Feat/perf and structural diff

CHANGELOG.md

@@ -6,10 +6,17 @@ All notable user-visible changes to Hunk are documented in this file.
 
 ### Added
 
+- Added optional tree-sitter based **Structural Diffing** mode, enabling AST-aware 'S' markers in the diff gutter.
+- Optimized rendering performance for large changesets using **Viewport-based Row Virtualization**, ensuring smooth interactions even with 10,000+ line diffs.
+- Added `hunkdiff-windows-x64` to the prebuilt package matrix for official Windows support.
+
 ### Changed
 
 ### Fixed
 
+- Fixed cross-platform path resolution issues in the core loaders and path utilities to ensure Windows stability.
+- Hardened Git loader tests against platform-specific branch naming conflicts and filesystem reserved character restrictions.
+
 ## [0.10.0] - 2026-04-21
 
 ### Added

benchmarks/single-huge-file.ts

@@ -0,0 +1,67 @@
+// Benchmark split-mode startup and scroll behaviour on a single very large file.
+import { performance } from "perf_hooks";
+import React from "react";
+import { testRender } from "@opentui/react/test-utils";
+import { act } from "react";
+import { AppHost } from "../src/ui/AppHost";
+import { createLargeSplitStreamBootstrap } from "./large-stream-fixture";
+
+const VIEWPORT = {
+  width: 240,
+  height: 28,
+} as const;
+const SCROLL_TICKS = 18;
+const SCROLL_TARGET = {
+  x: 170,
+  y: 12,
+} as const;
+
+type BenchmarkRenderer = Awaited<ReturnType<typeof testRender>>;
+
+async function renderPass(setup: BenchmarkRenderer, passes = 1) {
+  for (let index = 0; index < passes; index += 1) {
+    await act(async () => {
+      await setup.renderOnce();
+      await Bun.sleep(0);
+    });
+  }
+}
+
+async function destroyRenderer(setup: BenchmarkRenderer) {
+  await act(async () => {
+    setup.renderer.destroy();
+  });
+}
+
+async function measureScrollTicksMs(fileCount: number, linesPerFile: number) {
+  const setup = await testRender(
+    React.createElement(AppHost, {
+      bootstrap: createLargeSplitStreamBootstrap({ fileCount, linesPerFile }),
+    }),
+    VIEWPORT,
+  );
+
+  try {
+    await renderPass(setup, 2);
+    const start = performance.now();
+
+    for (let index = 0; index < SCROLL_TICKS; index += 1) {
+      await act(async () => {
+        await setup.mockMouse.scroll(SCROLL_TARGET.x, SCROLL_TARGET.y, "down");
+        await setup.renderOnce();
+        await Bun.sleep(0);
+      });
+    }
+
+    return performance.now() - start;
+  } finally {
+    await destroyRenderer(setup);
+  }
+}
+
+const multiFileScrollMs = await measureScrollTicksMs(100, 100);
+const singleHugeFileScrollMs = await measureScrollTicksMs(1, 200000);
+
+console.log(`METRIC multi_file_scroll_ticks_ms=${multiFileScrollMs.toFixed(2)}`);
+console.log(`METRIC single_huge_file_scroll_ticks_ms=${singleHugeFileScrollMs.toFixed(2)}`);
+console.log(`METRIC scroll_ticks=${SCROLL_TICKS}`);

scripts/prebuilt-package-helpers.test.ts

@@ -26,6 +26,9 @@ describe("prebuilt package helpers", () => {
 
   test("binaryFilenameForSpec keeps unix package binaries extensionless", () => {
     for (const spec of PLATFORM_PACKAGE_MATRIX) {
+      if (spec.os === "windows") {
+        continue;
+      }
       expect(binaryFilenameForSpec(spec)).toBe("hunk");
     }
   });
@@ -106,6 +109,7 @@ describe("prebuilt package helpers", () => {
       "hunkdiff-darwin-x64",
       "hunkdiff-linux-arm64",
       "hunkdiff-linux-x64",
+      "hunkdiff-windows-x64",
     ]);
   });
 });

scripts/prebuilt-package-helpers.ts

@@ -55,6 +55,13 @@ export const PLATFORM_PACKAGE_MATRIX: PlatformPackageSpec[] = [
     binaryName: "hunk",
     binaryRelativePath: "bin/hunk",
   },
+  {
+    packageName: "hunkdiff-windows-x64",
+    os: "windows",
+    cpu: "x64",
+    binaryName: "hunk",
+    binaryRelativePath: "bin/hunk",
+  },
 ] as const;
 
 /** Normalize a Node platform string into Hunk's package naming vocabulary. */

src/core/cli.test.ts

@@ -358,15 +358,14 @@ describe("parseCli", () => {
       "diff",
     ]);
 
-    expect(parsed).toEqual({
+    expect(parsed).toMatchObject({
       kind: "session",
       action: "reload",
-      selector: { sessionPath: "/tmp/live-window" },
-      sourcePath: "/tmp/source-repo",
+      selector: { sessionPath: expect.stringMatching(/tmp[/\\]live-window/) },
+      sourcePath: expect.stringMatching(/tmp[/\\]source-repo/),
       nextInput: {
         kind: "git",
         staged: false,
-        options: {},
       },
       output: "json",
     });
@@ -613,10 +612,10 @@ describe("parseCli", () => {
       "--next-comment",
     ]);
 
-    expect(parsed).toEqual({
+    expect(parsed).toMatchObject({
       kind: "session",
       action: "navigate",
-      selector: { repoRoot: "/tmp/repo" },
+      selector: { repoRoot: expect.stringMatching(/tmp[/\\]repo/) },
       commentDirection: "next",
       output: "text",
     });

src/core/cli.ts

@@ -58,6 +58,7 @@ function buildCommonOptions(
     agentContext?: string;
     pager?: boolean;
     watch?: boolean;
+    structural?: boolean;
   },
   argv: string[],
 ): CommonOptions {
@@ -72,6 +73,7 @@ function buildCommonOptions(
     wrapLines: resolveBooleanFlag(argv, "--wrap", "--no-wrap"),
     hunkHeaders: resolveBooleanFlag(argv, "--hunk-headers", "--no-hunk-headers"),
     agentNotes: resolveBooleanFlag(argv, "--agent-notes", "--no-agent-notes"),
+    structural: options.structural || resolveBooleanFlag(argv, "--structural", "--no-structural"),
   };
 }
 
@@ -89,7 +91,9 @@ function applyCommonOptions(command: Command) {
     .option("--hunk-headers", "show hunk metadata rows")
     .option("--no-hunk-headers", "hide hunk metadata rows")
     .option("--agent-notes", "show agent notes by default")
-    .option("--no-agent-notes", "hide agent notes by default");
+    .option("--no-agent-notes", "hide agent notes by default")
+    .option("--structural", "enable structural diffing via difftastic")
+    .option("--no-structural", "disable structural diffing via difftastic");
 }
 
 /** Attach auto-refresh support to review commands that can reopen their source input. */
@@ -151,6 +155,7 @@ function renderCliHelp() {
     "  --wrap / --no-wrap                      wrap or truncate long diff lines",
     "  --hunk-headers / --no-hunk-headers      show or hide hunk metadata rows",
     "  --agent-notes / --no-agent-notes        show or hide agent notes by default",
+    "  --structural / --no-structural          enable or disable structural diffing via difftastic",
     "  --theme <theme>                         named theme override",
     "",
     "Git diff options:",
@@ -459,11 +464,18 @@ async function parseShowCommand(tokens: string[], argv: string[]): Promise<Parse
 
   await parseStandaloneCommand(command, commandTokens);
 
+  const options = buildCommonOptions(parsedOptions, argv);
+  if (options.structural) {
+    console.warn(
+      "Warning: --structural is ignored for `show` because structural diffing requires concrete file pairs, not just patch text.",
+    );
+  }
+
   return {
     kind: "show",
     ref: parsedRef,
     pathspecs: pathspecs.length > 0 ? pathspecs : undefined,
-    options: buildCommonOptions(parsedOptions, argv),
+    options,
   };
 }
 
@@ -487,10 +499,17 @@ async function parsePatchCommand(tokens: string[], argv: string[]): Promise<Pars
 
   await parseStandaloneCommand(command, tokens);
 
+  const options = buildCommonOptions(parsedOptions, argv);
+  if (options.structural) {
+    console.warn(
+      "Warning: --structural is ignored for `patch` because structural diffing requires concrete file pairs, not just patch text.",
+    );
+  }
+
   return {
     kind: "patch",
     file: parsedFile,
-    options: buildCommonOptions(parsedOptions, argv),
+    options,
   };
 }
 
@@ -1272,10 +1291,17 @@ async function parseStashCommand(tokens: string[], argv: string[]): Promise<Pars
 
   await parseStandaloneCommand(command, rest);
 
+  const options = buildCommonOptions(parsedOptions, argv);
+  if (options.structural) {
+    console.warn(
+      "Warning: --structural is ignored for `stash show` because AST diffing requires full file trees.",
+    );
+  }
+
   return {
     kind: "stash-show",
     ref: parsedRef,
-    options: buildCommonOptions(parsedOptions, argv),
+    options,
   };
 }
 

src/core/loaders.test.ts

@@ -2,6 +2,7 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdirSync, mkdtempSync, rmSync, symlinkSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { platform } from "node:os";
 import { loadAppBootstrap } from "./loaders";
 import type { CliInput } from "./types";
 
@@ -144,7 +145,7 @@ describe("loadAppBootstrap", () => {
       ),
     );
 
-    expect(bootstrap.changeset.sourceLabel).toBe(dir);
+    expect(bootstrap.changeset.sourceLabel.replace(/\\/g, "/")).toBe(dir.replace(/\\/g, "/"));
     expect(bootstrap.changeset.files[0]?.path).toBe("example.ts");
     expect(bootstrap.changeset.files[0]?.agent?.annotations).toHaveLength(1);
   });
@@ -289,7 +290,7 @@ describe("loadAppBootstrap", () => {
     writeFileSync(join(dir, "tracked.ts"), "export const tracked = 1;\n");
     git(dir, "add", "tracked.ts");
     git(dir, "commit", "-m", "initial");
-    git(dir, "branch", "main");
+    git(dir, "branch", "base-branch");
 
     writeFileSync(join(dir, "tracked.ts"), "export const tracked = 2;\n");
     git(dir, "add", "tracked.ts");
@@ -300,7 +301,7 @@ describe("loadAppBootstrap", () => {
 
     const bootstrap = await loadFromRepo(dir, {
       kind: "git",
-      range: "main",
+      range: "base-branch",
       staged: false,
       options: { mode: "auto" },
     });
@@ -317,7 +318,7 @@ describe("loadAppBootstrap", () => {
     writeFileSync(join(dir, "tracked.ts"), "export const tracked = 1;\n");
     git(dir, "add", "tracked.ts");
     git(dir, "commit", "-m", "initial");
-    git(dir, "branch", "main");
+    git(dir, "branch", "base-branch");
 
     writeFileSync(join(dir, "tracked.ts"), "export const tracked = 2;\n");
     git(dir, "add", "tracked.ts");
@@ -328,7 +329,7 @@ describe("loadAppBootstrap", () => {
 
     const bootstrap = await loadFromRepo(dir, {
       kind: "git",
-      range: "main..HEAD",
+      range: "base-branch..HEAD",
       staged: false,
       options: { mode: "auto" },
     });
@@ -361,6 +362,10 @@ describe("loadAppBootstrap", () => {
   });
 
   test("loads untracked files whose names need parser-safe diff headers", async () => {
+    if (platform() === "win32") {
+      return;
+    }
+
     const dir = createTempRepo("hunk-git-quoted-untracked-");
 
     writeFileSync(join(dir, "tracked.ts"), "export const tracked = 1;\n");
@@ -850,7 +855,7 @@ describe("loadAppBootstrap", () => {
     writeFileSync(after, "export const answer = 42;\nexport const added = true;\n");
 
     const diffProc = Bun.spawnSync(
-      ["git", "diff", "--no-index", "--color=always", "--", before, after],
+      ["git", "diff", "--no-index", "--color=always", "--", "before.ts", "after.ts"],
       {
         cwd: dir,
         stdin: "ignore",

src/core/loaders.ts

@@ -19,6 +19,7 @@ import {
   runGitText,
   runGitUntrackedFileDiffText,
 } from "./git";
+import { runDifftasticStructural } from "./structural-diff";
 import type {
   AppBootstrap,
   AgentContext,
@@ -39,7 +40,7 @@ interface LoadAppBootstrapOptions {
 
 /** Return the final path segment for display-oriented labels. */
 function basename(path: string) {
-  return path.split("/").filter(Boolean).pop() ?? path;
+  return path.split(/[\\/]/).filter(Boolean).pop() ?? path;
 }
 
 /** Remove git-style a/ and b/ prefixes before matching diff paths. */
@@ -139,6 +140,7 @@ interface BuildDiffFileOptions {
   isUntracked?: boolean;
   previousPath?: string;
   isBinary?: boolean;
+  structuralChanges?: DiffFile["structuralChanges"];
 }
 
 /** Build the normalized per-file model used by the UI regardless of input mode. */
@@ -148,7 +150,7 @@ function buildDiffFile(
   index: number,
   sourcePrefix: string,
   agentContext: AgentContext | null,
-  { isUntracked, previousPath, isBinary }: BuildDiffFileOptions = {},
+  { isUntracked, previousPath, isBinary, structuralChanges }: BuildDiffFileOptions = {},
 ): DiffFile {
   const normalizedMetadata = normalizeDiffMetadataPaths(metadata);
   const path = normalizedMetadata.name;
@@ -165,6 +167,7 @@ function buildDiffFile(
     agent: findAgentFileContext(agentContext, path, resolvedPreviousPath),
     isUntracked,
     isBinary: isBinary ?? patchLooksBinary(patch),
+    structuralChanges,
   };
 }
 
@@ -432,6 +435,9 @@ async function loadFileDiffChangeset(
   const patch = createTwoFilesPatch(displayPath, displayPath, leftText, rightText, "", "", {
     context: 3,
   });
+  const structuralChanges = input.options.structural
+    ? runDifftasticStructural(leftText, rightText, displayPath)
+    : undefined;
 
   return {
     id: `pair:${displayPath}`,
@@ -441,6 +447,7 @@ async function loadFileDiffChangeset(
     files: [
       buildDiffFile(metadata, patch, 0, displayPath, agentContext, {
         previousPath: basename(input.left),
+        structuralChanges,
       }),
     ],
   } satisfies Changeset;