fix: pass HF token via git credential helper instead of embedding in remote URLs

worker.py

@@ -215,11 +215,15 @@ def copy_repo_with_history(src: str, dst: str, repo_type: str) -> int:
     objects. The destination repo must already exist (pre-created by the
     calling Space).
 
-    Auth: the canonical HF pattern (matches what `hf auth login
-    --add-to-git-credential` writes) is HTTP Basic auth with username
-    `hf_user` and the access token as the password. We embed those in the
-    clone/push URLs. The token leaks into the temp `.git/config` only —
-    we delete the whole directory at the end.
+    Auth: the canonical HF pattern is HTTP Basic with username `hf_user` and
+    the access token as the password. Rather than embedding the token in the
+    clone/push URLs (which exposes it in the process command line, the temp
+    `.git/config`, and any git output echoed into the Job logs), we register a
+    git credential helper that reads the token from `HF_TOKEN` in the
+    environment at request time. The token therefore never appears on a command
+    line or in a config file; only the helper script (which references
+    `$HF_TOKEN`) is stored. The Job container is single-tenant and ephemeral,
+    so a global credential helper is safe here.
     """
     if repo_type not in REPO_TYPE_URL_PREFIX:
         log(f"unsupported type: {repo_type}")
@@ -232,11 +236,22 @@ def copy_repo_with_history(src: str, dst: str, repo_type: str) -> int:
 
     prefix = REPO_TYPE_URL_PREFIX[repo_type]
     base = HF_ENDPOINT.replace("https://", "")
-    src_url = f"https://hf_user:{token}@{base}/{prefix}{src}"
-    dst_url = f"https://hf_user:{token}@{base}/{prefix}{dst}"
+    src_url = f"https://{base}/{prefix}{src}"
+    dst_url = f"https://{base}/{prefix}{dst}"
     src_label = f"{prefix}{src}"
     dst_label = f"{prefix}{dst}"
 
+    # Authenticate via a credential helper that reads HF_TOKEN from the env at
+    # request time, so the token never lands in a remote URL, the process
+    # command line, or .git/config. Applies to ls-remote, fetch, lfs and push.
+    _run([
+        "git",
+        "config",
+        "--global",
+        "credential.helper",
+        '!f() { echo "username=hf_user"; echo "password=${HF_TOKEN}"; }; f',
+    ])
+
     _ensure_git_lfs()
     xet_available = _ensure_git_xet_binary()