feat(vcs): add adapter abstraction

src/core/config.test.ts

@@ -161,7 +161,7 @@ describe("config resolution", () => {
     expect(fallbackResolved.input.options.excludeUntracked).toBe(false);
   });
 
-  test("defaults to git VCS mode and accepts jj from config", () => {
+  test("defaults to git VCS mode and accepts registered VCS modes from config", () => {
     const home = createTempDir("hunk-config-home-");
     mkdirSync(join(home, ".config", "hunk"), { recursive: true });
     writeFileSync(join(home, ".config", "hunk", "config.toml"), 'vcs = "jj"\n');
@@ -188,7 +188,7 @@ describe("config resolution", () => {
     expect(configuredResolved.input.options.vcs).toBe("jj");
   });
 
-  test("auto-detects jj checkouts before falling back to git mode", () => {
+  test("auto-detects registered VCS checkouts before falling back to git mode", () => {
     const home = createTempDir("hunk-config-home-");
     const jjRepo = createTempDir("hunk-config-jj-repo-");
     const colocatedRepo = createTempDir("hunk-config-colocated-repo-");

src/core/config.ts

@@ -1,6 +1,7 @@
 import fs from "node:fs";
-import { dirname, join, resolve } from "node:path";
+import { join } from "node:path";
 import { resolveGlobalConfigPath } from "./paths";
+import { detectVcs, findVcsRepoRootCandidate, isVcsId } from "./vcs";
 import type {
   CliInput,
   CommonOptions,
@@ -39,7 +40,7 @@ function normalizeLayoutMode(value: unknown): LayoutMode | undefined {
 
 /** Accept only the VCS backends Hunk can load directly. */
 function normalizeVcsMode(value: unknown): VcsMode | undefined {
-  return value === "git" || value === "jj" ? value : undefined;
+  return isVcsId(value) ? value : undefined;
 }
 
 /** Accept only plain booleans from config files. */
@@ -101,31 +102,9 @@ function resolveConfigLayer(source: Record<string, unknown>, input: CliInput): C
   return resolved;
 }
 
-/** Return the first parent that looks like a repository root. */
-function findRepoRoot(cwd = process.cwd()) {
-  let current = resolve(cwd);
-
-  for (;;) {
-    if (fs.existsSync(join(current, ".git")) || fs.existsSync(join(current, ".jj"))) {
-      return current;
-    }
-
-    const parent = dirname(current);
-    if (parent === current) {
-      return undefined;
-    }
-
-    current = parent;
-  }
-}
-
 /** Choose the VCS backend that best matches the discovered checkout. */
-function detectRepoVcsMode(repoRoot?: string): VcsMode {
-  if (repoRoot && fs.existsSync(join(repoRoot, ".jj"))) {
-    return "jj";
-  }
-
-  return "git";
+function detectRepoVcsMode(cwd: string): VcsMode {
+  return detectVcs(cwd)?.id ?? "git";
 }
 
 /** Parse one TOML config file into a plain object. */
@@ -147,13 +126,13 @@ export function resolveConfiguredCliInput(
   input: CliInput,
   { cwd = process.cwd(), env = process.env }: ConfigResolutionOptions = {},
 ): HunkConfigResolution {
-  const repoRoot = findRepoRoot(cwd);
+  const repoRoot = findVcsRepoRootCandidate(cwd);
   const repoConfigPath = repoRoot ? join(repoRoot, ".hunk", "config.toml") : undefined;
   const userConfigPath = resolveGlobalConfigPath(env);
 
   let resolvedOptions: CommonOptions = {
     mode: DEFAULT_VIEW_PREFERENCES.mode,
-    vcs: detectRepoVcsMode(repoRoot),
+    vcs: detectRepoVcsMode(cwd),
     // Keep the built-in theme default explicit so stdin-backed startup paths do not depend on
     // renderer theme-mode detection for their initial palette.
     theme: "graphite",

src/core/jj.test.ts

@@ -5,6 +5,8 @@ import { join } from "node:path";
 import { buildJjDiffArgs, runJjText } from "./jj";
 
 const tempDirs: string[] = [];
+// Windows subprocess setup can exceed Bun's default 5s timeout while generating enough jj changes.
+const JjAmbiguousPrefixTestTimeoutMs = 20_000;
 
 function cleanupTempDirs() {
   while (tempDirs.length > 0) {
@@ -131,36 +133,40 @@ describe("jj command helpers", () => {
     ).toThrow("`hunk diff missing_revision` could not resolve Jujutsu revset `missing_revision`.");
   });
 
-  test("reports a friendly error for ambiguous change id prefixes", () => {
-    const dir = createTempJjRepo("hunk-jj-ambiguous-prefix-");
-    let prefix: string | undefined;
-
-    for (let index = 0; index < 32 && !prefix; index += 1) {
-      writeFileSync(join(dir, `file-${index}.txt`), `${index}\n`);
-      jj(dir, "commit", "-m", `commit ${index}`);
-
-      prefix = findDuplicatePrefix(
-        jj(dir, "log", "--no-graph", "-T", 'change_id ++ "\n"').trim().split("\n"),
-      );
-    }
-
-    if (!prefix) {
-      throw new Error("Expected generated jj changes to include an ambiguous prefix.");
-    }
-
-    const input = {
-      kind: "vcs" as const,
-      range: prefix,
-      staged: false,
-      options: { mode: "auto" as const, vcs: "jj" as const },
-    };
-
-    expect(() =>
-      runJjText({
-        input,
-        args: buildJjDiffArgs(input),
-        cwd: dir,
-      }),
-    ).toThrow(`\`hunk diff ${prefix}\` could not resolve Jujutsu revset \`${prefix}\`.`);
-  });
+  test(
+    "reports a friendly error for ambiguous change id prefixes",
+    () => {
+      const dir = createTempJjRepo("hunk-jj-ambiguous-prefix-");
+      let prefix: string | undefined;
+
+      for (let index = 0; index < 32 && !prefix; index += 1) {
+        writeFileSync(join(dir, `file-${index}.txt`), `${index}\n`);
+        jj(dir, "commit", "-m", `commit ${index}`);
+
+        prefix = findDuplicatePrefix(
+          jj(dir, "log", "--no-graph", "-T", 'change_id ++ "\n"').trim().split("\n"),
+        );
+      }
+
+      if (!prefix) {
+        throw new Error("Expected generated jj changes to include an ambiguous prefix.");
+      }
+
+      const input = {
+        kind: "vcs" as const,
+        range: prefix,
+        staged: false,
+        options: { mode: "auto" as const, vcs: "jj" as const },
+      };
+
+      expect(() =>
+        runJjText({
+          input,
+          args: buildJjDiffArgs(input),
+          cwd: dir,
+        }),
+      ).toThrow(`\`hunk diff ${prefix}\` could not resolve Jujutsu revset \`${prefix}\`.`);
+    },
+    JjAmbiguousPrefixTestTimeoutMs,
+  );
 });