From ea9e23bf4691dfe912c1ff58344321821b581610 Mon Sep 17 00:00:00 2001
From: Matthew Hawkins <darthmdh@gmail.com>
Date: Fri, 19 May 2017 11:11:25 +1000
Subject: [PATCH] Preference Python 3

Make Python 3 the preferred option, and ensure pip is correctly invoked on systems like Debian that support coexistent python installations.
Assume on other systems that we either win with Python 3 by default, or we were going to lose in any case and just fall back to python 2.
---
 upgrade.sh | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/upgrade.sh b/upgrade.sh
index 53e0c1db6..e2b94b253 100755
--- a/upgrade.sh
+++ b/upgrade.sh
@@ -20,9 +20,17 @@ COMMAND="${PREFIX}find . -name \"*.pyc\" -delete"
 echo "Cleaning up stale Python bytecode ($COMMAND)..."
 eval $COMMAND
 
-# Fall back to pip3 if pip is missing
-PIP="pip"
-type $PIP >/dev/null 2>&1 || PIP="pip3"
+# Prefer Python 3
+PIP=pip
+if type -P pip3 >/dev/null 2>&1; then
+	# We're likely on something Debian-based with numbered coexistent pythons.
+	# If we're running 3.4 or better, use pip3 and invoke scripts with python3
+	pip_version=$(pip3 --version | sed -e 's/.*(python \(.*\))/\1/')
+	if [[ ${pip_version:0:1} == 3 && ${pip_version:2:1} -gt 3 ]]; then
+		PIP=pip3
+		find . -type f -name '*.py' -execdir sed -i -e '1s/python/python3/' {} +
+	fi
+fi
 
 # Install any new Python packages
 COMMAND="${PREFIX}${PIP} install -r requirements.txt --upgrade"