fix(project): prevent cross-repo project_id cache collisions for bare repos

packages/opencode/src/project/project.ts

@@ -119,17 +119,25 @@ export namespace Project {
           }
         }
 
-        const worktree = await git(["rev-parse", "--git-common-dir"], {
+        const common = await git(["rev-parse", "--git-common-dir"], {
           cwd: sandbox,
         })
           .then(async (result) => {
-            const common = gitpath(sandbox, await result.text())
+            const resolved = gitpath(sandbox, await result.text())
             // Avoid going to parent of sandbox when git-common-dir is empty.
-            return common === sandbox ? sandbox : path.dirname(common)
+            return resolved === sandbox ? sandbox : resolved
           })
           .catch(() => undefined)
 
-        if (!worktree) {
+        // worktree is the repo root: parent of .git for normal repos,
+        // but for bare repos (e.g. opencode.git) path.dirname gives
+        // the parent directory which may be shared across repos.
+        // If common resolves to sandbox (empty git-common-dir output),
+        // preserve sandbox to keep previous fallback behavior.
+        // Only used for the returned project info, not for cache paths.
+        const worktree = common ? (common === sandbox ? sandbox : path.dirname(common)) : undefined
+
+        if (!worktree || !common) {
           return {
             id: id ?? ProjectID.global,
             worktree: sandbox,
@@ -140,9 +148,11 @@ export namespace Project {
 
         // In the case of a git worktree, it can't cache the id
         // because `.git` is not a folder, but it always needs the
-        // same project id as the common dir, so we resolve it now
+        // same project id as the common dir, so we resolve it now.
+        // Use `common` directly (the git dir) instead of reconstructing
+        // worktree + "/.git" which breaks for bare repos (e.g. repo.git).
         if (id == null) {
-          id = await readCachedId(path.join(worktree, ".git"))
+          id = await readCachedId(common)
         }
 
         // generate id from root commit
@@ -170,8 +180,10 @@ export namespace Project {
 
           id = roots[0] ? ProjectID.make(roots[0]) : undefined
           if (id) {
-            // Write to common dir so the cache is shared across worktrees.
-            await Filesystem.write(path.join(worktree, ".git", "opencode"), id).catch(() => undefined)
+            // Write cache inside the git common dir itself, not worktree/.git.
+            // For bare repos (e.g. opencode.git), worktree/.git would resolve
+            // to the parent org directory's .git, corrupting other repos.
+            await Filesystem.write(path.join(common, "opencode"), id).catch(() => undefined)
           }
         }
 

packages/opencode/test/project/project.test.ts

@@ -218,6 +218,28 @@ describe("Project.fromDirectory with worktrees", () => {
     }
   })
 
+  test("different bare repos under same parent should not share project ID", async () => {
+    const p = await loadProject()
+    await using parent = await tmpdir()
+    await using repoA = await tmpdir({ git: true })
+    await using repoB = await tmpdir({ git: true })
+
+    const bareA = path.join(parent.path, "repo-a.git")
+    const bareB = path.join(parent.path, "repo-b.git")
+    const wtA = path.join(parent.path, "wt-a")
+    const wtB = path.join(parent.path, "wt-b")
+
+    await $`git clone --bare ${repoA.path} ${bareA}`.quiet()
+    await $`git clone --bare ${repoB.path} ${bareB}`.quiet()
+    await $`git --git-dir=${bareA} worktree add ${wtA} -b wt-a-${Date.now()} HEAD`.quiet()
+    await $`git --git-dir=${bareB} worktree add ${wtB} -b wt-b-${Date.now()} HEAD`.quiet()
+
+    const { project: a } = await p.fromDirectory(wtA)
+    const { project: b } = await p.fromDirectory(wtB)
+
+    expect(a.id).not.toBe(b.id)
+  })
+
   test("should accumulate multiple worktrees in sandboxes", async () => {
     const p = await loadProject()
     await using tmp = await tmpdir({ git: true })