Prevent <TasksLayout/> component from being unmounted when using (#1391)

keyboard shortcuts to navigate the kanban board.

In kanban boards with many tasks in a single column, when we use
keyboard shortcuts to select a task 'below the fold', the animation
restarts from the top of the kanban board, rather than preserving the
existing position.

frontend/src/contexts/ExecutionProcessesContext.tsx

@@ -20,7 +20,7 @@ const ExecutionProcessesContext =
   createContext<ExecutionProcessesContextType | null>(null);
 
 export const ExecutionProcessesProvider: React.FC<{
-  attemptId: string;
+  attemptId: string | undefined;
   children: React.ReactNode;
 }> = ({ attemptId, children }) => {
   const {

frontend/src/contexts/ReviewProvider.tsx

@@ -1,5 +1,11 @@
 import { SplitSide } from '@git-diff-view/react';
-import { createContext, useContext, useState, ReactNode } from 'react';
+import {
+  createContext,
+  useContext,
+  useState,
+  ReactNode,
+  useEffect,
+} from 'react';
 import { genId } from '@/utils/id';
 
 export interface ReviewComment {
@@ -40,10 +46,20 @@ export function useReview() {
   return context;
 }
 
-export function ReviewProvider({ children }: { children: ReactNode }) {
+export function ReviewProvider({
+  children,
+  attemptId,
+}: {
+  children: ReactNode;
+  attemptId?: string;
+}) {
   const [comments, setComments] = useState<ReviewComment[]>([]);
   const [drafts, setDrafts] = useState<Record<string, ReviewDraft>>({});
 
+  useEffect(() => {
+    return () => clearComments();
+  }, [attemptId]);
+
   const addComment = (comment: Omit<ReviewComment, 'id'>) => {
     const newComment: ReviewComment = {
       ...comment,

frontend/src/hooks/useExecutionProcesses.ts

@@ -21,15 +21,19 @@ interface UseExecutionProcessesResult {
  * Live updates arrive at /execution_processes/<id> via add/replace/remove operations.
  */
 export const useExecutionProcesses = (
-  taskAttemptId: string,
+  taskAttemptId: string | undefined,
   opts?: { showSoftDeleted?: boolean }
 ): UseExecutionProcessesResult => {
   const showSoftDeleted = opts?.showSoftDeleted;
+  let endpoint: string | undefined;
+
+  if (taskAttemptId) {
     const params = new URLSearchParams({ task_attempt_id: taskAttemptId });
     if (typeof showSoftDeleted === 'boolean') {
       params.set('show_soft_deleted', String(showSoftDeleted));
     }
-  const endpoint = `/api/execution-processes/stream/ws?${params.toString()}`;
+    endpoint = `/api/execution-processes/stream/ws?${params.toString()}`;
+  }
 
   const initialData = useCallback(
     (): ExecutionProcessState => ({ execution_processes: {} }),

frontend/src/pages/ProjectTasks.tsx

@@ -1029,12 +1029,11 @@ export function ProjectTasks() {
 
   const effectiveMode: LayoutMode = selectedSharedTask ? null : mode;
 
-  const attemptArea =
-    attempt && selectedTask ? (
-      <GitOperationsProvider attemptId={attempt.id}>
+  const attemptArea = (
+    <GitOperationsProvider attemptId={attempt?.id}>
       <ClickedElementsProvider attempt={attempt}>
-          <ReviewProvider key={attempt.id}>
-            <ExecutionProcessesProvider key={attempt.id} attemptId={attempt.id}>
+        <ReviewProvider attemptId={attempt?.id}>
+          <ExecutionProcessesProvider attemptId={attempt?.id}>
             <TasksLayout
               kanban={kanbanContent}
               attempt={attemptContent}
@@ -1048,16 +1047,6 @@ export function ProjectTasks() {
         </ReviewProvider>
       </ClickedElementsProvider>
     </GitOperationsProvider>
-    ) : (
-      <TasksLayout
-        kanban={kanbanContent}
-        attempt={attemptContent}
-        aux={auxContent}
-        isPanelOpen={isPanelOpen}
-        mode={effectiveMode}
-        isMobile={isMobile}
-        rightHeader={rightHeader}
-      />
   );
 
   return (