From 19f941c3fc595289bc9d1bbcc35dfc43d2ad22e4 Mon Sep 17 00:00:00 2001
From: Josh Crites <jc@joshcrites.com>
Date: Mon, 2 Mar 2026 16:21:33 -0500
Subject: [PATCH] fix: disable gc.auto after blobless clones to prevent race
 condition

Blobless clones with sparsePathOverrides trigger on-demand blob fetches,
each of which runs `git gc --auto`. Concurrent gc processes collide with
"unable to write new index file" errors. Setting gc.auto=0 right after
clone prevents this. Safe for read-only clones used only for code search.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/utils/git.ts        | 3 +++
 tests/utils/git.test.ts | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/src/utils/git.ts b/src/utils/git.ts
index 7d10117..3cc7c13 100644
--- a/src/utils/git.ts
+++ b/src/utils/git.ts
@@ -76,6 +76,7 @@ export async function cloneRepo(
       ]);
 
       const repoGit = simpleGit(repoPath);
+      await repoGit.raw(["config", "gc.auto", "0"]);
       await repoGit.raw(["sparse-checkout", "set", ...config.sparse]);
       await repoGit.fetch(["origin", config.commit]);
       await repoGit.checkout(config.commit);
@@ -87,6 +88,7 @@ export async function cloneRepo(
       ]);
 
       const repoGit = simpleGit(repoPath);
+      await repoGit.raw(["config", "gc.auto", "0"]);
       await repoGit.raw(["sparse-checkout", "set", ...config.sparse]);
       await repoGit.fetch(["--depth=1", "origin", `refs/tags/${config.tag}:refs/tags/${config.tag}`]);
       await repoGit.checkout(config.tag);
@@ -117,6 +119,7 @@ export async function cloneRepo(
       ]);
 
       const repoGit = simpleGit(repoPath);
+      await repoGit.raw(["config", "gc.auto", "0"]);
       await repoGit.raw(["sparse-checkout", "set", ...config.sparse]);
     }
 
diff --git a/tests/utils/git.test.ts b/tests/utils/git.test.ts
index 8b79f89..4f5175f 100644
--- a/tests/utils/git.test.ts
+++ b/tests/utils/git.test.ts
@@ -132,6 +132,7 @@ describe("cloneRepo", () => {
       expect.stringContaining("aztec-packages"),
       expect.arrayContaining(["--filter=blob:none", "--sparse", "--no-checkout"])
     );
+    expect(mockGitInstance.raw).toHaveBeenCalledWith(["config", "gc.auto", "0"]);
     expect(mockGitInstance.raw).toHaveBeenCalledWith([
       "sparse-checkout",
       "set",
@@ -240,6 +241,7 @@ describe("cloneRepo", () => {
       expect.any(String),
       expect.arrayContaining(["--filter=blob:none", "--sparse", "--no-checkout"])
     );
+    expect(mockGitInstance.raw).toHaveBeenCalledWith(["config", "gc.auto", "0"]);
     expect(mockGitInstance.fetch).toHaveBeenCalledWith(["origin", "abc123def"]);
     expect(mockGitInstance.checkout).toHaveBeenCalledWith("abc123def");
   });
@@ -256,6 +258,7 @@ describe("cloneRepo", () => {
       expect.any(String),
       expect.arrayContaining(["--filter=blob:none", "--sparse", "--depth=1", "-b", "master"])
     );
+    expect(mockGitInstance.raw).toHaveBeenCalledWith(["config", "gc.auto", "0"]);
   });
 
   it("non-sparse + tag: clones without sparse-checkout", async () => {