fix: pr-bug-scan validated finding from #2793 (#3024)

Co-authored-by: orca-bug-scan-bot <orca-bug-scan-bot@stably.ai>
Co-authored-by: Neil <4138956+nwparker@users.noreply.github.com>

src/renderer/src/components/right-sidebar/FileExplorer.tsx

@@ -8,6 +8,7 @@ import { folderRelativePathToIncludeGlob } from './file-search-include-pattern'
 import { ScrollArea } from '@/components/ui/scroll-area'
 import { cn } from '@/lib/utils'
 import { isGitRepoKind } from '../../../../shared/repo-kind'
+import { shouldResetFileExplorerForVisibleWorktree } from './file-explorer-reset'
 import { FileExplorerBackgroundMenu } from './FileExplorerBackgroundMenu'
 import { FileExplorerToolbar } from './FileExplorerToolbar'
 import { FileExplorerTreeStatus } from './FileExplorerTreeStatus'
@@ -157,12 +158,22 @@ function FileExplorerInner(): React.JSX.Element {
     scrollRef
   })
 
+  const lastResetWorktreePathRef = useRef<string | null>(null)
   useEffect(() => {
     if (!visibleWorktreePath) {
       return
     }
     // Why: the sidebar remains mounted while closed to preserve caches, but
     // loading the hidden tree would probe every clicked workspace on macOS.
+    if (
+      !shouldResetFileExplorerForVisibleWorktree(
+        lastResetWorktreePathRef.current,
+        visibleWorktreePath
+      )
+    ) {
+      return
+    }
+    lastResetWorktreePathRef.current = visibleWorktreePath
     resetSelection()
     resetAndLoad()
     clearFileExplorerUndoHistory()

src/renderer/src/components/right-sidebar/file-explorer-reset.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest'
+import { shouldResetFileExplorerForVisibleWorktree } from './file-explorer-reset'
+
+describe('shouldResetFileExplorerForVisibleWorktree', () => {
+  it('preserves explorer state across hide and reopen of the same worktree', () => {
+    let lastResetWorktreePath: string | null = null
+    const shouldReset = (visibleWorktreePath: string | null): boolean => {
+      if (shouldResetFileExplorerForVisibleWorktree(lastResetWorktreePath, visibleWorktreePath)) {
+        lastResetWorktreePath = visibleWorktreePath
+        return true
+      }
+      return false
+    }
+
+    expect(shouldReset(null)).toBe(false)
+    expect(shouldReset('/repo')).toBe(true)
+    expect(shouldReset(null)).toBe(false)
+    expect(shouldReset('/repo')).toBe(false)
+  })
+
+  it('resets when the visible worktree path changes', () => {
+    expect(shouldResetFileExplorerForVisibleWorktree('/repo', '/repo-next')).toBe(true)
+  })
+})

src/renderer/src/components/right-sidebar/file-explorer-reset.ts

@@ -0,0 +1,6 @@
+export function shouldResetFileExplorerForVisibleWorktree(
+  lastResetWorktreePath: string | null,
+  visibleWorktreePath: string | null
+): visibleWorktreePath is string {
+  return visibleWorktreePath !== null && lastResetWorktreePath !== visibleWorktreePath
+}