gnu: diffoscope: Update to 166.

* gnu/packages/diffoscope.scm (diffoscope): Update to 166.
  [source]: Add patch to use magic.open compatibility interface.
* gnu/packages/patches/diffoscope-revert-to-magic-open.patch: New file.
* gnu/local.mk [dist_patch_DATA]: New patch.

gnu/local.mk

@@ -926,6 +926,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/desmume-gcc6-fixes.patch			\
   %D%/packages/patches/desmume-gcc7-fixes.patch			\
   %D%/packages/patches/dfu-programmer-fix-libusb.patch		\
+  %D%/packages/patches/diffoscope-revert-to-magic-open.patch	\
   %D%/packages/patches/diffutils-gets-undeclared.patch		\
   %D%/packages/patches/dkimproxy-add-ipv6-support.patch		\
   %D%/packages/patches/docbook-xsl-nonrecursive-string-subst.patch	\

gnu/packages/diffoscope.scm

@@ -72,7 +72,7 @@
 (define-public diffoscope
   (package
     (name "diffoscope")
-    (version "165")
+    (version "166")
     (source (origin
               (method git-fetch)
               (uri (git-reference
@@ -81,7 +81,9 @@
               (file-name (git-file-name name version))
               (sha256
                (base32
-                "0chi8drkxdwk7mlfgljij0nihnxp9pi5ybhqaq8rc4l1zl6srirb"))))
+                "0vc4a38ii6b10af4c7cxfkvj4lk4ihx1xs4q5lshnkyg74gmm21b"))
+              (patches (search-patches
+                        "diffoscope-revert-to-magic-open.patch"))))
     (build-system python-build-system)
     (arguments
      `(#:phases (modify-phases %standard-phases

gnu/packages/patches/diffoscope-revert-to-magic-open.patch

@@ -0,0 +1,70 @@
+From b658c3a6819ccb9a104b13e973132c66f0965965 Mon Sep 17 00:00:00 2001
+From: Vagrant Cascadian <vagrant@reproducible-builds.org>
+Date: Thu, 11 Feb 2021 17:28:21 -0800
+Subject: [PATCH] Revert "Prefer to use magic.Magic over the magic.open
+ compatibility interface. (Closes: reproducible-builds/diffoscope#236)"
+
+This reverts commit c72c30f29ea3760eb4c785644dc7cd4c26833740.
+---
+ diffoscope/comparators/utils/file.py | 28 ++++++++++++++--------------
+ 1 file changed, 14 insertions(+), 14 deletions(-)
+
+diff --git a/diffoscope/comparators/utils/file.py b/diffoscope/comparators/utils/file.py
+index fb3b4316..32700f02 100644
+--- a/diffoscope/comparators/utils/file.py
++++ b/diffoscope/comparators/utils/file.py
+@@ -65,37 +65,37 @@ def _run_tests(fold, tests):
+ 
+ 
+ class File(metaclass=abc.ABCMeta):
+-    if hasattr(magic, "Magic"):  # use python-magic
++    if hasattr(magic, "open"):  # use Magic-file-extensions from file
+ 
+         @classmethod
+         def guess_file_type(cls, path):
+             if not hasattr(cls, "_mimedb"):
+-                cls._mimedb = magic.Magic()
+-            return maybe_decode(cls._mimedb.from_file(path))
++                cls._mimedb = magic.open(magic.NONE)
++                cls._mimedb.load()
++            return cls._mimedb.file(
++                path.encode("utf-8", errors="surrogateescape")
++            )
+ 
+         @classmethod
+         def guess_encoding(cls, path):
+             if not hasattr(cls, "_mimedb_encoding"):
+-                cls._mimedb_encoding = magic.Magic(mime_encoding=True)
+-            return maybe_decode(cls._mimedb_encoding.from_file(path))
++                cls._mimedb_encoding = magic.open(magic.MAGIC_MIME_ENCODING)
++                cls._mimedb_encoding.load()
++            return cls._mimedb_encoding.file(path)
+ 
+-    else:  # use Magic-file-extensions from file
++    else:  # use python-magic
+ 
+         @classmethod
+         def guess_file_type(cls, path):
+             if not hasattr(cls, "_mimedb"):
+-                cls._mimedb = magic.open(magic.NONE)
+-                cls._mimedb.load()
+-            return cls._mimedb.file(
+-                path.encode("utf-8", errors="surrogateescape")
+-            )
++                cls._mimedb = magic.Magic()
++            return maybe_decode(cls._mimedb.from_file(path))
+ 
+         @classmethod
+         def guess_encoding(cls, path):
+             if not hasattr(cls, "_mimedb_encoding"):
+-                cls._mimedb_encoding = magic.open(magic.MAGIC_MIME_ENCODING)
+-                cls._mimedb_encoding.load()
+-            return cls._mimedb_encoding.file(path)
++                cls._mimedb_encoding = magic.Magic(mime_encoding=True)
++            return maybe_decode(cls._mimedb_encoding.from_file(path))
+ 
+     def __init__(self, container=None):
+         self._comments = []
+-- 
+2.30.0
+