perf(agent-manager): optimize worktree diff loading

[marius-kilocode]

Summary

Agent Manager worktree review switching rebuilt the entire diff surface and repeated Git work for every detail request. This change retains recently rendered review panels and removes redundant work from the extension-host diff path, while preserving the stacked review UX, complete file loading, comments, Markdown rendering, image handling, and live polling.

Performance

Measurements were collected with the VS Code self-test harness against an ephemeral shadow/fixture workspace containing real worktree diffs. The same Agent Manager surface, worktree cards, and completion checks were used for before/after captures where the worktree remained stable.

Scenario	Before	After	Change
Cold seven-file diff, fully rendered	942 ms	480 ms	49% faster, about 2.0x
Warm A-B-A switch, complete rendered diff	144-169 ms	about 46 ms	68-73% faster, about 3.1-3.7x
Warm diff DOM churn	4,678 nodes	117 nodes	97.5% lower
Warm switch heap allocation	9.3 MB	3.1 MB	about 67% lower
Heavy render script time	390 ms	163 ms	about 58% lower
Largest heavy render task	249 ms	116 ms	about 54% shorter
Animated loading states	Present	None	Removed

The original heavy worktree changed while its owning Agent Manager session was active, so later heavy cold captures are not byte-identical. The final cold seven-file capture is therefore the conservative cold comparison. The warm measurement directly verified the retained DOM, no loading state, no spinner, complete diff hosts, and scroll preservation.

Behavior

• Retains up to four recent project-and-scope-qualified diff panels without unmounting their Virtua/Pierre state.
• Preserves expanded files and scroll position across worktree switches.
• Keeps comments and review composers isolated by project and composite diff scope.
• Reuses summary metadata and caches exact file details with bounded count and byte limits.
• Cancels queued and running obsolete Git detail processes when switching contexts.
• Prevents overlapping diff polling fetches.
• Removes animated summary and per-file loading spinners.
• Keeps large-file limits, hunk-bounded patches, untracked files, images, Markdown rendering, and live stale-detail refresh behavior unchanged.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 file)

• packages/kilo-vscode/src/agent-manager/local-diff.ts

Previous Review Summaries (7 snapshots, latest commit bf07f65)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit bf07f65)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 file)

• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx

Previous review (commit 7230c71)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 file)

• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx

Previous review (commit 71211f1)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• packages/kilo-vscode/src/agent-manager/semaphore.ts
• packages/kilo-vscode/src/diff/SourceController.ts
• packages/kilo-vscode/webview-ui/agent-manager/worktree-diffs.ts

Previous review (commit 5fea23b)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (6 files)

• packages/kilo-vscode/src/agent-manager/local-diff.ts
• packages/kilo-vscode/src/diff/SourceController.ts
• packages/kilo-vscode/tests/unit/source-controller.test.ts
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx
• packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx
• packages/kilo-vscode/webview-ui/agent-manager/worktree-diffs.ts

Previous review (commit befab09)

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Previous review (commit befab09)

Status: 4 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	4
SUGGESTION	0

Issue Details (click to expand)

WARNING

File	Line	Issue
packages/kilo-vscode/webview-ui/agent-manager/worktree-diffs.ts	158	Merge reads project() but writes ev.projectId
packages/kilo-vscode/src/agent-manager/local-diff.ts	362	Cache hits re-read and hash the entire working file
packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx	163	Activating a cached panel can wipe a shared composer draft
packages/kilo-vscode/src/diff/SourceController.ts	271	Coalesced fetches can skip the post-revert refresh

Files Reviewed (15 files)

• packages/kilo-vscode/src/agent-manager/local-diff.ts - 1 issue
• packages/kilo-vscode/src/diff/SourceController.ts - 1 issue
• packages/kilo-vscode/tests/unit/agent-manager-worktree-diffs.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/git-ops.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/local-diff.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/source-controller.test.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx - 1 issue
• packages/kilo-vscode/webview-ui/agent-manager/DiffPanelCache.tsx - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/apply-to-local.tsx - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/project/review-state.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/revert-file.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/review-composers.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/worktree-diffs.ts - 1 issue
• packages/kilo-vscode/webview-ui/diff-viewer/diff-requests.ts - 0 issues

Fix these issues in Kilo Cloud

Previous review (commit ea74bda)

Status: 4 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	3
SUGGESTION	1

Issue Details (click to expand)

WARNING

File	Line	Issue
packages/kilo-vscode/src/agent-manager/local-diff.ts	328	Aborted/failed detail fetches can be cached as empty diffs
packages/kilo-vscode/webview-ui/diff-viewer/diff-requests.ts	39	Warm switch-back does not retry cancelled detail requests
packages/kilo-vscode/webview-ui/agent-manager/DiffPanelCache.tsx	94	Inactive cached panels can clobber the shared review composer

SUGGESTION

File	Line	Issue
packages/kilo-vscode/webview-ui/agent-manager/review-composers.ts	15	clear() is never called, so composers grow without bound

Files Reviewed (21 files)

• .changeset/fast-agent-manager-diffs.md - 0 issues
• packages/kilo-vscode/src/agent-manager/AgentManagerProvider.ts - 0 issues
• packages/kilo-vscode/src/agent-manager/GitOps.ts - 0 issues
• packages/kilo-vscode/src/agent-manager/local-diff.ts - 1 issue
• packages/kilo-vscode/src/agent-manager/semaphore.ts - 0 issues
• packages/kilo-vscode/src/diff/SourceController.ts - 0 issues
• packages/kilo-vscode/src/diff/sources/catalog.ts - 0 issues
• packages/kilo-vscode/src/diff/sources/worktree.ts - 0 issues
• packages/kilo-vscode/tests/unit/agent-manager-arch.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/agent-manager-worktree-diffs.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/local-diff.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/semaphore.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/source-controller.test.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/DiffPanelCache.tsx - 1 issue
• packages/kilo-vscode/webview-ui/agent-manager/agent-manager.css - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/revert-file.ts - 0 issues
• packages/kilo-vscode/webview-ui/agent-manager/review-composers.ts - 1 issue
• packages/kilo-vscode/webview-ui/agent-manager/worktree-diffs.ts - 0 issues
• packages/kilo-vscode/webview-ui/diff-viewer/diff-requests.ts - 1 issue

Fix these issues in Kilo Cloud

---

_{Reviewed by grok-4.6 · Input: 131K · Output: 10.7K · Cached: 215.3K}

_{Review guidance: REVIEW.md from base branch main}

[marius-kilocode]

thanks @WebReflection

[iscekic]

Approved, ignorable bot remarks below

[marius-kilocode]

Updated performance results

The latest optimization replaces two separate tracked-file scans, git diff --name-status and git diff --numstat, with one git diff --raw --numstat command. This removes a full repository scan and reduces contention in the shared Git process queue without changing diff content, file statuses, line counts, images, or review behavior.

Measured in the same isolated VS Code instance against the same 12-file worktree, with a cold extension process and all file details loaded:

Metric	Before	After	Improvement
Diff summary available	556 ms	350 ms	37% faster
All 12 file details loaded	1,200 ms	574 ms	52% faster
Diff panel first visible	9 ms	8 ms	No meaningful change
Renderer JavaScript	62 ms	56 ms	Not the main bottleneck
Git summary subprocesses	4	3	One fewer full Git scan

The earlier figures in the PR description used a different seven-file scenario: 942 ms to 480 ms cold, and 144-169 ms to about 46 ms for warm A-B-A switching. The new 12-file measurements are a separate before/after comparison for the additional Git-scan optimization, not a direct replacement for that seven-file baseline.

Warm cached panel reopening remains approximately 4 ms. The remaining cold-load cost is primarily the separate per-file Git detail operations; batching those requests is tracked in #13415.

Validation: all 4,153 extension unit tests pass, along with lint, both typechecks, Knip, and manual verification of complete diff rendering and warm worktree switching.