From 129ee966f8a9d1287d3407f81b214ba744b7d4c5 Mon Sep 17 00:00:00 2001
From: Misty De Meo <mistydemeo@gmail.com>
Date: Thu, 11 May 2017 12:06:55 -0700
Subject: [PATCH 1/3] Optionally use Python's flock instead of Ruby's

Ruby first gained flock in 1.8.7, which is a problem since we're using
this lock utility in `vendor-install` in order to install a newer Ruby.

Fortunately, Python 2.3(!) has flock support.
---
 Library/Homebrew/utils/lock.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/utils/lock.sh b/Library/Homebrew/utils/lock.sh
index 7f0638c1ac..04d8fd1d59 100644
--- a/Library/Homebrew/utils/lock.sh
+++ b/Library/Homebrew/utils/lock.sh
@@ -38,14 +38,19 @@ _create_lock() {
   local lock_fd="$1"
   local name="$2"
   local ruby="/usr/bin/ruby"
+  local python="/usr/bin/python"
   [[ -x "$ruby" ]] || ruby="$(which ruby 2>/dev/null)"
+  [[ -x "$python" ]] || python="$(which python 2>/dev/null)"
 
-  if [[ -n "$ruby" ]]
+  if [[ -n "$ruby" && $("$ruby" -e "puts RUBY_VERSION >= '1.8.7' ? 0 : 1") = 0 ]]
   then
     "$ruby" -e "File.new($lock_fd).flock(File::LOCK_EX | File::LOCK_NB) || exit(1)"
   elif [[ -n "$(which flock)" ]]
   then
     flock -n "$lock_fd"
+  elif [[ -n "$python" ]]
+  then
+    "$python" -c "import fcntl; fcntl.flock($lock_fd, fcntl.LOCK_EX | fcntl.LOCK_NB)"
   else
     onoe "Cannot create $name lock, please avoid running Homebrew in parallel."
   fi

From 94ed3e358399db37ff88c8a53c6c8cbf7a44e51e Mon Sep 17 00:00:00 2001
From: Misty De Meo <mistydemeo@gmail.com>
Date: Tue, 23 May 2017 18:36:06 -0700
Subject: [PATCH 2/3] lock: check tools are executable

---
 Library/Homebrew/utils/lock.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Library/Homebrew/utils/lock.sh b/Library/Homebrew/utils/lock.sh
index 04d8fd1d59..b3c23c3ef3 100644
--- a/Library/Homebrew/utils/lock.sh
+++ b/Library/Homebrew/utils/lock.sh
@@ -42,13 +42,13 @@ _create_lock() {
   [[ -x "$ruby" ]] || ruby="$(which ruby 2>/dev/null)"
   [[ -x "$python" ]] || python="$(which python 2>/dev/null)"
 
-  if [[ -n "$ruby" && $("$ruby" -e "puts RUBY_VERSION >= '1.8.7' ? 0 : 1") = 0 ]]
+  if [[ -x "$ruby" && $("$ruby" -e "puts RUBY_VERSION >= '1.8.7' ? 0 : 1") = 0 ]]
   then
     "$ruby" -e "File.new($lock_fd).flock(File::LOCK_EX | File::LOCK_NB) || exit(1)"
-  elif [[ -n "$(which flock)" ]]
+  elif [[ -x "$(which flock)" ]]
   then
     flock -n "$lock_fd"
-  elif [[ -n "$python" ]]
+  elif [[ -x "$python" ]]
   then
     "$python" -c "import fcntl; fcntl.flock($lock_fd, fcntl.LOCK_EX | fcntl.LOCK_NB)"
   else

From 67dc3323ed1368ffc6a49899c8b98732dc2eb181 Mon Sep 17 00:00:00 2001
From: Misty De Meo <mistydemeo@gmail.com>
Date: Wed, 24 May 2017 09:12:21 -0700
Subject: [PATCH 3/3] lock: simplify ruby conditional

---
 Library/Homebrew/utils/lock.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Library/Homebrew/utils/lock.sh b/Library/Homebrew/utils/lock.sh
index b3c23c3ef3..7f2bb8b73f 100644
--- a/Library/Homebrew/utils/lock.sh
+++ b/Library/Homebrew/utils/lock.sh
@@ -42,7 +42,7 @@ _create_lock() {
   [[ -x "$ruby" ]] || ruby="$(which ruby 2>/dev/null)"
   [[ -x "$python" ]] || python="$(which python 2>/dev/null)"
 
-  if [[ -x "$ruby" && $("$ruby" -e "puts RUBY_VERSION >= '1.8.7' ? 0 : 1") = 0 ]]
+  if [[ -x "$ruby" ]] && "$ruby" -e "exit(RUBY_VERSION >= '1.8.7')"
   then
     "$ruby" -e "File.new($lock_fd).flock(File::LOCK_EX | File::LOCK_NB) || exit(1)"
   elif [[ -x "$(which flock)" ]]