refactor: extract bundled Git provider

.changeset/large-showers-heal.md

@@ -0,0 +1,2 @@
+---
+---

.dependency-cruiser.cjs

@@ -71,6 +71,17 @@ module.exports = {
       from: { path: "^packages/hunk-vcs/src/" },
       to: { path: "^packages/", pathNot: "^packages/hunk-vcs/src/" },
     },
+    {
+      name: "hunk-git-stays-on-vcs-contract",
+      comment:
+        "@hunk/git owns the Git provider and may reach only its local modules, the public extension contract, and explicit dependency-bottom @hunk/vcs leaves.",
+      severity: "error",
+      from: { path: "^packages/hunk-git/src/" },
+      to: {
+        path: "^packages/",
+        pathNot: "^packages/(hunk-git|hunk-vcs)/src/|^packages/hunk/src/extension-api/",
+      },
+    },
     {
       name: "lib-is-a-leaf",
       comment:
@@ -177,9 +188,12 @@ module.exports = {
     {
       name: "packages-stay-standalone",
       comment:
-        "Workspace packages are standalone publishable units; they never import the app source tree.",
+        "Workspace packages are standalone units; bundled providers are governed by their narrower public-contract rules above, while other packages never import the app source tree.",
       severity: "error",
-      from: { path: "^packages/(?!hunk/)" },
+      from: {
+        path: "^packages/(?!hunk/)",
+        pathNot: "^packages/hunk-git/",
+      },
       to: { path: "^packages/hunk/src/" },
     },
   ],

knip.json

@@ -38,6 +38,10 @@
       "project": ["src/**/*.{ts,tsx}", "bin/**/*.cjs"],
       "ignoreExportsUsedInFile": true
     },
+    "packages/hunk-git": {
+      "entry": ["src/**/*.test.ts"],
+      "project": ["src/**/*.ts"]
+    },
     "packages/hunk-vcs": {
       "entry": ["src/**/*.test.ts"],
       "project": ["src/**/*.ts"]

nix/bun.lock.nix

@@ -53,6 +53,7 @@
     url = "https://registry.npmjs.org/@hono/node-ws/-/node-ws-1.3.1.tgz";
     hash = "sha512-vo/MwCnpJAVHBkGzWjCJ28wF45fYHAfbPZcH2rodZODHtch2GHA94KtMfusmVycTUtsLAsaNsHhtY6P8X3RQsA==";
   };
+  "@hunk/git" = copyPathToStore ../packages/hunk-git;
   "@hunk/session-broker" = copyPathToStore ../packages/session-broker;
   "@hunk/session-broker-bun" = copyPathToStore ../packages/session-broker-bun;
   "@hunk/session-broker-core" = copyPathToStore ../packages/session-broker-core;

package.json

@@ -77,6 +77,7 @@
   },
   "devDependencies": {
     "@changesets/changelog-github": "^0.7.0",
+    "@hunk/git": "workspace:*",
     "@hunk/session-broker": "workspace:*",
     "@hunk/session-broker-bun": "workspace:*",
     "@hunk/session-broker-core": "workspace:*",

packages/hunk-git/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@hunk/git",
+  "version": "0.0.0",
+  "private": true,
+  "description": "Private statically bundled Git provider for Hunk.",
+  "license": "MIT",
+  "files": [
+    "src"
+  ],
+  "type": "module",
+  "sideEffects": false,
+  "exports": {
+    ".": {
+      "types": "./src/index.ts",
+      "import": "./src/index.ts"
+    }
+  },
+  "dependencies": {
+    "@hunk/vcs": "workspace:*",
+    "hunkdiff": "workspace:*"
+  },
+  "engines": {
+    "bun": ">=1.3.14",
+    "node": ">=22"
+  }
+}

packages/hunk/src/extensions/default/vcs/git/commands.ts → packages/hunk-git/src/commands.ts

@@ -14,9 +14,8 @@ import { runAbortableCommand } from "@hunk/vcs/async-process";
 /**
  * Every Git command Hunk runs, and the failures they translate into.
  *
- * This is the implementation layer behind the bundled Git backend
- * (`packages/hunk/src/extensions/default/vcs/git/`), so nothing here reaches into core, the
- * diff engine, or the adapter registry — user-facing failures are raised as the
+ * This is the implementation layer behind the bundled Git backend. Nothing here
+ * reaches into core, the diff engine, or the adapter registry — user-facing failures are raised as the
  * published `HunkExtensionUserError`, which is exactly what a third-party
  * backend would throw.
  */
@@ -51,7 +50,7 @@ export interface GitColorMovedOptions {
 }
 
 /** Append Git pathspec arguments only when the caller requested them. */
-export function appendGitPathspecs(args: string[], pathspecs?: string[]) {
+function appendGitPathspecs(args: string[], pathspecs?: string[]) {
   if (!pathspecs || pathspecs.length === 0) {
     return;
   }
@@ -65,7 +64,7 @@ export function appendGitPathspecs(args: string[], pathspecs?: string[]) {
  * example `--output=<path>`) that Git would parse as a flag; it fails closed here instead
  * of reaching the spawned command.
  */
-export function requireGitRevisionArg(input: GitBackedInput, value: string) {
+function requireGitRevisionArg(input: GitBackedInput, value: string) {
   if (value.length === 0) {
     throw new HunkExtensionUserError(
       `\`${formatGitCommandLabel(input)}\` refused an empty revision.`,
@@ -306,7 +305,7 @@ export function buildGitStashShowArgs(
   return withNormalizedDiffPrefixes(withGitMovedLineColorConfig(args, colorMoved));
 }
 
-export function formatGitCommandLabel(input: GitBackedInput) {
+function formatGitCommandLabel(input: GitBackedInput) {
   switch (input.kind) {
     case "vcs": {
       if (input.staged) {
@@ -869,7 +868,7 @@ export function resolveGitRepoRoot(
 }
 
 /** Resolve one commit-ish ref to the exact commit object used for later blob reads. */
-export function resolveGitCommitRef(
+function resolveGitCommitRef(
   input: GitBackedInput,
   ref: string,
   options: Omit<RunGitTextOptions, "input" | "args"> = {},

packages/hunk/src/core/changeset/loaders.test.ts

@@ -13,7 +13,7 @@ import { join } from "node:path";
 import { replaceExtensionFileLanguages } from "./fileLanguage";
 import { SourceTextTooLargeError } from "./fileSource";
 import { getBundledVcsCatalog } from "../../app/vcsCatalog";
-import { createGitVcsAdapter } from "../../extensions/default/vcs/git";
+import { createGitVcsAdapter } from "@hunk/git";
 import { toInternalVcsAdapter } from "../../extensions/runExtension";
 import { createVcsCatalog } from "../vcs";
 import { loadAppBootstrap as loadCoreAppBootstrap, type LoadAppBootstrapOptions } from "./loaders";

packages/hunk/src/extensions/default/vcs/index.ts

@@ -1,4 +1,4 @@
-import gitExtension from "./git";
+import gitExtension from "@hunk/git";
 import jjExtension from "./jujutsu";
 import slExtension from "./sapling";
 import { runExtensionFactory } from "../../runExtension";

scripts/hunk-git-package.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, test } from "bun:test";
+import gitExtension, { GitVcsAdapter } from "@hunk/git";
+import { readFileSync } from "node:fs";
+import { join, resolve } from "node:path";
+
+const REPO_ROOT = resolve(import.meta.dir, "..");
+const PACKAGE_ROOT = join(REPO_ROOT, "packages", "hunk-git");
+
+describe("@hunk/git package boundary", () => {
+  test("exports only the explicit Git provider entry", () => {
+    const manifest = JSON.parse(readFileSync(join(PACKAGE_ROOT, "package.json"), "utf8")) as {
+      name: string;
+      private: boolean;
+      files: string[];
+      exports: Record<string, unknown>;
+      dependencies: Record<string, string>;
+    };
+
+    expect(manifest.name).toBe("@hunk/git");
+    expect(manifest.private).toBe(true);
+    expect(manifest.files).toEqual(["src"]);
+    expect(manifest.exports).toEqual({
+      ".": {
+        types: "./src/index.ts",
+        import: "./src/index.ts",
+      },
+    });
+    expect(manifest.dependencies).toEqual({
+      "@hunk/vcs": "workspace:*",
+      hunkdiff: "workspace:*",
+    });
+  });
+
+  test("registers the private workspace without leaking it into hunkdiff", () => {
+    const rootManifest = JSON.parse(readFileSync(join(REPO_ROOT, "package.json"), "utf8")) as {
+      devDependencies: Record<string, string>;
+    };
+    const hunkManifest = readFileSync(join(REPO_ROOT, "packages", "hunk", "package.json"), "utf8");
+    const bunLock = readFileSync(join(REPO_ROOT, "bun.lock"), "utf8");
+    const nixLock = readFileSync(join(REPO_ROOT, "nix", "bun.lock.nix"), "utf8");
+
+    expect(rootManifest.devDependencies["@hunk/git"]).toBe("workspace:*");
+    expect(hunkManifest).not.toContain("@hunk/git");
+    expect(hunkManifest).not.toContain("workspace:");
+    expect(bunLock).toContain('"packages/hunk-git": {');
+    expect(bunLock).toContain('"@hunk/git@workspace:packages/hunk-git"');
+    expect(nixLock).toContain('"@hunk/git" = copyPathToStore ../packages/hunk-git;');
+  });
+
+  test("loads its provider entrypoint through the workspace", () => {
+    expect(typeof gitExtension).toBe("function");
+    expect(GitVcsAdapter.id).toBe("git");
+  });
+});

scripts/source-boundaries.test.ts

@@ -7,6 +7,7 @@ const SRC_ROOT = join(REPO_ROOT, "packages", "hunk", "src");
 const CORE_ROOT = join(SRC_ROOT, "core");
 const EXTENSIONS_ROOT = join(SRC_ROOT, "extensions");
 const BUNDLED_PROVIDER_ROOT = join(EXTENSIONS_ROOT, "default", "vcs");
+const GIT_PACKAGE_ROOT = join(REPO_ROOT, "packages", "hunk-git", "src");
 const VCS_PACKAGE_ROOT = join(REPO_ROOT, "packages", "hunk-vcs", "src");
 const REVIEW_MODEL_ROOT = join(CORE_ROOT, "review");
 // The published extension contract, which the review model may name for the annotation shapes
@@ -166,18 +167,25 @@ function unexpectedProviderImports() {
     "@hunk/vcs/path",
     "@hunk/vcs/source",
   ]);
-  return sourceFiles(BUNDLED_PROVIDER_ROOT).flatMap((path) =>
-    importSpecifiers(path)
-      // The repository-wide lightweight scanner can also match prose ending in `from "…"`;
-      // real module specifiers never contain whitespace.
-      .filter((specifier) => !/\s/.test(specifier))
-      .filter(
-        (specifier) =>
-          !specifier.startsWith(".") &&
-          !specifier.startsWith("node:") &&
-          !allowedImports.has(specifier),
-      )
-      .map((specifier) => `${repoPath(path)} -> ${specifier}`),
+  return [BUNDLED_PROVIDER_ROOT, GIT_PACKAGE_ROOT].flatMap((providerRoot) =>
+    sourceFiles(providerRoot).flatMap((path) =>
+      importSpecifiers(path)
+        // The lightweight scanner can match prose ending in `from "…"`; module specifiers
+        // never contain whitespace.
+        .filter((specifier) => !/\s/.test(specifier))
+        .filter((specifier) => {
+          if (
+            specifier.startsWith(".") ||
+            specifier.startsWith("node:") ||
+            specifier.startsWith("bun:") ||
+            allowedImports.has(specifier)
+          ) {
+            return false;
+          }
+          return !(path === join(BUNDLED_PROVIDER_ROOT, "index.ts") && specifier === "@hunk/git");
+        })
+        .map((specifier) => `${repoPath(path)} -> ${specifier}`),
+    ),
   );
 }
 
@@ -303,6 +311,7 @@ describe("source architecture boundaries", () => {
 
   test("keeps bundled providers on the public contract and explicit VCS helper leaves", () => {
     expect(forbiddenImports(BUNDLED_PROVIDER_ROOT, CORE_ROOT)).toEqual([]);
+    expect(escapingImports(GIT_PACKAGE_ROOT, [GIT_PACKAGE_ROOT])).toEqual([]);
     expect(unexpectedProviderImports()).toEqual([]);
   });
 

tsconfig.json

@@ -14,6 +14,7 @@
     "types": ["bun", "react"],
     "baseUrl": ".",
     "paths": {
+      "@hunk/git": ["packages/hunk-git/src/index.ts"],
       "@hunk/session-broker": ["packages/session-broker/src/index.ts"],
       "@hunk/session-broker-bun": ["packages/session-broker-bun/src/index.ts"],
       "@hunk/session-broker-core": ["packages/session-broker-core/src/index.ts"],