[gentoo-portage-dev] [PATCH 08/14] portage.checksum: Remove exception handling for missing hashlib

[Michał Górny]

Remove the try-except block for potential ImportError of hashlib.
The hashlib module should be available in all supported Python versions,
and we do not really test or support the case when it is not available.
---
 pym/portage/checksum.py | 55 ++++++++++++++++++++++---------------------------
 1 file changed, 25 insertions(+), 30 deletions(-)

diff --git a/pym/portage/checksum.py b/pym/portage/checksum.py
index 7812791ad..68ed44fa9 100644
--- a/pym/portage/checksum.py
+++ b/pym/portage/checksum.py
@@ -9,6 +9,8 @@ from portage import os
 from portage import _encodings
 from portage import _unicode_decode, _unicode_encode
 import errno
+import functools
+import hashlib
 import stat
 import sys
 import subprocess
@@ -99,7 +101,7 @@ class _generate_hash_function(object):
 # pycrypto. However, it might be the only accelerated implementation of
 # WHIRLPOOL available.
 try:
-	import mhash, functools
+	import mhash
 	for local_name, hash_name in (("rmd160", "ripemd160"), ("whirlpool", "whirlpool")):
 		if hasattr(mhash, 'MHASH_%s' % local_name.upper()):
 			globals()['%shash' % local_name] = \
@@ -124,7 +126,6 @@ except ImportError:
 try:
 	# added in pycryptodome
 	from Crypto.Hash import BLAKE2b, BLAKE2s, SHA3_256, SHA3_512
-	import functools
 
 	blake2bhash_ = getattr(BLAKE2b, 'new', None)
 	if blake2bhash_ is not None:
@@ -156,34 +157,28 @@ except ImportError:
 
 # Use hashlib from python-2.5 if available and prefer it over pycrypto and internal fallbacks.
 # Need special handling for RMD160/WHIRLPOOL as they may not always be provided by hashlib.
-try:
-	import hashlib, functools
-	
-	md5hash = _generate_hash_function("MD5", hashlib.md5, origin="hashlib")
-	sha1hash = _generate_hash_function("SHA1", hashlib.sha1, origin="hashlib")
-	sha256hash = _generate_hash_function("SHA256", hashlib.sha256, origin="hashlib")
-	sha512hash = _generate_hash_function("SHA512", hashlib.sha512, origin="hashlib")
-	for local_name, hash_name in (
-			("rmd160", "ripemd160"),
-			("whirlpool", "whirlpool"),
-			# available since Python 3.6
-			("BLAKE2B", "blake2b"),
-			("BLAKE2S", "blake2s"),
-			("SHA3_256", "sha3_256"),
-			("SHA3_512", "sha3_512"),
-			):
-		try:
-			hashlib.new(hash_name)
-		except ValueError:
-			pass
-		else:
-			globals()['%shash' % local_name] = \
-				_generate_hash_function(local_name.upper(), \
-				functools.partial(hashlib.new, hash_name), \
-				origin='hashlib')
-
-except ImportError:
-	pass
+md5hash = _generate_hash_function("MD5", hashlib.md5, origin="hashlib")
+sha1hash = _generate_hash_function("SHA1", hashlib.sha1, origin="hashlib")
+sha256hash = _generate_hash_function("SHA256", hashlib.sha256, origin="hashlib")
+sha512hash = _generate_hash_function("SHA512", hashlib.sha512, origin="hashlib")
+for local_name, hash_name in (
+		("rmd160", "ripemd160"),
+		("whirlpool", "whirlpool"),
+		# available since Python 3.6
+		("BLAKE2B", "blake2b"),
+		("BLAKE2S", "blake2s"),
+		("SHA3_256", "sha3_256"),
+		("SHA3_512", "sha3_512"),
+		):
+	try:
+		hashlib.new(hash_name)
+	except ValueError:
+		pass
+	else:
+		globals()['%shash' % local_name] = \
+			_generate_hash_function(local_name.upper(), \
+			functools.partial(hashlib.new, hash_name), \
+			origin='hashlib')
 
 _whirlpool_unaccelerated = False
 if "WHIRLPOOL" not in hashfunc_map:
-- 
2.12.0