bench: add vitest benchmarks for diff, display lines, and TUI rendering

bench/buildDisplayLines.bench.ts

@@ -0,0 +1,117 @@
+import type { Difference } from "@aws-sdk/client-codecommit";
+import { bench, describe } from "vitest";
+import type { CommentThread } from "../src/services/codecommit.js";
+import { buildDisplayLines, type DisplayLine } from "../src/utils/displayLines.js";
+
+function makeLines(count: number, prefix: string): string {
+  return Array.from({ length: count }, (_, i) => `${prefix} line ${i} with some content`).join(
+    "\n",
+  );
+}
+
+function makeFixture(fileCount: number, linesPerFile: number) {
+  const differences: Difference[] = [];
+  const diffTexts = new Map<string, { before: string; after: string }>();
+  const diffTextStatus = new Map<string, "loading" | "loaded" | "error">();
+
+  for (let f = 0; f < fileCount; f++) {
+    const beforeBlobId = `before-${f}`;
+    const afterBlobId = `after-${f}`;
+    differences.push({
+      beforeBlob: { blobId: beforeBlobId, path: `src/file-${f}.ts` },
+      afterBlob: { blobId: afterBlobId, path: `src/file-${f}.ts` },
+      changeType: "M",
+    });
+    const key = `${beforeBlobId}:${afterBlobId}`;
+    const before = makeLines(linesPerFile, `f${f}-old`);
+    const after = makeLines(linesPerFile, `f${f}-new`);
+    diffTexts.set(key, { before, after });
+    diffTextStatus.set(key, "loaded");
+  }
+
+  return { differences, diffTexts, diffTextStatus };
+}
+
+function makeInlineThreads(fileCount: number, threadsPerFile: number): CommentThread[] {
+  const threads: CommentThread[] = [];
+  for (let f = 0; f < fileCount; f++) {
+    for (let t = 0; t < threadsPerFile; t++) {
+      threads.push({
+        location: {
+          filePath: `src/file-${f}.ts`,
+          filePosition: t * 10 + 1,
+          relativeFileVersion: "AFTER",
+        },
+        comments: [
+          {
+            commentId: `c-${f}-${t}`,
+            content: `comment ${t} on file ${f}`,
+            authorArn: "arn:aws:iam::123456789012:user/reviewer",
+          },
+        ],
+      });
+    }
+  }
+  return threads;
+}
+
+const small = makeFixture(5, 100);
+const large = makeFixture(20, 400);
+const withComments = makeFixture(10, 200);
+const inlineThreads = makeInlineThreads(10, 5);
+
+describe("buildDisplayLines", () => {
+  bench("5 files x 100 lines, no comments, cold cache", () => {
+    buildDisplayLines(
+      small.differences,
+      small.diffTexts,
+      small.diffTextStatus,
+      new Map(),
+      [],
+      new Map(),
+      new Map(),
+      new Map(),
+    );
+  });
+
+  bench("20 files x 400 lines, no comments, cold cache", () => {
+    buildDisplayLines(
+      large.differences,
+      large.diffTexts,
+      large.diffTextStatus,
+      new Map(),
+      [],
+      new Map(),
+      new Map(),
+      new Map(),
+    );
+  });
+
+  const warmCache = new Map<string, DisplayLine[]>();
+  bench("20 files x 400 lines, no comments, warm cache", () => {
+    buildDisplayLines(
+      large.differences,
+      large.diffTexts,
+      large.diffTextStatus,
+      new Map(),
+      [],
+      new Map(),
+      new Map(),
+      warmCache,
+    );
+  });
+
+  const warmCacheComments = new Map<string, DisplayLine[]>();
+  bench("10 files x 200 lines, 50 inline threads, warm cache", () => {
+    buildDisplayLines(
+      withComments.differences,
+      withComments.diffTexts,
+      withComments.diffTextStatus,
+      new Map(),
+      inlineThreads,
+      new Map(),
+      new Map(),
+      warmCacheComments,
+    );
+  });
+});

bench/computeSimpleDiff.bench.ts

@@ -0,0 +1,55 @@
+import { bench, describe } from "vitest";
+import { computeSimpleDiff } from "../src/utils/formatDiff.js";
+
+function makeLines(count: number, prefix: string): string[] {
+  return Array.from({ length: count }, (_, i) => `${prefix} line ${i} with some content`);
+}
+
+// Identical files: pure context path
+const identical2k = makeLines(2000, "same");
+
+// Fully rewritten file: every before-line is deleted, every after-line is added.
+// Worst case for unbounded lookahead scans.
+const rewrittenBefore2k = makeLines(2000, "old");
+const rewrittenAfter2k = makeLines(2000, "new");
+
+// Realistic edit: large file with several small change blocks
+const editedBefore = makeLines(3000, "ctx");
+const editedAfter = (() => {
+  const lines = [...editedBefore];
+  for (let block = 0; block < 10; block++) {
+    const at = 250 + block * 250;
+    lines.splice(at, 5, ...makeLines(8, `edit${block}`));
+  }
+  return lines;
+})();
+
+// Reordered blocks: triggers the 5-line lookahead match path
+const reorderedBefore = makeLines(1000, "blk");
+const reorderedAfter = (() => {
+  const lines = [...reorderedBefore];
+  for (let i = 0; i < lines.length - 3; i += 7) {
+    const tmp = lines[i]!;
+    lines[i] = lines[i + 3]!;
+    lines[i + 3] = tmp;
+  }
+  return lines;
+})();
+
+describe("computeSimpleDiff", () => {
+  bench("identical 2000-line files", () => {
+    computeSimpleDiff(identical2k, identical2k);
+  });
+
+  bench("fully rewritten 2000-line file", () => {
+    computeSimpleDiff(rewrittenBefore2k, rewrittenAfter2k);
+  });
+
+  bench("3000-line file with 10 edit blocks", () => {
+    computeSimpleDiff(editedBefore, editedAfter);
+  });
+
+  bench("1000-line file with reordered blocks", () => {
+    computeSimpleDiff(reorderedBefore, reorderedAfter);
+  });
+});

bench/detailRender.bench.tsx

@@ -0,0 +1,147 @@
+import type { Difference } from "@aws-sdk/client-codecommit";
+import { render } from "ink-testing-library";
+import React from "react";
+import { bench, describe } from "vitest";
+import { PullRequestDetail } from "../src/components/PullRequestDetail.js";
+
+const noop = () => {};
+
+function makeLines(count: number, prefix: string): string {
+  return Array.from({ length: count }, (_, i) => `${prefix} line ${i} with some content`).join(
+    "\n",
+  );
+}
+
+function makeFixture(fileCount: number, linesPerFile: number) {
+  const differences: Difference[] = [];
+  const diffTexts = new Map<string, { before: string; after: string }>();
+  const diffTextStatus = new Map<string, "loading" | "loaded" | "error">();
+
+  for (let f = 0; f < fileCount; f++) {
+    const beforeBlobId = `before-${f}`;
+    const afterBlobId = `after-${f}`;
+    differences.push({
+      beforeBlob: { blobId: beforeBlobId, path: `src/file-${f}.ts` },
+      afterBlob: { blobId: afterBlobId, path: `src/file-${f}.ts` },
+      changeType: "M",
+    });
+    const key = `${beforeBlobId}:${afterBlobId}`;
+    diffTexts.set(key, {
+      before: makeLines(linesPerFile, `f${f}-old`),
+      after: makeLines(linesPerFile, `f${f}-new`),
+    });
+    diffTextStatus.set(key, "loaded");
+  }
+
+  return { differences, diffTexts, diffTextStatus };
+}
+
+const pullRequest = {
+  pullRequestId: "42",
+  title: "perf: benchmark fixture",
+  authorArn: "arn:aws:iam::123456789012:user/watany",
+  pullRequestStatus: "OPEN",
+  creationDate: new Date("2026-02-13T10:00:00Z"),
+  pullRequestTargets: [
+    {
+      destinationReference: "refs/heads/main",
+      sourceReference: "refs/heads/feature/perf",
+    },
+  ],
+};
+
+const asyncActionProps = {
+  onPost: noop,
+  isProcessing: false,
+  error: null,
+  onClearError: noop,
+};
+
+const fixture = makeFixture(10, 200);
+
+function renderDetail() {
+  return render(
+    <PullRequestDetail
+      pullRequest={pullRequest as never}
+      differences={fixture.differences}
+      commentThreads={[]}
+      diffTexts={fixture.diffTexts}
+      diffTextStatus={fixture.diffTextStatus}
+      onBack={noop}
+      onHelp={noop}
+      onShowActivity={noop}
+      comment={asyncActionProps}
+      inlineComment={asyncActionProps}
+      reply={asyncActionProps}
+      approval={{
+        approvals: [],
+        evaluation: null,
+        onApprove: noop,
+        onRevoke: noop,
+        isProcessing: false,
+        error: null,
+        onClearError: noop,
+      }}
+      merge={{
+        onMerge: noop,
+        onCheckConflicts: () =>
+          Promise.resolve({ mergeable: true, conflictCount: 0, conflictFiles: [] }),
+        isProcessing: false,
+        error: null,
+        onClearError: noop,
+      }}
+      close={{ onClose: noop, isProcessing: false, error: null, onClearError: noop }}
+      commitView={{
+        commits: [],
+        differences: [],
+        diffTexts: new Map(),
+        isLoading: false,
+        onLoad: noop,
+        commitsAvailable: false,
+      }}
+      editComment={{ onUpdate: noop, isProcessing: false, error: null, onClearError: noop }}
+      deleteComment={{ onDelete: noop, isProcessing: false, error: null, onClearError: noop }}
+      reaction={{
+        byComment: new Map(),
+        onReact: noop,
+        isProcessing: false,
+        error: null,
+        onClearError: noop,
+      }}
+    />,
+  );
+}
+
+const flush = () => new Promise<void>((r) => setTimeout(r, 0));
+
+describe("PullRequestDetail rendering (10 files x 200 lines)", () => {
+  bench("initial mount + unmount", async () => {
+    const instance = renderDetail();
+    await flush();
+    instance.unmount();
+  });
+
+  // Alternate down/up so the cursor keeps moving (a clamped cursor skips re-render)
+  const navInstance = renderDetail();
+  let navDown = true;
+  bench("j/k keystroke (cursor move + re-render)", async () => {
+    navInstance.stdin.write(navDown ? "j" : "k");
+    navDown = !navDown;
+    await flush();
+  });
+
+  // Unhandled key: measures stdin parsing + flush overhead without a re-render
+  const noopInstance = renderDetail();
+  bench("no-op keystroke (no re-render)", async () => {
+    noopInstance.stdin.write("z");
+    await flush();
+  });
+
+  const pageInstance = renderDetail();
+  let pageDown = true;
+  bench("Ctrl+d/u half-page scroll + re-render", async () => {
+    pageInstance.stdin.write(pageDown ? "\x04" : "\x15");
+    pageDown = !pageDown;
+    await flush();
+  });
+});

build.ts

@@ -21,6 +21,9 @@ const [cliResult, libResult] = await Promise.all([
 		minify: true,
 		naming: "cli.mjs",
 		plugins: [stubDevtools],
+		// Inline NODE_ENV so react-reconciler/react bundle their production
+		// builds instead of deciding at runtime (users rarely set NODE_ENV)
+		define: { "process.env.NODE_ENV": '"production"' },
 	}),
 	Bun.build({
 		entrypoints: ["./src/index.ts"],
@@ -29,6 +32,7 @@ const [cliResult, libResult] = await Promise.all([
 		target: "node",
 		minify: true,
 		plugins: [stubDevtools],
+		define: { "process.env.NODE_ENV": '"production"' },
 	}),
 ]);