fix(pwd): find origin from inside a linked git worktree

src/pwd.mjs

@@ -19,6 +19,20 @@ function resolveGitDir(dotgit, dir) {
   return null;
 }
 
+// A linked worktree's git dir (.git/worktrees/<name>) holds only that
+// worktree's own HEAD and index — the shared config, and therefore the
+// remotes, stay in the main repo's git dir. Git names it in a `commondir`
+// file, usually as a path relative to the worktree's git dir. Resolve it so
+// origin is found from inside a worktree; outside one there is no such file
+// and the git dir is already the common one.
+function commonGitDir(gitDir) {
+  try {
+    const pointer = fs.readFileSync(path.join(gitDir, "commondir"), "utf8").trim();
+    if (pointer) return path.resolve(gitDir, pointer);
+  } catch { /* not a linked worktree */ }
+  return gitDir;
+}
+
 // Walk up from `start` until we find a `.git` with a readable HEAD (a real
 // repo). A bare `.git` dir with no HEAD — e.g. a stray /tmp/.git — is skipped,
 // not mistaken for a repo. Returns { root, gitDir } or null at the fs root.
@@ -74,8 +88,9 @@ export function locate(cwd = process.cwd()) {
     git: {
       root: found.root,
       name: path.basename(found.root),
+      // HEAD is per-worktree; config (and its remotes) is shared.
       branch: readBranch(found.gitDir),
-      origin: readOrigin(found.gitDir),
+      origin: readOrigin(commonGitDir(found.gitDir)),
     },
   };
 }

test/pwd.test.mjs

@@ -1,8 +1,10 @@
 import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
 import path from "node:path";
 import test from "node:test";
 
-import { tilde } from "../src/pwd.mjs";
+import { locate, tilde } from "../src/pwd.mjs";
 
 test("tilde shortens the home directory itself", () => {
   const home = path.join("C:", "Users", "mosh");
@@ -23,3 +25,51 @@ test("tilde does not shorten sibling paths with the same prefix", () => {
 
   assert.equal(tilde(sibling, home), sibling);
 });
+
+// Build a main repo plus one linked worktree the way git lays them out on disk,
+// without needing git on PATH: the worktree's `.git` is a file pointing at
+// .git/worktrees/<name>, which carries its own HEAD and a `commondir` back to
+// the main git dir that holds the shared config.
+function fakeWorktree(root, { commondir }) {
+  const mainGit = path.join(root, "main", ".git");
+  const linkedGit = path.join(mainGit, "worktrees", "feature");
+  fs.mkdirSync(linkedGit, { recursive: true });
+  fs.writeFileSync(path.join(mainGit, "HEAD"), "ref: refs/heads/main\n");
+  fs.writeFileSync(
+    path.join(mainGit, "config"),
+    '[core]\n\tbare = false\n[remote "origin"]\n\turl = https://github.com/moshcoder/moshcode.git\n\tfetch = +refs/heads/*:refs/remotes/origin/*\n',
+  );
+  fs.writeFileSync(path.join(linkedGit, "HEAD"), "ref: refs/heads/feature\n");
+  fs.writeFileSync(path.join(linkedGit, "commondir"), `${commondir}\n`);
+
+  const worktree = path.join(root, "feature");
+  fs.mkdirSync(worktree, { recursive: true });
+  fs.writeFileSync(path.join(worktree, ".git"), `gitdir: ${linkedGit}\n`);
+  return worktree;
+}
+
+test("locate reports origin from inside a linked worktree", () => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "moshcode-worktree-"));
+  try {
+    // git writes commondir relative to the worktree's own git dir.
+    const worktree = fakeWorktree(root, { commondir: path.join("..", "..") });
+    const { git } = locate(worktree);
+
+    assert.equal(git.branch, "feature");
+    assert.equal(git.origin, "https://github.com/moshcoder/moshcode.git");
+  } finally {
+    fs.rmSync(root, { recursive: true, force: true });
+  }
+});
+
+test("locate follows an absolute commondir too", () => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "moshcode-worktree-"));
+  try {
+    const worktree = fakeWorktree(root, { commondir: path.join(root, "main", ".git") });
+    const { git } = locate(worktree);
+
+    assert.equal(git.origin, "https://github.com/moshcoder/moshcode.git");
+  } finally {
+    fs.rmSync(root, { recursive: true, force: true });
+  }
+});