From 07866f0b54e0d8cd26f761922f242aa0ec73c40c Mon Sep 17 00:00:00 2001
From: Zhiming Wang <zmwangx@gmail.com>
Date: Sat, 24 Sep 2016 05:45:21 -0400
Subject: [PATCH] update.sh: do not restore stable (tag) branch

Restoring stable branch post-update could lead to unsuspecting users
with homebrew.devcmdrun being stuck forever on an old tag.

Fixes #1111.
---
 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 177958266c..ba230bdec2 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -297,7 +297,8 @@ EOS
 
   if [[ -n "$HOMEBREW_NO_UPDATE_CLEANUP" ]]
   then
-    if [[ "$INITIAL_BRANCH" != "$UPSTREAM_BRANCH" && -n "$INITIAL_BRANCH" ]]
+    if [[ "$INITIAL_BRANCH" != "$UPSTREAM_BRANCH" && -n "$INITIAL_BRANCH" &&
+          ! "$INITIAL_BRANCH" =~ ^v[0-9]+\.[0-9]+\.[0-9]$ ]]
     then
       git checkout "$INITIAL_BRANCH" "${QUIET_ARGS[@]}"
     fi