Attempt to go Python3-only

Ubuntu 20.04 no longer really supports Python 2, so we'd have to fork
the packaging code if we wanted to keep support for Python 2
elsewhere.  Given that Python 3 has been around for a more than a
decade and that Python 2 was formally EOLed more than six months ago
as of this writing, this seems like an unnecessary complication.

The biggest change is rewriting the Homebrew formula for Python 3.

1 files changed, 9 insertions, 5 deletions

diff --git a/scripts/build-homebrew-formula.py b/scripts/build-homebrew-formula.py
index 54cdcae..852b4b6 100755
--- a/scripts/build-homebrew-formula.py
+++ b/scripts/build-homebrew-formula.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Yes, this is a Python program writing a Ruby program.
 
@@ -32,7 +32,7 @@ template = '''\
 # code, however, is what Homebrew considers "bindings", so we install
 # those where user scripts as well as our own can find them...then we
 # add a symlink so that our scripts can find our bindings regardless
-# of which copy of Python 2.7 Homebrew decides we should use this week.
+# of which copy of Python Homebrew decides we should use this week.
 #
 # We have to build our own software before installing our Python code,
 # because at least one of the Python modules we install
@@ -54,6 +54,8 @@ class {classname} < Formula
   url      "{url}"
   sha256   "{sha256}"
 
+  depends_on "python@3.8"
+
 {conflicts}
 
   resource "pyserial" do
@@ -88,11 +90,13 @@ class {classname} < Formula
 
   def install
 
-    ENV.prepend_create_path "PYTHONPATH", libexec/"vendor/lib/python2.7/site-packages"
+    xy = Language::Python.major_minor_version "python3"
+
+    ENV.prepend_create_path "PYTHONPATH", libexec/"vendor/lib/python#{xy}/site-packages"
 
     resources.each do |r|
       r.stage do
-        system "python", *Language::Python.setup_install_args(libexec/"vendor")
+        system "python3", *Language::Python.setup_install_args(libexec/"vendor")
       end
     end
 
@@ -103,7 +107,7 @@ class {classname} < Formula
     system "python", *Language::Python.setup_install_args(prefix)
     bin.env_script_all_files(libexec/"bin", :PYTHONPATH => ENV["PYTHONPATH"])
 
-    ln_s lib/"python2.7/site-packages/cryptech", libexec/"vendor/lib/python2.7/site-packages/cryptech"
+    ln_s lib/"python#{xy}/site-packages/cryptech", libexec/"vendor/lib/python#{xy}/site-packages/cryptech"
 
     share.install "cryptech-alpha-firmware.tar.gz"
     lib.install   "sw/pkcs11/libcryptech-pkcs11.dylib"