From 34ae75d511b2ff696ece406826eb2b0aff01ce6b Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Mon, 11 Jun 2018 20:10:40 +0100
Subject: [PATCH] brew.sh: enable linkage cache for developers.

This seems stable on CI so I think we can expose it to more people.
---
 Library/Homebrew/brew.sh          | 5 +++++
 Library/Homebrew/dev-cmd/tests.rb | 1 -
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index ba7572439b..984571de1f 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -277,6 +277,11 @@ then
   HOMEBREW_BASH_COMMAND="$HOMEBREW_LIBRARY/Homebrew/dev-cmd/$HOMEBREW_COMMAND.sh"
 fi
 
+if [[ -n "$HOMEBREW_DEVELOPER" || -n "$HOMEBREW_DEV_CMD_RUN" ]]
+then
+  export HOMEBREW_LINKAGE_CACHE="1"
+fi
+
 check-run-command-as-root() {
   [[ "$(id -u)" = 0 ]] || return
 
diff --git a/Library/Homebrew/dev-cmd/tests.rb b/Library/Homebrew/dev-cmd/tests.rb
index d462e2bee2..fba2bac1c1 100644
--- a/Library/Homebrew/dev-cmd/tests.rb
+++ b/Library/Homebrew/dev-cmd/tests.rb
@@ -38,7 +38,6 @@ module Homebrew
       ENV.delete("VERBOSE")
       ENV.delete("HOMEBREW_CASK_OPTS")
       ENV.delete("HOMEBREW_TEMP")
-      ENV.delete("HOMEBREW_LINKAGE_CACHE")
       ENV.delete("HOMEBREW_NO_GITHUB_API")
       ENV.delete("HOMEBREW_NO_EMOJI")
       ENV["HOMEBREW_NO_ANALYTICS_THIS_RUN"] = "1"