From 35138dd6ddb42376f9c4d541557454bcf672c659 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@yossarian.net>
Date: Sat, 30 Jun 2018 09:34:21 -0400
Subject: [PATCH] brew.sh: Don't allow system tmp dirs as prefixes

---
 Library/Homebrew/brew.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index ba7572439b..b0a79d4cc3 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -294,6 +294,20 @@ EOS
 }
 check-run-command-as-root
 
+check-prefix-is-not-tmpdir() {
+  if [[ "${HOMEBREW_PREFIX}" = /tmp/* ||
+        "${HOMEBREW_PREFIX}" = /private/tmp/* ]]
+  then
+    odie <<EOS
+Your HOMEBREW_PREFIX is in one of the system temporary directories, which Homebrew
+uses to store downloads and builds. You can resolve this by installing Homebrew to
+either the standard prefix (/usr/local/) or to a non-standard prefix that is not
+a system temporary directory.
+EOS
+  fi
+}
+check-prefix-is-not-tmpdir
+
 if [[ "$HOMEBREW_PREFIX" = "/usr/local" &&
       "$HOMEBREW_PREFIX" != "$HOMEBREW_REPOSITORY" &&
       "$HOMEBREW_CELLAR" = "$HOMEBREW_REPOSITORY/Cellar" ]]