fix(vcs): prefer nearest detected repository

CHANGELOG.md

@@ -12,6 +12,8 @@ All notable user-visible changes to Hunk are documented in this file.
 
 ### Fixed
 
+- Fixed VCS auto-detection so a Git repository nested under a parent Jujutsu workspace still uses Git mode by default.
+
 ## [0.13.1] - 2026-05-19
 
 ### Fixed

src/core/config.test.ts

@@ -246,12 +246,16 @@ describe("config resolution", () => {
     const jjRepo = createTempDir("hunk-config-jj-repo-");
     const colocatedRepo = createTempDir("hunk-config-colocated-repo-");
     const gitRepo = createTempDir("hunk-config-git-repo-");
+    const parentJjRepo = createTempDir("hunk-config-parent-jj-");
+    const gitRepoInsideParentJj = join(parentJjRepo, "git-project");
     const plainDir = createTempDir("hunk-config-no-repo-");
 
     createJjRepo(jjRepo);
     createRepo(colocatedRepo);
     createJjRepo(colocatedRepo);
     createRepo(gitRepo);
+    createJjRepo(parentJjRepo);
+    createRepo(gitRepoInsideParentJj);
 
     const input = {
       kind: "vcs",
@@ -269,6 +273,10 @@ describe("config resolution", () => {
     expect(
       resolveConfiguredCliInput(input, { cwd: gitRepo, env: { HOME: home } }).input.options.vcs,
     ).toBe("git");
+    expect(
+      resolveConfiguredCliInput(input, { cwd: gitRepoInsideParentJj, env: { HOME: home } }).input
+        .options.vcs,
+    ).toBe("git");
     expect(
       resolveConfiguredCliInput(input, { cwd: plainDir, env: { HOME: home } }).input.options.vcs,
     ).toBe("git");

src/core/vcs/index.test.ts

@@ -81,6 +81,18 @@ describe("VCS adapter registry", () => {
     expect(findVcsRepoRootCandidate(nested)).toBe(repo);
   });
 
+  test("prefers the nearest checkout over a parent repository with higher adapter priority", () => {
+    const parent = createTempDir("hunk-vcs-parent-jj-");
+    const repo = join(parent, "project");
+    const nested = join(repo, "src", "nested");
+    mkdirSync(join(parent, ".jj"));
+    mkdirSync(join(repo, ".git"), { recursive: true });
+    mkdirSync(nested, { recursive: true });
+
+    expect(detectVcs(nested)).toEqual({ id: "git", repoRoot: repo });
+    expect(findVcsRepoRootCandidate(nested)).toBe(repo);
+  });
+
   test("maps CLI inputs to neutral review operations", () => {
     const diffInput = {
       kind: "vcs",

src/core/vcs/index.ts

@@ -1,4 +1,4 @@
-import { dirname, resolve } from "node:path";
+import { dirname, relative, resolve } from "node:path";
 import { HunkUserError } from "../errors";
 import { gitAdapter } from "./git";
 import { jjAdapter } from "./jj";
@@ -18,14 +18,28 @@ export function isVcsId(value: unknown): value is VcsId {
   return vcsAdapters.some((adapter) => adapter.id === value);
 }
 
+/** Detect the nearest containing VCS checkout, using adapter order only to break same-root ties. */
 export function detectVcs(cwd: string): VcsDetection | null {
+  const start = resolve(cwd);
+  let bestDetection: VcsDetection | null = null;
+  let bestDistance = Number.POSITIVE_INFINITY;
+
   for (const adapter of vcsAdapters) {
-    const detected = adapter.detect(cwd);
-    if (detected) {
-      return detected;
+    const detected = adapter.detect(start);
+    if (!detected) {
+      continue;
+    }
+
+    const distance = relative(detected.repoRoot, start)
+      .split(/[\\/]+/)
+      .filter(Boolean).length;
+    if (distance < bestDistance) {
+      bestDetection = detected;
+      bestDistance = distance;
     }
   }
-  return null;
+
+  return bestDetection;
 }
 
 export function findVcsRepoRootCandidate(cwd = process.cwd()) {