openchamber/RIGHT_SIDEBAR_PERF_PLAN.md

Right Sidebar Performance Plan

Status — DONE (PR #1674)

P0 — Correctness / leak fixes

• RightSidebar: drop dead useEffect that re-nulled refs the resize handler already nulled; collapse redundant width/minWidth/maxWidth triple into width + the existing --oc-right-sidebar-width variable.
• useUIStore: clamp setRightSidebarWidth to [MIN, MAX]; simplify setRightSidebarOpen (22 lines → 12).
• RightSidebarTabs / useRightSidebarGitSync: takes right tab + main tab; only polls when the right git tab is the visible consumer AND the browser is online + visible. Replaces a poll that ran for the lifetime of any open sidebar.
• GitView: commit-files fetch refactored to cancelled + Promise.all (was a per-hash loop that could setState after unmount); getRemoteUrl and refreshRemotes gated on cancelled / mountedRef; new module-scoped mountedRef guards setIsSettingIdentity from firing after unmount.
• GitView + useGitmojiList: extract gitmoji fetch/cache into a hook with module-level inflight promise + subscribers Set; stale-while-revalidate from localStorage; ensureLoaded() for call-site-initiated hydration; cancelled flag on setIsLoading to avoid the React setState-after-unmount race.
• ProjectNotesTodoPanel: 400 ms notes debounce now cancels on blur (was double-saving); persistProjectData chained per project through a module-level Map<projectId, Promise> so a fast todo toggle racing the debounced save no longer hits the server in parallel; resize auto-adjust guards against same-value pings.

P1 — Render fanout

• RightSidebarTabs: all three tab content components now always mounted with the hidden attribute. State and cache survive tab switches. When activeMainTab === 'git' (or 'context') the matching right tab is filtered out of the tab strip and a redirect effect snaps any persisted-but-now-hidden right tab to 'files'. onSelect is now a type-guarded handler instead of as RightTab.
• GitView: 13 separate useGitStore action selectors collapsed into one useShallow block (one re-evaluation per store change instead of 13).
• GitView: new isGitViewActive flag (true when this instance is the visible consumer) gates the 7 live effects — load identities, fetch remote URL, refresh remotes, ensureAll, sessionEvents.onGitRefreshHint, worktree bootstrap poll, default-identity auto-apply. Hidden GitView instances no longer run these.
• GitView: gitViewSnapshots module-level Map is now backed by an LRU wrapper (cap 20) so per-directory draft snapshots cannot leak across hundreds of project switches. Removed the dead unique.set dedup in changeEntries — GitStatus.files is already unique by path.
• SidebarFilesTree: statusByPath Map<path, FileStatus> and badgeByDir Map<dirPath, { modified, added }> are precomputed once per gitStatus change. Tree render is O(1) per node instead of O(N) per node. badgeByDir walks each file's path segments and increments counters for every ancestor dir.
• SidebarFilesTree: FileRow wrapped in React.memo with a custom comparator. Context-menu open state moved INTO FileRow as local state — opening a menu in one row no longer re-renders siblings.
• SidebarFilesTree: loadDirectory accepts an isCancelled predicate; the batch-load effect for expandedPaths passes a stable predicate so per-dir fetches stop touching state once the effect tears down.
• SidebarFilesTree: module-level fileTreeCacheByRoot Map (LRU, cap 8 roots) hydrates childrenByDir / loadErrorsByDir / loadedDirsRef on mount or root change. Mirror effects write state back to the cache. Survives close-and-reopen of the right sidebar.

Review fixes (post-review)

• Blocker: inFlightDirsRef leak — removed isCancelled guard from finally so inflight flag always cleans up. Re-expanding a cancelled directory correctly retries.
• Non-blocker: duplicate RIGHT_SIDEBAR_MAX_WIDTH — exported from useUIStore, imported in RightSidebar. Single source of truth.
• Non-blocker: useRightSidebarGitSync poll gating — verified shouldPoll already includes rightTab === 'git'. No code change needed.

Files modified

File	Change
packages/ui/src/components/layout/RightSidebar.tsx	Drop dead useEffect, collapse width props, import constants from store
packages/ui/src/components/layout/RightSidebarTabs.tsx	Always-mount tabs, gated poll, redirect effect, type-guarded onSelect
packages/ui/src/components/layout/SidebarFilesTree.tsx	Precomputed maps, React.memo(FileRow), isCancelled predicate, LRU cache
packages/ui/src/components/git/GitView.tsx	Cancelled + Promise.all, isGitViewActive, useShallow, LRU snapshots
packages/ui/src/components/project/ProjectNotesTodoPanel.tsx	Debounce cancel on blur, chained persistProjectData
packages/ui/src/stores/useUIStore.ts	Clamp setRightSidebarWidth, simplify setRightSidebarOpen, export constants
packages/ui/src/hooks/useGitmojiList.ts	New — module-level inflight + subscribers, localStorage cache

Architecture notes

• The redirect effect snaps rightSidebarTab to 'files' whenever activeMainTab === 'git', so the right and main GitView instances are mutually exclusive — isGitViewActive cannot be true for both.
• The 7 gated effects plus the useRightSidebarGitSync poll cover all cases where git state should advance: visible consumer fetches; the poll keeps the store warm when only the right git tab is visible.
• The loadDirectory cancellation predicate prevents stale state writes in try/catch; the finally block always cleans up inFlightDirsRef.

Out of scope (deferred)

• Virtualization of SidebarFilesTree (large refactor; current precomputed maps already address the main bottlenecks).
• Lazy plan titles (requires openchamberConfig schema changes).
• Extracting remaining sub-views from GitView (large refactor, not perf-critical).