_display_modes(plugin_id):
-                continue  # the display's list is the truth for this plugin
             modes = manifest.get('display_modes')
             if isinstance(modes, list) and any(
                     isinstance(m, str) and m.lower() == wanted for m in modes):

src/plugin_system/plugin_runtime.py

@@ -56,7 +56,7 @@ import os
 import threading
 import time
 from dataclasses import dataclass, field, replace
-from typing import Any, Callable, Dict, List, Optional
+from typing import Any, Callable, Dict, Optional
 
 from src import display_watchdog
 from src.logging_config import get_logger
@@ -100,9 +100,6 @@ _ERROR_MESSAGE_CHARS = 200
 _ERROR_TYPE_CHARS = 80
 _ID_CHARS = 100
 _VERSION_CHARS = 40
-#: Bounds on a plugin's published ``modes``: a plugin computes them, so a
-#: runaway list must not bloat a file written to the SD card.
-_MAX_MODES = 200
 
 #: Reader statuses. Only LIVE carries runtime facts.
 LIVE = "live"
@@ -157,15 +154,6 @@ def summarize_error(error_info: Optional[Dict[str, Any]]) -> Optional[Dict[str,
     }
 
 
-def _published_modes(modes: Any) -> Optional[List[str]]:
-    """The registered display modes as a snapshot carries them, or None."""
-    if not isinstance(modes, list):
-        return None
-    # A name is a key the display matches exactly: drop one too long to
-    # carry whole rather than clip it into a different name.
-    return [m for m in modes if isinstance(m, str) and len(m) <= _ID_CHARS][:_MAX_MODES]
-
-
 def build_runtime_snapshot(state_manager: Any, *, started_at: float,
                            now: Optional[float] = None,
                            running: bool = True,
@@ -185,7 +173,6 @@ def build_runtime_snapshot(state_manager: Any, *, started_at: float,
                 "error": summarize_error(record.get("error_info")),
                 "version": _clip(version, _VERSION_CHARS) if version else None,
                 "loaded_at": _epoch(record.get("loaded_at")),
-                "modes": _published_modes(record.get("modes")),
             }
     return {
         "schema": SNAPSHOT_SCHEMA,
@@ -429,21 +416,6 @@ class PluginRuntimeView:
             "loaded_at": record.get("loaded_at"),
         }
 
-    def display_modes(self, plugin_id: str) -> Optional[List[str]]:
-        """The display modes the display registered for ``plugin_id``: what
-        it rotates and accepts on-demand, including modes a plugin computes
-        from its config. None unless the view is live and the plugin is
-        loaded with its modes registered -- the caller then falls back to
-        the manifest's ``display_modes``."""
-        if not self.live:
-            return None
-        record = self.plugins.get(plugin_id)
-        modes = record.get("modes") if isinstance(record, dict) else None
-        if not isinstance(modes, list):
-            return None
-        modes = [m for m in modes if isinstance(m, str)]
-        return modes or None
-
     def describe(self) -> Dict[str, Any]:
         """The view's own status, for a response to carry beside the facts."""
         return {

src/plugin_system/plugin_state.py

@@ -10,7 +10,7 @@ snapshot ``plugin_runtime.PluginRuntimePublisher`` publishes from it.
 import threading
 import time
 from enum import Enum
-from typing import Any, Dict, List, Optional
+from typing import Optional, Dict, Any
 from datetime import datetime
 import logging
 
@@ -231,26 +231,6 @@ class PluginStateManager:
             }
             self._note_change()
 
-    def record_modes(self, plugin_id: str, modes: List[str]) -> None:
-        """Record the display modes the display registered for ``plugin_id``.
-
-        Called by the DisplayController each time it registers the plugin.
-        These are the modes it actually rotates and accepts on-demand --
-        ``plugin.modes`` when the plugin computes them (a soccer league the
-        user added under ``custom_leagues``), else the manifest's list -- and
-        the web interface has no other way to learn them (#668). Kept on the
-        loaded record, so an unload or a reload's fresh record_loaded()
-        forgets them until the plugin is registered again.
-        """
-        with self._lock:
-            loaded = self._loaded.get(plugin_id)
-            if loaded is None:
-                return
-            modes = [str(m) for m in modes]
-            if loaded.get('modes') != modes:
-                loaded['modes'] = modes
-                self._note_change()
-
     def record_unloaded(self, plugin_id: str) -> None:
         """Forget the loaded record alone, keeping state and error info: for
         an unload that failed after the instance was already dropped."""
@@ -263,8 +243,7 @@ class PluginStateManager:
         section so a concurrent load or unload is seen whole or not at all.
 
         Per plugin: ``state`` (published_state()'s value), ``loaded``,
-        ``version``, ``loaded_at`` and ``modes`` (None unless loaded; ``modes``
-        also None until the display registers it) and ``error_info``
+        ``version`` and ``loaded_at`` (None unless loaded) and ``error_info``
         (a copy, or None).
         """
         with self._lock:
@@ -278,7 +257,6 @@ class PluginStateManager:
                     'loaded': loaded is not None,
                     'version': loaded['version'] if loaded else None,
                     'loaded_at': loaded['loaded_at'] if loaded else None,
-                    'modes': list(loaded['modes']) if loaded and 'modes' in loaded else None,
                     'error_info': dict(info) if info is not None else None,
                 }
             return records

src/web_interface/error_handler.py

@@ -4,6 +4,7 @@ Centralized error handling for web interface.
 Provides helpers for consistent error responses across API endpoints.
 """
 
+import errno
 from typing import Any, Optional
 from flask import jsonify
 
@@ -20,10 +21,9 @@ logger = get_logger(__name__)
 _MAX_DETAIL_LENGTH = 400
 
 
-def describe_exception(exc: BaseException,
-                       max_length: int = _MAX_DETAIL_LENGTH) -> str:
+def describe_exception(exc: BaseException) -> str:
     """
-    One-line, safe-to-return description of an exception.
+    Machine-readable reason code for an exception, safe to return over HTTP.
 
     The generic "an error occurred; see logs for details" tells a user nothing
     and, when the failure is bad enough, the logs are unreachable too: a device
@@ -31,20 +31,24 @@ def describe_exception(exc: BaseException,
     *including* the log viewer, because journalctl could not be executed. The
     underlying `[Errno 5] Input/output error` named the fault immediately.
 
-    Returns "TypeName: message", credentials redacted and length capped. The
-    type alone is worth carrying -- a bare PermissionError says more than any
-    generic sentence.
+    So the type and errno still go back -- "OSError:EIO", "PermissionError:
+    EACCES", "TimeoutExpired" -- but never the exception's message, which can
+    quote paths, URLs, credentials or a library's internals (CodeQL
+    py/stack-trace-exposure). The message is logged here instead, so every
+    reason code a client sees has its full text in the log.
 
     Args:
         exc: The exception to describe
-        max_length: Truncate beyond this many characters
 
     Returns:
-        A single-line description, never empty
+        "TypeName" or "TypeName:ERRNO", never empty
     """
-    message = str(exc).strip()
-    text = f"{type(exc).__name__}: {message}" if message else type(exc).__name__
-    return redact_text(text, max_length)
+    code = type(exc).__name__
+    exc_errno = getattr(exc, 'errno', None)
+    if isinstance(exc_errno, int) and exc_errno in errno.errorcode:
+        code = f"{code}:{errno.errorcode[exc_errno]}"
+    logger.warning("Error reported to the client as %s: %s", code, redact_text(str(exc)))
+    return code
 
 
 def redact_text(text: str, max_length: int = _MAX_DETAIL_LENGTH) -> str:

src/wifi_manager.py

@@ -1369,7 +1369,7 @@ class WiFiManager:
                         self.enable_ap_mode(force=True)
                     except Exception as ap_error:  # nosec B110 - last-resort; do not re-raise, but log for debugging
                         logger.error("Last-resort AP mode enable failed in recovery path: %s", ap_error, exc_info=True)
-            return False, str(e)
+            return False, f"Connection failed ({type(e).__name__}); see logs for details"
     
     def _failsafe_ap(self, enabled_msg: str, failed_msg: str) -> Tuple[bool, str]:
         """Force the setup AP up after a connect that left no working network,
@@ -1585,7 +1585,7 @@ class WiFiManager:
         except Exception as e:
             logger.error(f"Error connecting with nmcli: {e}")
             self._show_led_message("Connection error", duration=5)
-            return False, str(e)
+            return False, f"Connection failed ({type(e).__name__}); see logs for details"
 
     # 802.11 caps an SSID at 32 octets. Control characters cannot appear in a
     # real one, and a leading "-" would be read by nmcli as an option rather
@@ -1725,7 +1725,7 @@ class WiFiManager:
                 return False, "nmcli is required to disconnect from WiFi"
         except Exception as e:
             logger.error(f"Error disconnecting from WiFi: {e}")
-            return False, str(e)
+            return False, f"Disconnect failed ({type(e).__name__}); see logs for details"
     
     def _ensure_wifi_radio_enabled(self, max_retries: int = 3) -> bool:
         """
@@ -2004,7 +2004,7 @@ class WiFiManager:
             return False, "No WiFi tools available (nmcli, hostapd, or dnsmasq required)"
         except Exception as e:
             logger.error(f"Error in enable_ap_mode: {e}")
-            return False, str(e)
+            return False, f"Could not enable AP mode ({type(e).__name__}); see logs for details"
     
     def _mark_forced(self) -> None:
         """Record that AP mode was forced on, so the periodic check leaves it
@@ -2099,10 +2099,10 @@ class WiFiManager:
                 return True, "AP mode enabled"
             except Exception as e:
                 logger.error(f"Error starting AP services: {e}")
-                return False, str(e)
+                return False, f"Could not enable AP mode ({type(e).__name__}); see logs for details"
         except Exception as e:
             logger.error(f"Error enabling AP mode: {e}")
-            return False, str(e)
+            return False, f"Could not enable AP mode ({type(e).__name__}); see logs for details"
     
     def _enable_ap_mode_nmcli_hotspot(self) -> Tuple[bool, str]:
         """
@@ -2227,7 +2227,7 @@ class WiFiManager:
             logger.error(f"Error starting AP mode with nmcli: {e}")
             self._remove_nm_dnsmasq_captive_conf()
             self._show_led_message("Setup mode error", duration=5)
-            return False, str(e)
+            return False, f"Could not enable AP mode ({type(e).__name__}); see logs for details"
     
     def _get_ap_status_nmcli(self) -> Dict:
         """
@@ -2409,10 +2409,10 @@ class WiFiManager:
                 return True, "AP mode disabled"
             except Exception as e:
                 logger.error(f"Error stopping AP services: {e}")
-                return False, str(e)
+                return False, f"Could not disable AP mode ({type(e).__name__}); see logs for details"
         except Exception as e:
             logger.error(f"Error disabling AP mode: {e}")
-            return False, str(e)
+            return False, f"Could not disable AP mode ({type(e).__name__}); see logs for details"
     
     def _create_hostapd_config(self):
         """Create hostapd configuration file"""

test/test_api_v3_display_modes.py

@@ -7,7 +7,7 @@ manifest.json off disk and reimplemented PluginManager's own fallbacks.
 """
 
 import json
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock
 
 import pytest
 
@@ -147,7 +147,8 @@ class TestOneBadConfigSectionDoesNotBlankTheList:
             side_effect=RuntimeError("disk is gone"))
         resp = api_v3_client.get('/api/v3/display/modes')
         assert resp.status_code == 500
-        assert 'disk is gone' in resp.get_json()['details']
+        assert resp.get_json()['details'] == 'RuntimeError'
+        assert 'disk is gone' not in json.dumps(resp.get_json())
 
     def test_credentials_in_the_exception_are_redacted(self, api_v3_module, api_v3_client):
         """describe_exception is what makes returning detail safe."""
@@ -155,14 +156,3 @@ class TestOneBadConfigSectionDoesNotBlankTheList:
             side_effect=RuntimeError("GET https://x/y?api_key=SEC123 failed"))
         body = api_v3_client.get('/api/v3/display/modes').get_json()
         assert 'SEC123' not in json.dumps(body)
-
-
-class TestOnDemandUsesTheRegisteredSpelling:
-    def test_a_mode_differing_in_case_is_sent_as_registered(self, client):
-        with patch('web_interface.blueprints.api_v3.display._deliver_on_demand',
-                   return_value=('socket', None)) as deliver:
-            response = client.post('/api/v3/display/on-demand/start',
-                                   json={'plugin_id': 'football-scoreboard',
-                                         'mode': 'NFL_LIVE', 'start_service': False})
-        assert response.status_code == 200, response.get_json()
-        assert deliver.call_args.args[0]['mode'] == 'nfl_live'

test/test_api_v3_no_exception_text.py

@@ -0,0 +1,147 @@
+"""No API response carries an exception's message (CodeQL py/stack-trace-exposure).
+
+One representative route per file that had open alerts. Each forces a failure
+whose message holds a marker and asserts the marker is nowhere in the body:
+the message goes to the log, the client gets a fixed message plus a reason
+code (describe_exception: the type, and the errno for an OSError).
+"""
+
+import json
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from test._api_v3_test_helpers import api_v3_client, api_v3_module  # noqa: F401,E402
+
+LEAK = "LEAKED-/home/pi/secret token=abc123"
+API = "web_interface.blueprints.api_v3"
+
+
+def _assert_no_leak(response):
+    body = response.get_data(as_text=True)
+    assert "LEAKED" not in body, body
+    assert "abc123" not in body, body
+    return json.loads(body)
+
+
+def test_display_service_status_drops_systemctl_output(api_v3_module, api_v3_client,
+                                                      monkeypatch):
+    """display.py: the on-demand routes return the service status verbatim."""
+    api_v3_module.api_v3.cache_manager.get.return_value = None
+    monkeypatch.setattr(f"{API}.display.display_state.read_state", lambda: None)
+    with patch(f"{API}.subprocess.run", side_effect=OSError(13, LEAK)):
+        body = _assert_no_leak(api_v3_client.get("/api/v3/display/on-demand/status"))
+    assert body["data"]["service"] == {"active": False, "returncode": -1}
+
+
+@pytest.mark.parametrize("helper", ["_ensure_display_service_running",
+                                    "_stop_display_service"])
+def test_service_results_keep_returncode_but_not_output(api_v3_module, helper):
+    """display.py start/stop: returncode/active/started stay, stdout/stderr go."""
+    failed = MagicMock(returncode=1, stdout=LEAK, stderr=LEAK)
+    with patch(f"{API}.subprocess.run", return_value=failed):
+        result = getattr(api_v3_module, helper)()
+    assert "LEAKED" not in json.dumps(result)
+    assert result["returncode"] == 1 and result["active"] is False
+    assert "stdout" not in result and "stderr" not in result
+
+
+def test_wifi_connect_failure(api_v3_client):
+    """wifi.py: a raising connect, and the attempt /wifi/status reports after."""
+    with patch("src.wifi_manager.WiFiManager") as cls:
+        cls.return_value._is_ap_mode_active.return_value = False
+        cls.return_value.connect_to_network.side_effect = RuntimeError(LEAK)
+        body = _assert_no_leak(api_v3_client.post(
+            "/api/v3/wifi/connect", json={"ssid": "HomeNet", "password": "pw"}))
+        assert body["details"] == "RuntimeError"
+        cls.return_value.get_wifi_status.return_value = MagicMock(
+            connected=False, ssid=None, ip_address=None, signal=0, ap_mode_active=False)
+        cls.return_value.config = {}
+        status = _assert_no_leak(api_v3_client.get("/api/v3/wifi/status"))
+    assert status["data"]["last_connect_attempt"]["message"] == (
+        "Failed to connect to network (RuntimeError)")
+
+
+def test_wifi_manager_messages_carry_no_exception_text():
+    """src/wifi_manager.py: its (success, message) is what the wifi routes return."""
+    from src.wifi_manager import WiFiManager
+    manager = WiFiManager.__new__(WiFiManager)  # no __init__: no host access
+    manager.get_wifi_status = MagicMock(side_effect=OSError(5, LEAK))
+    success, message = manager.disconnect_from_network()
+    assert success is False
+    assert "LEAKED" not in message and "OSError" in message
+
+
+def test_system_action_exception(api_v3_client):
+    """system.py: execute_system_action's catch-all."""
+    with patch("subprocess.run", side_effect=OSError(5, LEAK)):
+        body = _assert_no_leak(api_v3_client.post(
+            "/api/v3/system/action", json={"action": "stop_display"}))
+    assert body["details"] == "OSError:EIO"
+
+
+def test_calendar_registration_failure(api_v3_client, tmp_path, monkeypatch):
+    """plugin_calendar.py: the auth script could not be run."""
+    plugin_dir = tmp_path / "calendar"
+    plugin_dir.mkdir()
+    (plugin_dir / "credentials.json").write_text("{}", encoding="utf-8")
+    (plugin_dir / "calendar_registration.py").write_text("", encoding="utf-8")
+    monkeypatch.setattr(f"{API}._calendar_plugin_dir", lambda: plugin_dir)
+    with patch(f"{API}.subprocess.run", side_effect=OSError(13, LEAK)):
+        body = _assert_no_leak(api_v3_client.post(
+            "/api/v3/plugins/calendar/authenticate", json={"code": "x"}))
+    assert "EACCES" in body["message"]
+
+
+def test_health_failure(api_v3_client, monkeypatch):
+    """misc.py: get_health's catch-all."""
+    def boom():
+        raise RuntimeError(LEAK)
+    monkeypatch.setattr(f"{API}.misc._get_display_service_status", boom)
+    body = _assert_no_leak(api_v3_client.get("/api/v3/health"))
+    assert body["details"] == "RuntimeError"
+
+
+def test_config_route_failure(api_v3_module, api_v3_client):
+    """error_handler.py: create_error_response, as config.py's routes use it."""
+    api_v3_module.api_v3.config_manager.load_config.side_effect = RuntimeError(LEAK)
+    body = _assert_no_leak(api_v3_client.get("/api/v3/config/schedule"))
+    assert body["details"] == "RuntimeError"
+
+
+def test_plugin_route_failure(api_v3_module, api_v3_client):
+    """plugins.py: an unhandled error in a plugin route."""
+    api_v3_module.api_v3.plugin_catalog.get_all_plugin_info.side_effect = RuntimeError(LEAK)
+    body = _assert_no_leak(api_v3_client.get("/api/v3/plugins/installed"))
+    assert body["details"] == "RuntimeError"
+
+
+def test_starlark_route_failure(api_v3_client):
+    """starlark.py: one of its catch-alls."""
+    with patch(f"{API}._get_starlark_plugin", side_effect=RuntimeError(LEAK)):
+        body = _assert_no_leak(api_v3_client.get("/api/v3/starlark/status"))
+    assert body["details"] == "RuntimeError"
+
+
+def test_unit_refresh_failure(monkeypatch):
+    """system.py git_pull: perform_core_update appends unit_refresh's message."""
+    from web_interface import unit_refresh
+
+    def boom(*_a, **_k):
+        raise RuntimeError(LEAK)
+    monkeypatch.setattr(unit_refresh, "stale_units", boom)
+    result = unit_refresh.refresh_after_update()
+    assert result["status"] == unit_refresh.FAILED
+    assert "LEAKED" not in result["message"]
+
+
+def test_install_base_requirements_failure(api_v3_client):
+    """system.py: a pip install that could not start, in the action's output."""
+    with patch(f"{API}.system._pip_install_requirements", side_effect=OSError(5, LEAK)):
+        body = _assert_no_leak(api_v3_client.post(
+            "/api/v3/system/action", json={"action": "install_base_requirements"}))
+    assert "Failed: OSError:EIO" in body["output"]

test/test_api_v3_registry_endpoints.py

@@ -95,9 +95,10 @@ class TestRefreshPluginStore:
             RuntimeError("failed at /home/user/LEDMatrix/src/secret.py line 42"))
         body = api_v3_client.post(self.URL, json={}).get_json()
         assert "Traceback" not in str(body)
-        # `details` is describe_exception output: one line, type-named,
-        # credential-redacted. It may quote the message, but never a stack.
-        assert body["details"].startswith("RuntimeError:")
+        # `details` is describe_exception output: the type, never the
+        # message or a stack.
+        assert body["details"] == "RuntimeError"
+        assert "secret.py" not in str(body)
         assert "\n" not in body["details"]
 
 

test/test_live_display_modes.py

@@ -1,265 +0,0 @@
-"""The web interface sees the display modes the display actually registered (#668).
-
-A plugin may compute its modes from its config: soccer-scoreboard registers
-``soccer_<league>_live/recent/upcoming`` for every league the user adds under
-``custom_leagues``, and no manifest can list those ahead of time. The display
-always rotated them -- DisplayController._register_loaded_plugin prefers
-``plugin.modes`` -- but the web process reads plugins as files, so its mode
-listing (/display/modes, the on-demand dialog) and find_plugin_for_mode
-(/display/on-demand/start with a mode and no plugin_id) saw only manifests.
-
-The display now records each plugin's registered modes in its plugin state,
-the runtime snapshot carries them, and PluginCatalog prefers them while the
-snapshot is live, falling back to the manifest when it is not.
-"""
-import json
-import sys
-from pathlib import Path
-from unittest.mock import MagicMock
-
-import pytest
-
-sys.path.insert(0, str(Path(__file__).parent.parent))
-
-from src.cache_manager import CacheManager  # noqa: E402
-from src.plugin_system import plugin_runtime as rt  # noqa: E402
-from src.plugin_system.plugin_catalog import PluginCatalog  # noqa: E402
-from src.plugin_system.plugin_runtime import (  # noqa: E402
-    PluginRuntimePublisher, build_runtime_snapshot, read_plugin_runtime,
-    view_from_snapshot,
-)
-from src.plugin_system.plugin_state import PluginState, PluginStateManager  # noqa: E402
-from test._api_v3_test_helpers import api_v3_client, api_v3_module  # noqa: F401,E402
-
-DECLARED = ["soccer_eng.1_live", "soccer_eng.1_recent", "soccer_eng.1_upcoming"]
-CUSTOM = ["soccer_sco.1_live", "soccer_sco.1_recent", "soccer_sco.1_upcoming"]
-REGISTERED = DECLARED + CUSTOM
-
-
-def _loaded_states(modes=None):
-    states = PluginStateManager()
-    states.set_state("soccer-scoreboard", PluginState.ENABLED)
-    states.record_loaded("soccer-scoreboard", "2.24.1")
-    if modes is not None:
-        states.record_modes("soccer-scoreboard", modes)
-    return states
-
-
-@pytest.fixture
-def shared_cache(tmp_path, monkeypatch):
-    """Two cache managers over one directory: the display's and the web's."""
-    monkeypatch.setattr(CacheManager, "_get_writable_cache_dir",
-                        lambda self: str(tmp_path / "cache"))
-    (tmp_path / "cache").mkdir()
-    display_cache, web_cache = CacheManager(), CacheManager()
-    yield display_cache, web_cache
-    display_cache.stop_cleanup_thread()
-    web_cache.stop_cleanup_thread()
-
-
-@pytest.fixture
-def plugins_dir(tmp_path):
-    root = tmp_path / "plugins"
-    for plugin_id, modes in (("soccer-scoreboard", DECLARED), ("clock-simple", ["clock"])):
-        (root / plugin_id).mkdir(parents=True)
-        (root / plugin_id / "manifest.json").write_text(json.dumps({
-            "id": plugin_id, "name": plugin_id, "version": "1.0.0",
-            "class_name": "P", "display_modes": modes}), encoding="utf-8")
-    return root
-
-
-# --- The display records what it registered ---------------------------------
-
-class TestStateManagerRecordsModes:
-    def test_runtime_records_carry_them(self):
-        assert _loaded_states(REGISTERED).runtime_records()[
-            "soccer-scoreboard"]["modes"] == REGISTERED
-
-    def test_none_until_registered(self):
-        assert _loaded_states().runtime_records()["soccer-scoreboard"]["modes"] is None
-
-    def test_a_new_list_is_a_change_the_same_one_is_not(self):
-        """change_count drives the publisher: re-registering an unchanged
-        plugin must not cost an SD-card write."""
-        states = _loaded_states(DECLARED)
-        before = states.change_count
-        states.record_modes("soccer-scoreboard", list(DECLARED))
-        assert states.change_count == before
-        states.record_modes("soccer-scoreboard", REGISTERED)
-        assert states.change_count == before + 1
-
-    def test_ignored_for_a_plugin_that_is_not_loaded(self):
-        states = PluginStateManager()
-        states.record_modes("ghost", ["ghost"])
-        assert "ghost" not in states.runtime_records()
-
-    def test_unload_forgets_them(self):
-        states = _loaded_states(REGISTERED)
-        states.clear_state("soccer-scoreboard")
-        assert "soccer-scoreboard" not in states.runtime_records()
-
-    def test_a_reload_starts_without_them_until_registered_again(self):
-        states = _loaded_states(REGISTERED)
-        states.record_loaded("soccer-scoreboard", "2.25.0")
-        assert states.runtime_records()["soccer-scoreboard"]["modes"] is None
-
-
-class TestControllerRecordsOnRegistration:
-    def test_plugin_modes_reach_the_state_manager(self, test_display_controller):
-        """_register_loaded_plugin is the one path every load, enable and
-        reload goes through."""
-        c = test_display_controller
-        states = _loaded_states()
-        plugin = MagicMock()
-        plugin.modes = list(REGISTERED)
-        c.plugin_manager.state_manager = states
-        c.plugin_manager.get_plugin = MagicMock(return_value=plugin)
-        c.plugin_manager.plugin_manifests = {"soccer-scoreboard": {"display_modes": DECLARED}}
-
-        c._register_loaded_plugin("soccer-scoreboard")
-
-        assert states.runtime_records()["soccer-scoreboard"]["modes"] == REGISTERED
-
-    def test_a_failing_state_manager_does_not_break_registration(self, test_display_controller):
-        c = test_display_controller
-        plugin = MagicMock()
-        plugin.modes = ["clock"]
-        c.plugin_manager.state_manager.record_modes = MagicMock(side_effect=RuntimeError("x"))
-        c.plugin_manager.get_plugin = MagicMock(return_value=plugin)
-        c.plugin_manager.plugin_manifests = {}
-
-        assert c._register_loaded_plugin("clock-simple") == ["clock"]
-        assert c.mode_to_plugin_id["clock"] == "clock-simple"
-
-
-# --- The snapshot carries them; only a live view reports them ---------------
-
-class TestSnapshotAndView:
-    NOW = 1_800_000_000.0
-
-    def _view(self, states, running=True, published_at=None):
-        snapshot = build_runtime_snapshot(states, started_at=1.0, now=self.NOW,
-                                          running=running)
-        if published_at is not None:
-            snapshot["published_at"] = published_at
-        return view_from_snapshot(snapshot, now=self.NOW)
-
-    def test_live_view_reports_the_registered_modes(self):
-        assert self._view(_loaded_states(REGISTERED)).display_modes(
-            "soccer-scoreboard") == REGISTERED
-
-    def test_stale_and_stopped_views_report_nothing(self):
-        states = _loaded_states(REGISTERED)
-        assert self._view(states, published_at=self.NOW - 10_000).display_modes(
-            "soccer-scoreboard") is None
-        assert self._view(states, running=False).display_modes("soccer-scoreboard") is None
-
-    def test_unregistered_or_unknown_plugins_report_nothing(self):
-        view = self._view(_loaded_states())
-        assert view.display_modes("soccer-scoreboard") is None
-        assert view.display_modes("not-loaded") is None
-
-    def test_a_runaway_list_is_bounded(self):
-        modes = [f"m{i}" for i in range(1000)] + ["x" * 500]
-        snapshot = build_runtime_snapshot(_loaded_states(modes), started_at=1.0, now=self.NOW)
-        published = snapshot["plugins"]["soccer-scoreboard"]["modes"]
-        assert len(published) == rt._MAX_MODES
-
-    def test_a_mode_name_is_kept_whole_or_dropped(self):
-        long_mode = "x" * (rt._ID_CHARS + 1)
-        snapshot = build_runtime_snapshot(_loaded_states(["ok", long_mode]),
-                                          started_at=1.0, now=self.NOW)
-        assert snapshot["plugins"]["soccer-scoreboard"]["modes"] == ["ok"]
-
-    def test_non_strings_from_a_hand_made_snapshot_are_dropped(self):
-        snapshot = {"schema": rt.SNAPSHOT_SCHEMA, "running": True,
-                    "published_at": self.NOW, "plugins": {
-                        "p": {"loaded": True, "modes": ["a", 3, None]}}}
-        assert view_from_snapshot(snapshot, now=self.NOW).display_modes("p") == ["a"]
-
-
-# --- The web's catalog prefers them -------------------------------------------
-
-class TestCatalog:
-    def _catalog(self, plugins_dir, web_cache):
-        catalog = PluginCatalog(plugins_dir,
-                                runtime_source=lambda: read_plugin_runtime(web_cache))
-        catalog.discover_plugins()
-        return catalog
-
-    def test_live_display_modes_win_over_the_manifest(self, plugins_dir, shared_cache):
-        display_cache, web_cache = shared_cache
-        PluginRuntimePublisher(display_cache, _loaded_states(REGISTERED)).tick()
-        catalog = self._catalog(plugins_dir, web_cache)
-        assert catalog.get_plugin_display_modes("soccer-scoreboard") == REGISTERED
-
-    def test_a_custom_league_mode_resolves_to_its_plugin(self, plugins_dir, shared_cache):
-        """What /display/on-demand/start does with a mode and no plugin_id."""
-        display_cache, web_cache = shared_cache
-        PluginRuntimePublisher(display_cache, _loaded_states(REGISTERED)).tick()
-        catalog = self._catalog(plugins_dir, web_cache)
-        assert catalog.find_plugin_for_mode("SOCCER_SCO.1_LIVE") == "soccer-scoreboard"
-
-    def test_a_plugin_the_display_has_not_loaded_falls_back_to_its_manifest(
-            self, plugins_dir, shared_cache):
-        display_cache, web_cache = shared_cache
-        PluginRuntimePublisher(display_cache, _loaded_states(REGISTERED)).tick()
-        catalog = self._catalog(plugins_dir, web_cache)
-        assert catalog.get_plugin_display_modes("clock-simple") == ["clock"]
-        assert catalog.find_plugin_for_mode("clock") == "clock-simple"
-
-    def test_a_mode_the_display_dropped_does_not_resolve_by_manifest(
-            self, plugins_dir, shared_cache):
-        display_cache, web_cache = shared_cache
-        PluginRuntimePublisher(display_cache, _loaded_states(CUSTOM)).tick()
-        catalog = self._catalog(plugins_dir, web_cache)
-        assert catalog.find_plugin_for_mode("soccer_eng.1_live") is None
-
-    def test_a_stopped_display_falls_back_to_manifests(self, plugins_dir, shared_cache):
-        display_cache, web_cache = shared_cache
-        publisher = PluginRuntimePublisher(display_cache, _loaded_states(REGISTERED))
-        publisher.tick()
-        publisher.stop()
-        catalog = self._catalog(plugins_dir, web_cache)
-        assert catalog.get_plugin_display_modes("soccer-scoreboard") == DECLARED
-        assert catalog.find_plugin_for_mode("soccer_sco.1_live") is None
-
-    def test_no_runtime_source_is_manifests_only(self, plugins_dir):
-        catalog = PluginCatalog(plugins_dir)
-        catalog.discover_plugins()
-        assert catalog.get_plugin_display_modes("soccer-scoreboard") == DECLARED
-
-    def test_a_failing_runtime_source_is_manifests_only(self, plugins_dir):
-        def broken():
-            raise OSError("cache gone")
-        catalog = PluginCatalog(plugins_dir, runtime_source=broken)
-        catalog.discover_plugins()
-        assert catalog.get_plugin_display_modes("soccer-scoreboard") == DECLARED
-
-    def test_one_listing_reads_the_view_once(self, plugins_dir):
-        source = MagicMock(return_value=None)
-        catalog = PluginCatalog(plugins_dir, runtime_source=source)
-        catalog.discover_plugins()
-        for _ in range(10):
-            catalog.get_plugin_display_modes("soccer-scoreboard")
-            catalog.find_plugin_for_mode("clock")
-        assert source.call_count == 1
-
-
-class TestDisplayModesRoute:
-    def test_lists_the_custom_league_modes(self, api_v3_module, api_v3_client,  # noqa: F811
-                                           plugins_dir, shared_cache):
-        display_cache, web_cache = shared_cache
-        PluginRuntimePublisher(display_cache, _loaded_states(REGISTERED)).tick()
-        api = api_v3_module.api_v3
-        api.plugin_catalog = PluginCatalog(
-            plugins_dir, runtime_source=lambda: read_plugin_runtime(web_cache))
-        api.config_manager.load_config = MagicMock(return_value={
-            "soccer-scoreboard": {"enabled": True}})
-
-        response = api_v3_client.get("/api/v3/display/modes")
-
-        assert response.status_code == 200, response.get_data(as_text=True)
-        modes = {m["mode"]: m for m in response.get_json()["data"]["modes"]}
-        assert set(modes) == set(REGISTERED)
-        assert modes["soccer_sco.1_live"]["plugin_id"] == "soccer-scoreboard"

test/test_plugin_runtime_snapshot.py

@@ -162,7 +162,7 @@ class TestPublisher:
         assert snapshot["stale_after"] == rt.STALE_AFTER
         assert snapshot["plugins"] == {"clock": {
             "loaded": True, "state": "enabled", "error": None,
-            "version": "1.0.0", "loaded_at": 10.0, "modes": None}}
+            "version": "1.0.0", "loaded_at": 10.0}}
 
     def test_changes_are_throttled_and_quiet_displays_refresh(self):
         cache = MagicMock()

test/test_sports_helpers.py

@@ -8,9 +8,7 @@ loses those tests with it.
 The parity class is what keeps "byte-identical" true after this lands. Point
 LEDMATRIX_PLUGINS at a ledmatrix-plugins checkout and every promoted body is
 compared, as a docstring-stripped AST, against every plugin copy that carries
-it. A copy that is gone counts as adopted when the plugin imports
-src.common.sports_helpers (plugins#563/#564 did that for every scoreboard).
-Without the variable it skips rather than fails, since core CI has no
+it. Without the variable it skips rather than fails, since core CI has no
 plugins checkout; ledmatrix-plugins CI runs the same comparison against core
 (scripts/check_sports_helpers_parity.py, ledmatrix-plugins#495).
 """
@@ -574,24 +572,6 @@ def _core_definitions():
     return out
 
 
-def _sports_source(root, sport):
-    return (root / f"{sport}-scoreboard" / "sports.py").read_text(encoding="utf-8")
-
-
-def _adopted(source):
-    """Gone is fine once the plugin uses the module; otherwise the finder is
-    not seeing its copy."""
-    name = sports_helpers.__name__
-    for node in ast.walk(ast.parse(source)):
-        if isinstance(node, ast.ImportFrom):
-            if node.module == name or any(
-                    f"{node.module}.{a.name}" == name for a in node.names):
-                return True
-        elif isinstance(node, ast.Import) and any(a.name == name for a in node.names):
-            return True
-    return False
-
-
 class TestParityWithPlugins:
     @pytest.mark.parametrize("name", sorted(PROMOTED))
     def test_body_matches_every_plugin_copy(self, name):
@@ -600,10 +580,10 @@ class TestParityWithPlugins:
         ours = _dump(_core_definitions()[name])
         drifted, missing = [], []
         for sport in carriers:
-            source = _sports_source(root, sport)
-            theirs = _definitions(ast.parse(source))[where].get(plugin_name)
+            defs = _definitions(ast.parse(
+                (root / f"{sport}-scoreboard" / "sports.py").read_text(encoding="utf-8")))
+            theirs = defs[where].get(plugin_name)
             if theirs is None:
-                if not _adopted(source):
                 missing.append(sport)
             elif _dump(theirs) != ours:
                 drifted.append(sport)
@@ -614,20 +594,10 @@ class TestParityWithPlugins:
 
     @pytest.mark.parametrize("sport", SCOREBOARDS)
     def test_constants_match(self, sport):
-        source = _sports_source(_plugins_root(), sport)
-        defs = _definitions(ast.parse(source))
-        expected = {
-            ("module", "_MIN_WINDOW_DAYS"): MIN_WINDOW_DAYS,
-            ("module", "_MAX_WINDOW_DAYS"): MAX_WINDOW_DAYS,
-            ("SportsCore", "_DWELL_REENTRY_GAP_SECONDS"):
-                SportsHelpersMixin._DWELL_REENTRY_GAP_SECONDS,
-        }
-        missing = []
-        for (where, name), value in expected.items():
-            node = defs[where].get(name)
-            if node is None:
-                if not _adopted(source):
-                    missing.append(name)
-            else:
-                assert math.isclose(ast.literal_eval(node.value), value), name
-        assert missing == [], f"not found in {sport}: {missing}"
+        root = _plugins_root()
+        defs = _definitions(ast.parse(
+            (root / f"{sport}-scoreboard" / "sports.py").read_text(encoding="utf-8")))
+        assert ast.literal_eval(defs["module"]["_MIN_WINDOW_DAYS"].value) == MIN_WINDOW_DAYS
+        assert ast.literal_eval(defs["module"]["_MAX_WINDOW_DAYS"].value) == MAX_WINDOW_DAYS
+        gap = defs["SportsCore"]["_DWELL_REENTRY_GAP_SECONDS"].value
+        assert math.isclose(ast.literal_eval(gap), SportsHelpersMixin._DWELL_REENTRY_GAP_SECONDS)

test/test_web_error_detail.py

@@ -11,26 +11,32 @@ than even logging it.
 
 import pytest
 
-from src.web_interface.error_handler import describe_exception
+from src.web_interface.error_handler import describe_exception, redact_text
 
 
 class TestDescribeException:
-    def test_names_the_type_and_message(self):
-        detail = describe_exception(OSError(5, "Input/output error", "systemctl"))
-        assert detail == "OSError: [Errno 5] Input/output error: 'systemctl'"
+    """describe_exception is a reason code: type and errno, never the message.
 
-    def test_the_reported_failure_is_legible(self):
-        # The whole point: this string is the diagnosis.
-        assert "Input/output error" in describe_exception(
-            OSError(5, "Input/output error", "systemctl"))
+    The message can quote paths, URLs or credentials (CodeQL
+    py/stack-trace-exposure), so it goes to the log; the code still names the
+    fault, as "[Errno 5]" did.
+    """
+
+    def test_an_oserror_names_its_errno(self):
+        assert describe_exception(
+            OSError(5, "Input/output error", "systemctl")) == "OSError:EIO"
 
     def test_a_bare_exception_still_names_its_type(self):
-        # A PermissionError with no message still says more than "unknown".
         assert describe_exception(PermissionError()) == "PermissionError"
         assert describe_exception(Exception()) == "Exception"
 
-    def test_message_is_kept_when_present(self):
-        assert describe_exception(ValueError("bad port")) == "ValueError: bad port"
+    def test_the_message_never_reaches_the_code(self):
+        assert describe_exception(ValueError("bad port /etc/secret")) == "ValueError"
+
+    def test_the_message_is_logged_instead(self, caplog):
+        describe_exception(RuntimeError("disk on fire token=abc123"))
+        assert "disk on fire" in caplog.text
+        assert "abc123" not in caplog.text
 
 
 class TestCredentialRedaction:
@@ -56,47 +62,44 @@ class TestCredentialRedaction:
         ("authorization: barecredential", "barecredential"),
     ])
     def test_credentials_never_reach_the_response(self, secret_text, leaked):
-        detail = describe_exception(RuntimeError(secret_text))
+        detail = redact_text(secret_text)
         assert leaked not in detail
         assert "<redacted>" in detail
 
     def test_the_parameter_name_survives_redaction(self):
         # Knowing *which* credential was involved is part of the diagnosis.
-        detail = describe_exception(RuntimeError("https://x/y?api_key=SEC123"))
+        detail = redact_text("https://x/y?api_key=SEC123")
         assert "api_key" in detail
 
     def test_unknown_schemes_keep_their_name(self):
         for scheme in ("ApiKey", "Negotiate", "NTLM", "AWS4-HMAC-SHA256"):
-            detail = describe_exception(
-                RuntimeError("Authorization: %s SECRETVALUE" % scheme))
+            detail = redact_text("Authorization: %s SECRETVALUE" % scheme)
             assert scheme in detail, detail
             assert "SECRETVALUE" not in detail, detail
 
     def test_auth_scheme_and_username_survive(self):
         # Which kind of credential, and whose, without the credential itself.
-        assert "Bearer" in describe_exception(
-            RuntimeError("Authorization: Bearer eyJ.SECRET.sig"))
-        assert "user" in describe_exception(
-            RuntimeError("https://user:hunter2@example.com"))
+        assert "Bearer" in redact_text("Authorization: Bearer eyJ.SECRET.sig")
+        assert "user" in redact_text("https://user:hunter2@example.com")
 
     def test_non_secret_context_is_preserved(self):
-        detail = describe_exception(RuntimeError("https://api.x.com/v1?city=Tampa"))
+        detail = redact_text("https://api.x.com/v1?city=Tampa")
         assert "city=Tampa" in detail
         assert "<redacted>" not in detail
 
 
 class TestBounds:
     def test_long_messages_are_truncated(self):
-        detail = describe_exception(ValueError("x" * 5000))
+        detail = redact_text("x" * 5000)
         assert len(detail) <= 400
 
     def test_newlines_are_collapsed_to_one_line(self):
-        detail = describe_exception(ValueError("line one\nline two\tthree"))
+        detail = redact_text("line one\nline two\tthree")
         assert "\n" not in detail and "\t" not in detail
-        assert detail == "ValueError: line one line two three"
+        assert detail == "line one line two three"
 
     def test_custom_length_is_honoured(self):
-        assert len(describe_exception(ValueError("y" * 500), max_length=50)) <= 50
+        assert len(redact_text("y" * 500, max_length=50)) <= 50
 
 
 class TestHandlersCarryDetail:
@@ -319,10 +322,10 @@ class TestHandlersCarryDetail:
         assert resp.status_code == 405, "a wrong method must stay a 405"
         assert resp.get_json()["error_code"] == "METHOD_NOT_ALLOWED"
 
-        # A genuine server fault still reports as one, with its detail.
+        # A genuine server fault still reports as one, with its reason code.
         resp = client.get("/boom")
         assert resp.status_code == 500
-        assert "Input/output error" in resp.get_json()["details"]
+        assert resp.get_json()["details"] == "OSError:EIO"
 
     def test_global_handler_reports_the_underlying_error(self):
         from flask import Flask, jsonify
@@ -345,4 +348,5 @@ class TestHandlersCarryDetail:
         client = app.test_client()
         body = client.get("/boom").get_json()
         assert body["error_code"] == "UNKNOWN_ERROR"
-        assert "Input/output error" in body["details"]
+        assert body["details"] == "OSError:EIO"
+        assert "Input/output error" not in str(body)

test/web_interface/test_api_v3_unhandled_errors.py

@@ -114,12 +114,11 @@ def test_the_answer_is_what_the_catch_all_returned(client, caplog, method, url,
     assert records[-1].exc_info[1] is FORCED
 
 
-def test_credentials_are_redacted_from_the_detail(client):
+def test_the_exception_message_never_reaches_the_detail(client):
     body = client.get("/api/v3/plugins/installed").get_json()
-    for secret in ("SECRET123", "pw1", "K1"):
-        assert secret not in body["details"]
-    assert "<redacted>" in body["details"]
-    assert body["details"].startswith("RuntimeError: forced failure")
+    for secret in ("SECRET123", "pw1", "K1", "forced failure"):
+        assert secret not in str(body)
+    assert body["details"] == "RuntimeError"
 
 
 def _raise_415():
@@ -218,7 +217,7 @@ class TestPluginActionStep1:
             encoding="utf-8")
         return d
 
-    def test_the_script_error_reaches_the_response(self, plugin_dir, monkeypatch):
+    def test_the_script_error_is_reported_by_type(self, plugin_dir, monkeypatch):
         from unittest.mock import MagicMock
         manager = MagicMock()
         manager.get_plugin_directory.return_value = str(plugin_dir)
@@ -232,5 +231,6 @@ class TestPluginActionStep1:
 
         assert resp.status_code == 500
         body = resp.get_json()
-        assert body["details"] == "RuntimeError: the auth script failed"
+        assert body["details"] == "RuntimeError"
+        assert "the auth script failed" not in str(body)
         assert body["message"] == 'An error occurred; see logs for details'

test/web_interface/test_starlark_pixlet_routes.py

@@ -946,21 +946,27 @@ class TestTheStoreReportsWhyItIsEmpty:
 
 
 class TestACrashCarriesItsDetail:
-    """Seventeen Starlark handlers answered 5xx with no detail at all."""
+    """Seventeen Starlark handlers answered 5xx with no detail at all.
 
-    def test_browse_returns_the_exception_detail(self, client):
+    The detail is a reason code (the exception type), not the exception's
+    message, which stays in the log (CodeQL py/stack-trace-exposure).
+    """
+
+    def test_browse_returns_the_reason_code(self, client):
         with patch('web_interface.blueprints.api_v3._get_tronbyte_repository_class',
                    side_effect=ImportError("No module named 'yaml'")):
             body = client.get('/api/v3/starlark/repository/browse').get_json()
 
-        assert 'yaml' in body.get('details', ''), body
+        assert body.get('details') == 'ImportError', body
+        assert 'yaml' not in str(body), body
 
-    def test_status_returns_the_exception_detail(self, client):
+    def test_status_returns_the_reason_code(self, client):
         with patch('web_interface.blueprints.api_v3._get_starlark_plugin',
                    side_effect=RuntimeError("plugin manager is not attached")):
             body = client.get('/api/v3/starlark/status').get_json()
 
-        assert 'plugin manager is not attached' in body.get('details', ''), body
+        assert body.get('details') == 'RuntimeError', body
+        assert 'plugin manager is not attached' not in str(body), body
 
 
 class TestTheListingIsNotCappedAtOneThousand:

web_interface/app.py

@@ -159,18 +159,10 @@ schema_manager = SchemaManager(
 # saves reach the running plugins through the display's config watcher; what
 # the display knows at run time (health, metrics, errors, current mode) it
 # publishes to the shared cache. See docs/ARCHITECTURE.md.
-def _catalog_runtime_view():
-    """The display's runtime view, for the catalog's mode lookups. Imported
-    on call, as the startup reconciliation below imports it."""
-    from web_interface.blueprints.api_v3 import _plugin_runtime_view
-    return _plugin_runtime_view()
-
-
 plugin_catalog = PluginCatalog(
     plugins_dir=plugins_dir,
     config_manager=config_manager,
     schema_manager=schema_manager,
-    runtime_source=_catalog_runtime_view,
 )
 
 # Initialize operation queue for plugin operations

web_interface/blueprints/api_v3/__init__.py

@@ -222,7 +222,7 @@ def _save_config_atomic(config_manager, config_data, create_backup=True):
             config_manager.save_config(config_data)
             return True, None
         except Exception as e:
-            return False, str(e)
+            return False, f"Failed to save configuration ({describe_exception(e)})"
 def _coerce_to_bool(value):
     """
     Coerce a form value to a proper Python boolean.
@@ -246,7 +246,11 @@ def _coerce_to_bool(value):
         return value.lower() in ('true', 'on', '1', 'yes')
     return False
 def _get_display_service_status():
-    """Return status information about the ledmatrix service."""
+    """Return status information about the ledmatrix service.
+
+    active/returncode only: this goes back in API responses, and systemctl's
+    output (or an exception's text) is logged rather than returned.
+    """
     try:
         result = subprocess.run(
             ['systemctl', 'is-active', 'ledmatrix'],
@@ -254,26 +258,18 @@ def _get_display_service_status():
             text=True,
             timeout=3
         )
+        if result.stderr.strip():
+            logger.debug('systemctl is-active ledmatrix: %s', result.stderr.strip())
         return {
             'active': result.stdout.strip() == 'active',
             'returncode': result.returncode,
-            'stdout': result.stdout.strip(),
-            'stderr': result.stderr.strip()
         }
     except subprocess.TimeoutExpired:
-        return {
-            'active': False,
-            'returncode': -1,
-            'stdout': '',
-            'stderr': 'timeout'
-        }
-    except Exception as err:
-        return {
-            'active': False,
-            'returncode': -1,
-            'stdout': '',
-            'stderr': str(err)
-        }
+        logger.warning('systemctl is-active ledmatrix timed out')
+        return {'active': False, 'returncode': -1}
+    except Exception:
+        logger.warning('Could not query ledmatrix.service status', exc_info=True)
+        return {'active': False, 'returncode': -1}
 def _run_systemctl_command(args):
     """Run a systemctl command safely."""
     try:
@@ -295,18 +291,26 @@ def _run_systemctl_command(args):
             'stderr': 'timeout'
         }
     except Exception as err:
+        logger.warning('%s failed', ' '.join(args), exc_info=True)
         return {
             'returncode': -1,
             'stdout': '',
-            'stderr': str(err)
+            'stderr': describe_exception(err)
         }
+def _public_service_result(result):
+    """A _run_systemctl_command result fit for a response: no stdout/stderr."""
+    if result.get('returncode') != 0:
+        logger.error('systemctl exited %s: %s', result.get('returncode'),
+                     (result.get('stderr') or '').strip())
+    return {k: v for k, v in result.items() if k not in ('stdout', 'stderr')}
 def _ensure_display_service_running():
     """Ensure the ledmatrix display service is running."""
     status = _get_display_service_status()
     if status.get('active'):
         status['started'] = False
         return status
-    result = _run_systemctl_command(['sudo', 'systemctl', 'start', 'ledmatrix.service'])
+    result = _public_service_result(
+        _run_systemctl_command(['sudo', 'systemctl', 'start', 'ledmatrix.service']))
     service_status = _get_display_service_status()
     result['started'] = result.get('returncode') == 0
     result['active'] = service_status.get('active')
@@ -314,7 +318,8 @@ def _ensure_display_service_running():
     return result
 def _stop_display_service():
     """Stop the ledmatrix display service."""
-    result = _run_systemctl_command(['sudo', 'systemctl', 'stop', 'ledmatrix.service'])
+    result = _public_service_result(
+        _run_systemctl_command(['sudo', 'systemctl', 'stop', 'ledmatrix.service']))
     status = _get_display_service_status()
     result['active'] = status.get('active')
     result['status'] = status
@@ -712,7 +717,7 @@ def _do_transactional_uninstall(plugin_id, preserve_config):
         success = api_v3.plugin_store_manager.uninstall_plugin(plugin_id)
     except Exception as remove_err:
         _rollback()
-        return False, f"Failed to remove plugin {plugin_id}: {remove_err}"
+        return False, f"Failed to remove plugin {plugin_id} ({describe_exception(remove_err)})"
 
     if not success:
         _rollback()

web_interface/blueprints/api_v3/display.py

@@ -153,12 +153,10 @@ def get_display_modes():
     same list the force-display dialog offers, from the source that owns it.
 
     Knowing each mode's plugin_id also matters because /display/on-demand/start
-    falls back to find_plugin_for_mode when plugin_id is omitted. While the
-    display is running, both that lookup and this list use the modes it
-    registered, so modes a plugin generates from its config (each installed
-    Starlark app, each soccer custom league) are found (#668); with the
-    display stopped they see only what manifests declare. Sending the
-    plugin_id from this list skips the lookup entirely.
+    falls back to find_plugin_for_mode when plugin_id is omitted, and that
+    lookup only sees modes declared in a static manifest -- a plugin whose
+    modes are generated (each installed Starlark app is one) 404s there.
+    Sending the plugin_id from this list skips the lookup entirely.
 
     Query params:
         include_disabled: '1' to list modes of disabled plugins too. They can
@@ -279,15 +277,6 @@ def start_on_demand_display():
             if not resolved_plugin:
                 return jsonify({'status': 'error', 'message': f'Mode {resolved_mode} not found'}), 404
 
-    # The display matches mode names exactly: pass the registered spelling
-    # when the caller's differs only in case.
-    if api_v3.plugin_catalog and resolved_plugin and resolved_mode:
-        wanted = resolved_mode.strip().lower()
-        for registered in api_v3.plugin_catalog.get_plugin_display_modes(resolved_plugin):
-            if isinstance(registered, str) and registered.lower() == wanted:
-                resolved_mode = registered
-                break
-
     # On-demand works with disabled plugins: the running display loads one
     # for the session and unloads it afterwards, leaving config.json alone
     # (DisplayController._load_plugin_for_on_demand). Logged for debugging.

web_interface/blueprints/api_v3/plugins.py

@@ -150,9 +150,8 @@ def get_installed_plugins():
         vegas_participation, vegas_participation_source = _vegas_participation(
             plugin_id, plugin_config, plugin_info)
 
-        # The plugin's modes, from the catalog as /display/modes and
-        # on-demand/start read them: what the running display registered,
-        # else what the manifest declares. The on-demand modal offers these;
+        # The modes the manifest declares, from the catalog as /display/modes
+        # and on-demand/start read them. The on-demand modal offers these;
         # without them it offered only the plugin id, which the display
         # turns into the first mode. Strings only: a manifest is hand-edited.
         declared_modes = api_v3.plugin_catalog.get_plugin_display_modes(plugin_id)

web_interface/blueprints/api_v3/starlark.py

@@ -983,7 +983,6 @@ def stop_pixlet_editor():
                     'status': 'error',
                     'message': 'Editor force-stopped, but the display could not be '
                                'restarted automatically - start it manually.',
-                    'details': (result.get('stderr') or '').strip(),
                     'data': {'running': False}}), 500
             return jsonify({'status': 'success',
                             'message': 'Editor force-stopped; the display has been '

web_interface/blueprints/api_v3/system.py

@@ -689,7 +689,7 @@ def execute_system_action():
                     logger.warning("install_base_requirements timed out for %s", label)
                 except OSError as install_err:
                     all_ok = False
-                    outputs.append(f"== {label} ==\nFailed: {install_err}")
+                    outputs.append(f"== {label} ==\nFailed: {describe_exception(install_err)}")
                     logger.warning("install_base_requirements errored for %s: %s", label, install_err)
             return jsonify({
                 'status': 'success' if all_ok else 'error',
@@ -784,11 +784,10 @@ def execute_system_action():
         return jsonify({'status': 'error', 'message': 'Command timed out', 'returncode': -1, 'stderr': 'timeout'})
     except Exception as e:
         logger.error("execute_system_action failed: %s", e, exc_info=True)
-        detail = describe_exception(e)
         resp = {
             'status': 'error',
-            'message': _sudo_hint_for(detail) or 'Action failed; see logs for details',
-            'details': detail,
+            'message': _sudo_hint_for(str(e)) or 'Action failed; see logs for details',
+            'details': describe_exception(e),
         }
         return jsonify(resp), 500
 @api_v3.route('/system/git-info', methods=['GET'])

web_interface/blueprints/api_v3/wifi.py

@@ -67,7 +67,7 @@ def _run_background_connect(ssid, password):
         payload = _connect_result_payload(ssid, success, message)
     except Exception as e:
         logger.error("Background WiFi connect failed", exc_info=True)
-        payload = {'status': 'error', 'message': describe_exception(e)}
+        payload = {'status': 'error', 'message': f'Failed to connect to network ({describe_exception(e)})'}
     _record_connect_result(ssid, payload)
 
 
@@ -276,7 +276,7 @@ def connect_wifi():
     try:
         success, message = wifi_manager.connect_to_network(ssid, password)
     except Exception as e:
-        _record_connect_result(ssid, {'status': 'error', 'message': describe_exception(e)})
+        _record_connect_result(ssid, {'status': 'error', 'message': f'Failed to connect to network ({describe_exception(e)})'})
         raise
     payload = _connect_result_payload(ssid, success, message)
     _record_connect_result(ssid, payload)

web_interface/unit_refresh.py

@@ -86,7 +86,7 @@ def refresh_after_update(run=None, systemd_dir=None, helper_source=None, helper_
     except Exception as e:  # a broken template must not fail the update itself
         if type(e).__name__ != 'UnitsUnreadable':
             logger.warning("Could not compare the installed systemd units with the new templates: %s", e)
-            return _result(FAILED, f'The service settings could not be checked: {e}.')
+            return _result(FAILED, 'The service settings could not be checked; see logs for details.')
         # Units installed mode 0600 (install_service.sh run on its own, before
         # it set 0644): only root can compare them, so let the helper decide.
         stale = []
@@ -110,7 +110,7 @@ def refresh_after_update(run=None, systemd_dir=None, helper_source=None, helper_
                      timeout=TIMEOUT_SECONDS)
     except (subprocess.SubprocessError, OSError) as e:
         logger.warning("Refreshing the systemd units failed: %s", e)
-        return _result(FAILED, f'Updating the service settings ({names}) failed: {e}.', stale)
+        return _result(FAILED, f'Updating the service settings ({names}) failed; see logs for details.', stale)
     if result.returncode == 0:
         # The helper says what it did: "units refreshed: a b" or "units: up to date".
         done = next((line.split(':', 1)[1].split() for line in (result.stdout or '').splitlines()