fix(tools): harden scheduler and diagnostics

- preserve same-queue scheduler starts across superseded Run Now generations while retaining Stop cancellation
- pause saved and tracked scheduler ownership, fence engine cache writes, and normalize log merge/redaction boundaries
- add postcondition regressions for scheduler handoff, engine request generations, compact JSON redaction, and live log overlap

src-tauri/src/lib.rs

@@ -11364,7 +11364,7 @@ pub(crate) fn redact_sensitive_text(line: &str) -> String {
             .expect("valid sensitive header redaction regex")
     });
     let query = QUERY.get_or_init(|| {
-        regex::Regex::new(r"([A-Za-z][A-Za-z0-9+.-]*://[^\s?]+)\?[^\s]+")
+        regex::Regex::new(r#"([A-Za-z][A-Za-z0-9+.-]*://[^\s?\"'<>},\]]+)\?[^\s\"'<>},\]]+"#)
             .expect("valid URL query redaction regex")
     });
     let userinfo = USERINFO.get_or_init(|| {
@@ -11375,13 +11375,13 @@ pub(crate) fn redact_sensitive_text(line: &str) -> String {
         regex::Regex::new(r"([A-Za-z][A-Za-z0-9+.-]*://[^\s?#]+)#\S+")
             .expect("valid URL fragment redaction regex")
     });
-    let redacted = header.replace_all(line, "$1: [redacted]");
-    let redacted = quoted_secret.replace_all(&redacted, "$1$2$3$4[redacted]");
-    let redacted = secret.replace_all(&redacted, "$1=[redacted]");
+    let redacted = query.replace_all(line, "$1?[redacted]");
+    let redacted = fragment.replace_all(&redacted, "$1#[redacted]");
     let redacted = userinfo.replace_all(&redacted, "$1[redacted]@");
-    let redacted = query.replace_all(&redacted, "$1?[redacted]");
-    fragment
-        .replace_all(&redacted, "$1#[redacted]")
+    let redacted = header.replace_all(&redacted, "$1: [redacted]");
+    let redacted = quoted_secret.replace_all(&redacted, "$1$2$3$4[redacted]");
+    secret
+        .replace_all(&redacted, "$1=[redacted]")
         .into_owned()
 }
 
@@ -14122,6 +14122,17 @@ mod tests {
         assert!(redacted.contains("[redacted]"));
     }
 
+    #[test]
+    fn preserves_compact_json_delimiters_while_redacting_url_queries() {
+        let redacted = redact_log_line(
+            r#"{"url":"https://example.com/file?token=secret","next":1}"#,
+        );
+        assert_eq!(
+            redacted,
+            r#"{"url":"https://example.com/file?[redacted]","next":1}"#
+        );
+    }
+
     #[test]
     fn collects_primary_url_and_unique_mirrors_in_order() {
         let uris = collect_download_uris(

src/App.tsx

@@ -43,7 +43,12 @@ import { synchronizeDocumentAppearance } from './utils/documentAppearance';
 import { createMainWindowSizePersistence } from './utils/mainWindowState';
 import { createSidebarResizeSession } from './utils/sidebarResize';
 import type { MainWindowSize } from './bindings/MainWindowSize';
-import { beginSchedulerControl, isSchedulerControlCurrent } from './utils/schedulerControl';
+import {
+  beginSchedulerControl,
+  consumeSchedulerHandoffIds,
+  handoffSupersededSchedulerIds,
+  isSchedulerControlCurrent
+} from './utils/schedulerControl';
 import { createSerialTaskQueue } from './utils/serialTaskQueue';
 
 const loadSettingsView = () => import('./components/SettingsView');
@@ -921,9 +926,9 @@ function App() {
       processingScheduleKeys.add(payload.key);
       try {
         if (payload.action === 'start') {
-          const generation = beginSchedulerControl();
           clearPendingPostActionTimer();
           const scheduledQueueIds = getScheduledQueueIds();
+          const generation = beginSchedulerControl(scheduledQueueIds);
           if (scheduledQueueIds.length === 0) {
             state.setSchedulerActiveDownloadIds([]);
             state.setSchedulerRunning(false);
@@ -941,16 +946,23 @@ function App() {
           );
           const acceptedIds = startedResults.flat();
           if (!isSchedulerControlCurrent(generation)) {
+            const handoffIds = handoffSupersededSchedulerIds(
+              acceptedIds,
+              id => useDownloadStore.getState().downloads.find(download => download.id === id)?.queueId || MAIN_QUEUE_ID
+            );
             await Promise.allSettled(
-              acceptedIds.map(id => useDownloadStore.getState().pauseDownload(id))
+              acceptedIds
+                .filter(id => !handoffIds.has(id))
+                .map(id => useDownloadStore.getState().pauseDownload(id))
             );
             await invoke('ack_schedule_trigger', { action: 'start', key: payload.key });
             return;
           }
           const scheduledQueueSet = new Set(scheduledQueueIds);
+          const handoffIds = consumeSchedulerHandoffIds(generation);
           const trackedIds = useDownloadStore.getState().downloads
             .filter(download =>
-              previouslyTrackedIds.has(download.id) &&
+              (previouslyTrackedIds.has(download.id) || handoffIds.has(download.id)) &&
               scheduledQueueSet.has(download.queueId || MAIN_QUEUE_ID) &&
               isActiveDownloadStatus(download.status)
             )

src/components/SchedulerView.tsx

@@ -12,7 +12,12 @@ import { useToast } from '../contexts/ToastContext';
 import { usePlatformInfo } from '../utils/platform';
 import { useTranslation } from 'react-i18next';
 import { formatDateTime } from '../utils/dateTime';
-import { beginSchedulerControl, isSchedulerControlCurrent } from '../utils/schedulerControl';
+import {
+  beginSchedulerControl,
+  consumeSchedulerHandoffIds,
+  handoffSupersededSchedulerIds,
+  isSchedulerControlCurrent
+} from '../utils/schedulerControl';
 
 const days = [
   { value: 0, key: 'su' },
@@ -162,22 +167,29 @@ export default function SchedulerView() {
   };
 
   const runNow = async () => {
-    const generation = beginSchedulerControl();
+    const generation = beginSchedulerControl(effectiveSelectedQueueIds);
     const previouslyTrackedIds = new Set(useSettingsStore.getState().schedulerActiveDownloadIds);
     const results = await Promise.all(
       effectiveSelectedQueueIds.map(queueId => useDownloadStore.getState().startQueue(queueId))
     );
     const acceptedIds = results.flat();
     if (!isSchedulerControlCurrent(generation)) {
+      const handoffIds = handoffSupersededSchedulerIds(
+        acceptedIds,
+        id => useDownloadStore.getState().downloads.find(download => download.id === id)?.queueId || MAIN_QUEUE_ID
+      );
       await Promise.allSettled(
-        acceptedIds.map(id => useDownloadStore.getState().pauseDownload(id))
+        acceptedIds
+          .filter(id => !handoffIds.has(id))
+          .map(id => useDownloadStore.getState().pauseDownload(id))
       );
       return;
     }
     const selectedQueueSet = new Set(effectiveSelectedQueueIds);
+    const handoffIds = consumeSchedulerHandoffIds(generation);
     const trackedIds = useDownloadStore.getState().downloads
       .filter(download =>
-        previouslyTrackedIds.has(download.id) &&
+        (previouslyTrackedIds.has(download.id) || handoffIds.has(download.id)) &&
         selectedQueueSet.has(download.queueId || MAIN_QUEUE_ID) &&
         isActiveDownloadStatus(download.status)
       )
@@ -199,11 +211,23 @@ export default function SchedulerView() {
 
   const pauseNow = async () => {
     const generation = beginSchedulerControl();
+    const savedQueueIds = savedSettings.selectedQueueIds
+      .filter(queueId => availableQueueIds.has(queueId));
+    const savedQueueSet = new Set(savedQueueIds);
+    const trackedIdsOutsideSavedQueues = useSettingsStore.getState().schedulerActiveDownloadIds
+      .filter(id => {
+        const queueId = useDownloadStore.getState().downloads.find(download => download.id === id)?.queueId || MAIN_QUEUE_ID;
+        return !savedQueueSet.has(queueId);
+      });
     const counts = await Promise.all(
-      effectiveSelectedQueueIds.map(queueId => useDownloadStore.getState().pauseQueue(queueId))
+      savedQueueIds.map(queueId => useDownloadStore.getState().pauseQueue(queueId))
+    );
+    const directPauseResults = await Promise.allSettled(
+      trackedIdsOutsideSavedQueues.map(id => useDownloadStore.getState().pauseDownload(id))
     );
     if (!isSchedulerControlCurrent(generation)) return;
-    const count = counts.reduce((total, queueCount) => total + queueCount, 0);
+    const count = counts.reduce((total, queueCount) => total + queueCount, 0)
+      + directPauseResults.filter(result => result.status === 'fulfilled').length;
     useSettingsStore.getState().setSchedulerRunning(false);
     useSettingsStore.getState().setSchedulerActiveDownloadIds([]);
     addToast({

src/components/SettingsView.tsx

@@ -51,6 +51,7 @@ import {
 } from '../utils/downloads';
 import { useTranslation } from 'react-i18next';
 import { localeDirection, resolveAppLocale } from '../i18n';
+import { createEngineStatusRequestTracker } from '../utils/engineStatusRequests';
 
 const settingsTabs: { type: SettingsTab; icon: typeof Download }[] = [
   { type: 'downloads', icon: Download },
@@ -222,6 +223,7 @@ const networkSettingsSectionFromStorage = (): NetworkSettingsSection => {
 
 const engineStatusCache = new Map<string, EngineStatusItem>();
 const engineStatusInFlight = new Map<string, Promise<EngineStatusItem>>();
+const engineStatusRequests = createEngineStatusRequestTracker();
 
 const upsertEngineStatus = (items: EngineStatusItem[], item: EngineStatusItem) => {
   const next = items.filter(existing => existing.kind !== item.kind);
@@ -309,10 +311,13 @@ const runEngineStatusCheck = (check: EngineCheck, force: boolean) => {
   }
 
   if (force) engineStatusCache.delete(check.kind);
+  const requestId = engineStatusRequests.begin(check.kind);
 
   const promise = invoke(check.command)
     .then(item => {
-      if (item.ready) engineStatusCache.set(item.kind, item);
+      if (item.ready && engineStatusRequests.isCurrent(check.kind, requestId)) {
+        engineStatusCache.set(item.kind, item);
+      }
       return item;
     })
     .catch(error => buildEngineStatusError(check, error))

src/utils/engineStatusRequests.test.ts

@@ -0,0 +1,22 @@
+import { describe, expect, it } from 'vitest';
+import { createEngineStatusRequestTracker } from './engineStatusRequests';
+
+describe('engine status request tracker', () => {
+  it('invalidates an older result for the same engine after a forced recheck', () => {
+    const tracker = createEngineStatusRequestTracker();
+    const first = tracker.begin('aria2');
+    const second = tracker.begin('aria2');
+
+    expect(tracker.isCurrent('aria2', first)).toBe(false);
+    expect(tracker.isCurrent('aria2', second)).toBe(true);
+  });
+
+  it('keeps independent engine checks current independently', () => {
+    const tracker = createEngineStatusRequestTracker();
+    const aria2 = tracker.begin('aria2');
+    const ytdlp = tracker.begin('ytdlp');
+
+    expect(tracker.isCurrent('aria2', aria2)).toBe(true);
+    expect(tracker.isCurrent('ytdlp', ytdlp)).toBe(true);
+  });
+});

src/utils/engineStatusRequests.ts

@@ -0,0 +1,15 @@
+export const createEngineStatusRequestTracker = () => {
+  let nextRequestId = 0;
+  const latestRequestByKind = new Map<string, number>();
+
+  return {
+    begin(kind: string): number {
+      const requestId = ++nextRequestId;
+      latestRequestByKind.set(kind, requestId);
+      return requestId;
+    },
+    isCurrent(kind: string, requestId: number): boolean {
+      return latestRequestByKind.get(kind) === requestId;
+    }
+  };
+};

src/utils/logEntries.test.ts

@@ -61,6 +61,19 @@ describe('log entry streaming', () => {
     ).map(item => item.message)).toEqual(['one', 'repeat', 'three', 'repeat', 'four']);
   });
 
+  it('deduplicates a persisted line and its differently formatted live event', () => {
+    const snapshot = [persistedLogEntry('[2026-07-10][18:00:00][INFO][firelink] repeat')];
+    const live = [liveLogEntry(3, 'repeat', new Date('2026-07-10T14:30:00Z'))];
+
+    expect(mergeLogSnapshotAndLiveEntries(snapshot, live)).toEqual(snapshot);
+  });
+
+  it('preserves compact JSON delimiters while redacting URL queries', () => {
+    const redacted = redactLogText('{"url":"https://example.com/file?token=secret","next":1}');
+
+    expect(redacted).toBe('{"url":"https://example.com/file?[redacted]","next":1}');
+  });
+
   it('bounds burst updates to the newest entries', () => {
     expect(appendBoundedLogEntries(
       [entry('old')],

src/utils/logEntries.ts

@@ -37,27 +37,34 @@ export const redactLogText = (message: string, homePath = ''): string => {
   }
 
   redacted = redacted.replace(
-    /(["'])(authorization|proxy-authorization|cookie|set-cookie|password|token|secret|credential|pairing[-_ ]?token|api[-_ ]?key)(["'])(\s*[:=]\s*)["'][^"\r\n,;]*["']/gi,
-    '$1$2$3$4[redacted]'
-  );
-  redacted = redacted.replace(
-    /([A-Za-z][A-Za-z0-9+.-]*:\/\/)[^@\s/?#]+@/g,
-    '$1[redacted]@'
-  );
-  redacted = redacted.replace(
-    /([A-Za-z][A-Za-z0-9+.-]*:\/\/[^\s?]+)\?[^\s]+/g,
+    /([A-Za-z][A-Za-z0-9+.-]*:\/\/[^\s?"'<>},\]]+)\?[^\s"'<>},\]]+/g,
     '$1?[redacted]'
   );
   redacted = redacted.replace(
     /([A-Za-z][A-Za-z0-9+.-]*:\/\/[^\s?#]+)#\S+/g,
     '$1#[redacted]'
   );
+  redacted = redacted.replace(
+    /([A-Za-z][A-Za-z0-9+.-]*:\/\/)[^@\s/?#]+@/g,
+    '$1[redacted]@'
+  );
+  redacted = redacted.replace(
+    /(["'])(authorization|proxy-authorization|cookie|set-cookie|password|token|secret|credential|pairing[-_ ]?token|api[-_ ]?key)(["'])(\s*[:=]\s*)["'][^"\r\n,;]*["']/gi,
+    '$1$2$3$4[redacted]'
+  );
   return redacted.replace(
     /(authorization|proxy-authorization|cookie|set-cookie|password|token|secret|credential|pairing[-_ ]?token|api[-_ ]?key)(\s*)([:=])(\s*)([^\r\n,;]+)/gi,
     '$1$2$3$4[redacted]'
   );
 };
 
+const mergeKey = (entry: LogEntry): string => {
+  const message = entry.message
+    .replace(/^\[\d{4}-\d{2}-\d{2}\]\[\d{2}:\d{2}:\d{2}\]\[[A-Z]+\](?:\[[^\]]+\])?\s*/, '')
+    .replace(/^\[\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\]\s*\[[A-Z]+\]\s*/, '');
+  return `${entry.level}:${message}`;
+};
+
 export const liveLogEntry = (
   numericLevel: number,
   message: string,
@@ -113,7 +120,7 @@ export const mergeLogSnapshotAndLiveEntries = (
     const snapshotStart = snapshot.length - candidate;
     let matches = true;
     for (let index = 0; index < candidate; index += 1) {
-      if (snapshot[snapshotStart + index].message !== liveEntries[index].message) {
+      if (mergeKey(snapshot[snapshotStart + index]) !== mergeKey(liveEntries[index])) {
         matches = false;
         break;
       }

src/utils/schedulerControl.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from 'vitest';
-import { beginSchedulerControl, isSchedulerControlCurrent } from './schedulerControl';
+import {
+  beginSchedulerControl,
+  consumeSchedulerHandoffIds,
+  handoffSupersededSchedulerIds,
+  isSchedulerControlCurrent
+} from './schedulerControl';
 
 describe('scheduler control generation', () => {
   it('invalidates an older asynchronous scheduler operation', () => {
@@ -10,4 +15,23 @@ describe('scheduler control generation', () => {
     expect(isSchedulerControlCurrent(first)).toBe(false);
     expect(isSchedulerControlCurrent(second)).toBe(true);
   });
+
+  it('hands superseded starts to a newer run for the same queue', () => {
+    const first = beginSchedulerControl(['queue-a']);
+    const second = beginSchedulerControl(['queue-a']);
+
+    expect(handoffSupersededSchedulerIds(['download-a', 'download-b'], id => (
+      id === 'download-a' ? 'queue-a' : 'queue-b'
+    ))).toEqual(new Set(['download-a']));
+    expect(consumeSchedulerHandoffIds(second)).toEqual(new Set(['download-a']));
+    expect(consumeSchedulerHandoffIds(first)).toEqual(new Set());
+  });
+
+  it('does not hand work to a superseding pause control', () => {
+    beginSchedulerControl(['queue-a']);
+    const pause = beginSchedulerControl();
+
+    expect(handoffSupersededSchedulerIds(['download-a'], () => 'queue-a')).toEqual(new Set());
+    expect(consumeSchedulerHandoffIds(pause)).toEqual(new Set());
+  });
 });

src/utils/schedulerControl.ts

@@ -1,14 +1,46 @@
 let schedulerControlGeneration = 0;
+let latestRunQueueIds: ReadonlySet<string> | null = null;
+const schedulerHandoffs = new Map<number, Set<string>>();
 
 /**
  * Start a new scheduler control lifecycle. A later manual pause or scheduler
  * event invalidates earlier asynchronous queue operations before they can
  * publish stale running state.
  */
-export const beginSchedulerControl = (): number => {
+export const beginSchedulerControl = (runQueueIds?: readonly string[]): number => {
   schedulerControlGeneration += 1;
+  latestRunQueueIds = runQueueIds ? new Set(runQueueIds) : null;
+  schedulerHandoffs.clear();
+  if (runQueueIds) schedulerHandoffs.set(schedulerControlGeneration, new Set());
   return schedulerControlGeneration;
 };
 
 export const isSchedulerControlCurrent = (generation: number): boolean =>
   schedulerControlGeneration === generation;
+
+/**
+ * A superseded start may have admitted work before a newer start reached the
+ * same queue. Hand the IDs to that newer start instead of pausing its work.
+ * A stop/manual control has no run intent and therefore receives no handoff.
+ */
+export const handoffSupersededSchedulerIds = (
+  ids: readonly string[],
+  queueIdForId: (id: string) => string | undefined,
+): ReadonlySet<string> => {
+  if (!latestRunQueueIds || schedulerControlGeneration === 0) return new Set();
+  const handoff = schedulerHandoffs.get(schedulerControlGeneration);
+  if (!handoff) return new Set();
+
+  for (const id of ids) {
+    const queueId = queueIdForId(id);
+    if (queueId && latestRunQueueIds.has(queueId)) handoff.add(id);
+  }
+  return new Set(handoff);
+};
+
+export const consumeSchedulerHandoffIds = (generation: number): ReadonlySet<string> => {
+  if (!isSchedulerControlCurrent(generation)) return new Set();
+  const handoff = schedulerHandoffs.get(generation) ?? new Set<string>();
+  schedulerHandoffs.delete(generation);
+  return new Set(handoff);
+};