various Python 3.9 changes

mmgen/cfg.py

@@ -75,10 +75,7 @@ class GlobalConstants(Lockable):
 		#        Resource Access without the performance overhead of that package.
 		#    https://importlib-resources.readthedocs.io/en/latest/migration.html
 		#    https://setuptools.readthedocs.io/en/latest/pkg_resources.html
-		try:
-			from importlib.resources import files # Python 3.9
-		except ImportError:
-			from importlib_resources import files
+		from importlib.resources import files
 		return files(package).joinpath('data',filename).read_text()
 
 	@property

mmgen/proto/btc/tw/addresses.py

@@ -50,7 +50,7 @@ Actions: [q]uit menu, r[e]draw, add [l]abel:
 		msg('done')
 
 		amt0 = self.proto.coin_amt('0')
-		self.total = sum((v['amt'] for v in addrs.values())) or amt0 # Python 3.8: start=amt0
+		self.total = sum((v['amt'] for v in addrs.values()), start=amt0)
 
 		msg_r('Getting labels and associated addresses...')
 		pairs = await self.get_addr_label_pairs()

mmgen/proto/eth/tw/json.py

@@ -92,7 +92,7 @@ class EthereumTwJSON(TwJSON):
 			def gen_data(data):
 				for d in data:
 					if hasattr(d,'address'):
-						if d.amount is None: # Python 3.9: {} | {}
+						if d.amount is None:
 							yield (d.address, {'mmid':d.mmgen_id,'comment':TwComment(d.comment)})
 						else:
 							yield (d.address, {'mmid':d.mmgen_id,'comment':TwComment(d.comment),'balance':d.amount})

mmgen/rpc.py

@@ -247,9 +247,8 @@ class RPCBackends:
 
 			from subprocess import run,PIPE
 			from .color import set_vt100
-			res = run(exec_cmd,stdout=PIPE,check=True).stdout.decode()
+			res = run(exec_cmd,stdout=PIPE,check=True,text=True).stdout
 			set_vt100()
-			# res = run(exec_cmd,stdout=PIPE,check=True,text='UTF-8').stdout # Python 3.7+
 			return (res[:-3],int(res[-3:]))
 
 class RPCClient(MMGenObject):

mmgen/util2.py

@@ -30,12 +30,6 @@ def die_pause(ev=0,s=''):
 	input('Press ENTER to exit')
 	sys.exit(ev)
 
-def removeprefix(s,pfx): # workaround for pre-Python 3.9
-	return s[len(pfx):] if s.startswith(pfx) else s
-
-def removesuffix(s,sfx): # workaround for pre-Python 3.9
-	return s[:-len(sfx)] if s.endswith(sfx) else s
-
 # monkey-patch function for monero-python: permits its use with pycryptodome (e.g. MSYS2)
 # instead of the expected pycryptodomex
 def load_cryptodomex():

scripts/exec_wrapper.py

@@ -51,12 +51,8 @@ def exec_wrapper_write_traceback(e,exit_val):
 		overlay_path_pfx = os.path.relpath(get_overlay_tree_dir(cwd)) + '/'
 
 		def fixup_fn(fn_in):
-			from mmgen.util2 import removeprefix,removesuffix
-			fn = removeprefix(removeprefix(fn_in,cwd+'/'),overlay_path_pfx)
-			return removesuffix(fn,'_orig.py') + '.py' if fn.endswith('_orig.py') else fn
-			# Python 3.9:
-			# fn = fn_in.removeprefix(cwd+'/').removeprefix('test/overlay/tree/')
-			# return fn.removesuffix('_orig.py') + '.py' if fn.endswith('_orig.py') else fn
+			fn = fn_in.removeprefix(cwd+'/').removeprefix(overlay_path_pfx)
+			return fn.removesuffix('_orig.py') + '.py' if fn.endswith('_orig.py') else fn
 
 		def gen_output():
 			yield 'Traceback (most recent call last):'

setup.cfg

@@ -39,7 +39,6 @@ python_requires = >=3.9
 include_package_data = True
 
 install_requires =
-	importlib-resources; python_version < "3.9"
 	gmpy2
 	cryptography
 	pynacl

test/cmdtest.py

@@ -406,9 +406,7 @@ class CmdGroupMgr:
 		def gen():
 			for name,data in cls.cmd_group_in:
 				if name.startswith('subgroup.'):
-					from mmgen.util2 import removeprefix
-					sg_key = removeprefix(name,'subgroup.')
-#					sg_key = name.removeprefix('subgroup.') # Python 3.9
+					sg_key = name.removeprefix('subgroup.')
 					if sg_name in (None,sg_key):
 						for e in add_entries(
 								sg_key,

test/overlay/__init__.py

@@ -31,12 +31,11 @@ def overlay_setup(repo_root):
 				d == f'{pkgname}.data' or
 				(d == 'mmgen.proto.secp256k1' and fn.startswith('secp256k1'))
 			):
-				if os.path.exists(os.path.join(fakemod_dir,fn)):
+				if fn.endswith('.py') and os.path.exists(os.path.join(fakemod_dir,fn)):
 					make_link(
 						os.path.join(fakemod_dir,fn),
 						os.path.join(destdir,fn) )
-#					link_fn = fn.removesuffix('.py') + '_orig.py' # Python 3.9
-					link_fn = fn[:-3] + '_orig.py'
+					link_fn = fn.removesuffix('.py') + '_orig.py'
 				else:
 					link_fn = fn
 				make_link(
@@ -47,7 +46,7 @@ def overlay_setup(repo_root):
 	fakemod_root = os.path.join(repo_root,'test','overlay','fakemods')
 	common_path = os.path.join(os.path.sep,'test','overlay','fakemods')
 	pkgdata = ((
-			os.path.realpath(e.path)[:-len(os.path.join(common_path,e.name))], # Python 3.9: removesuffix()
+			os.path.realpath(e.path).removesuffix(os.path.join(common_path,e.name)),
 			e.name
 		) for e in os.scandir(fakemod_root) if e.is_dir() )