diffoscope 42 (new formula).

diffoscope will try to get to the bottom of what makes files or
directories different. It will recursively unpack archives of many
kinds and transform various binary formats into more human readable
form to compare them. It can compare two tarballs, ISO images, or PDF
just as easily.

Closes Homebrew/homebrew#46570.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Formula/diffoscope.rb

@@ -0,0 +1,49 @@
+class Diffoscope < Formula
+  desc "In-depth comparison of files, archives, and directories."
+  homepage "https://diffoscope.org"
+  url "https://pypi.python.org/packages/source/d/diffoscope/diffoscope-42.tar.gz"
+  sha256 "c0241acf5de7eb0e9e209e43dbf389beca722ddfb8b5d5630fd40569f1f465e2"
+
+  depends_on "libmagic"
+  depends_on "libarchive"
+  depends_on "gnu-tar"
+  depends_on :python3
+
+  resource "libarchive-c" do
+    url "https://pypi.python.org/packages/source/l/libarchive-c/libarchive-c-2.2.tar.gz"
+    sha256 "5d54aa6f6ab21e3bd12c2f8b6c4e80316b049c2b60ab0a4418cb34d8c63e997c"
+  end
+
+  resource "python-magic" do
+    url "https://pypi.python.org/packages/source/p/python-magic/python-magic-0.4.10.tar.gz"
+    sha256 "79fd2865ec96074749825f9e9562953995d5bf12b6793f24d75c37479ad4a2c3"
+  end
+
+  def install
+    # Submitted upstream to lunar@debian.org
+    inreplace "diffoscope/difference.py", "'diff', '-au7'", "'diff', '-aU7'"
+    inreplace "diffoscope/comparators/tar.py", "'tar'", "'gtar'"
+
+    pyver = Language::Python.major_minor_version "python3"
+    ENV.prepend_create_path "PYTHONPATH", libexec/"vendor/lib/python#{pyver}/site-packages"
+
+    resources.each do |r|
+      r.stage do
+        system "python3", *Language::Python.setup_install_args(libexec/"vendor")
+      end
+    end
+
+    ENV.prepend_create_path "PYTHONPATH", libexec/"lib/python#{pyver}/site-packages"
+    system "python3", *Language::Python.setup_install_args(libexec)
+    bin.install Dir[libexec/"bin/*"]
+    libarchive = Formula["libarchive"].opt_lib/"libarchive.dylib"
+    bin.env_script_all_files(libexec+"bin", :PYTHONPATH => ENV["PYTHONPATH"],
+                                            :LIBARCHIVE => libarchive)
+  end
+
+  test do
+    (testpath/"test1").write "test"
+    cp testpath/"test1", testpath/"test2"
+    system "#{bin}/diffoscope", "test1", "test2"
+  end
+end