From 85cd2f075e57aef46f265ea1af2da67729af3748 Mon Sep 17 00:00:00 2001
From: Darren Kavanagh <dkav@users.noreply.github.com>
Date: Wed, 8 May 2024 13:53:10 -0700
Subject: [PATCH] cmd/update.sh: check initial branch is not master

Check that the initial branch is not 'master' before doing a forced update on 'master'. Git will fail with fatal error otherwise.
---
 Library/Homebrew/cmd/update.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/cmd/update.sh b/Library/Homebrew/cmd/update.sh
index b3806891df..4a6ad15dfd 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -266,7 +266,8 @@ EOS
     then
       git checkout --force "${UPSTREAM_BRANCH}" "${QUIET_ARGS[@]}"
     else
-      if [[ -n "${UPSTREAM_TAG}" && "${UPSTREAM_BRANCH}" != "master" ]]
+      if [[ -n "${UPSTREAM_TAG}" && "${UPSTREAM_BRANCH}" != "master" ]] &&
+         [[ "${INITIAL_BRANCH}" != "master" ]]
       then
         git branch --force "master" "origin/master" "${QUIET_ARGS[@]}"
       fi