Merge bitcoin#10781: Python cleanups

7821458 Use for-loop instead of list comprehension (practicalswift)
8239794 Use the variable name _ for unused return values (practicalswift)
2e6080b Remove unused variables and/or function calls (practicalswift)
9b94054 Avoid reference to undefined name: stderr does not exist, sys.stderr does (practicalswift)
51cb6b8 Use print(...) instead of undefined printf(...) (practicalswift)
25cd520 Use sys.exit(...) instead of exit(...): exit(...) should not be used in programs (practicalswift)

Pull request description:

  Python cleanups:
  * Avoid reference to undefined name: `stderr` does not exist, `sys.stderr` does
  * Use `print(...)` instead of undefined `printf(...)`
  * Avoid redefinition of variable (`tx`) in list comprehension
  * Remove unused variables and/or function calls
  * Use `sys.exit(...)` instead of `exit(...)`: [`exit(...)` should not be used in programs](bitcoin#10753 (comment))

Tree-SHA512: 1238dfbc1d20f7edadea5e5406a589f293065638f6234809f0d5b6ba746dffe3d276bc5884c7af388a6c798c61a8759faaccf57f381225644754c0f61914eb4b

contrib/devtools/check-doc.py

@@ -12,6 +12,7 @@
 
 from subprocess import check_output
 import re
+import sys
 
 FOLDER_GREP = 'src'
 FOLDER_TEST = 'src/test/'
@@ -39,7 +40,7 @@ def main():
   print("Args unknown     : {}".format(len(args_unknown)))
   print(args_unknown)
 
-  exit(len(args_need_doc))
+  sys.exit(len(args_need_doc))
 
 if __name__ == "__main__":
     main()

contrib/devtools/github-merge.py

@@ -20,6 +20,7 @@
 import argparse
 import hashlib
 import subprocess
+import sys
 import json,codecs
 try:
     from urllib.request import Request,urlopen
@@ -158,11 +159,11 @@ def main():
     if repo is None:
         print("ERROR: No repository configured. Use this command to set:", file=stderr)
         print("git config githubmerge.repository <owner>/<repo>", file=stderr)
-        exit(1)
+        sys.exit(1)
     if signingkey is None:
         print("ERROR: No GPG signing key set. Set one using:",file=stderr)
         print("git config --global user.signingkey <key>",file=stderr)
-        exit(1)
+        sys.exit(1)
 
     host_repo = host+":"+repo # shortcut for push/pull target
 
@@ -173,7 +174,7 @@ def main():
     # Receive pull information from github
     info = retrieve_pr_info(repo,pull)
     if info is None:
-        exit(1)
+        sys.exit(1)
     title = info['title'].strip()
     body = info['body'].strip()
     # precedence order for destination branch argument:
@@ -194,27 +195,27 @@ def main():
         subprocess.check_call([GIT,'checkout','-q',branch])
     except subprocess.CalledProcessError as e:
         print("ERROR: Cannot check out branch %s." % (branch), file=stderr)
-        exit(3)
+        sys.exit(3)
     try:
         subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/pull/'+pull+'/*:refs/heads/pull/'+pull+'/*'])
     except subprocess.CalledProcessError as e:
         print("ERROR: Cannot find pull request #%s on %s." % (pull,host_repo), file=stderr)
-        exit(3)
+        sys.exit(3)
     try:
         subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+head_branch], stdout=devnull, stderr=stdout)
     except subprocess.CalledProcessError as e:
         print("ERROR: Cannot find head of pull request #%s on %s." % (pull,host_repo), file=stderr)
-        exit(3)
+        sys.exit(3)
     try:
         subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+merge_branch], stdout=devnull, stderr=stdout)
     except subprocess.CalledProcessError as e:
         print("ERROR: Cannot find merge of pull request #%s on %s." % (pull,host_repo), file=stderr)
-        exit(3)
+        sys.exit(3)
     try:
         subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/heads/'+branch+':refs/heads/'+base_branch])
     except subprocess.CalledProcessError as e:
         print("ERROR: Cannot find branch %s on %s." % (branch,host_repo), file=stderr)
-        exit(3)
+        sys.exit(3)
     subprocess.check_call([GIT,'checkout','-q',base_branch])
     subprocess.call([GIT,'branch','-q','-D',local_merge_branch], stderr=devnull)
     subprocess.check_call([GIT,'checkout','-q','-b',local_merge_branch])
@@ -236,30 +237,30 @@ def main():
         except subprocess.CalledProcessError as e:
             print("ERROR: Cannot be merged cleanly.",file=stderr)
             subprocess.check_call([GIT,'merge','--abort'])
-            exit(4)
+            sys.exit(4)
         logmsg = subprocess.check_output([GIT,'log','--pretty=format:%s','-n','1']).decode('utf-8')
         if logmsg.rstrip() != firstline.rstrip():
             print("ERROR: Creating merge failed (already merged?).",file=stderr)
-            exit(4)
+            sys.exit(4)
 
         symlink_files = get_symlink_files()
         for f in symlink_files:
             print("ERROR: File %s was a symlink" % f)
         if len(symlink_files) > 0:
-            exit(4)
+            sys.exit(4)
 
         # Put tree SHA512 into the message
         try:
             first_sha512 = tree_sha512sum()
             message += '\n\nTree-SHA512: ' + first_sha512
         except subprocess.CalledProcessError as e:
-            printf("ERROR: Unable to compute tree hash")
-            exit(4)
+            print("ERROR: Unable to compute tree hash")
+            sys.exit(4)
         try:
             subprocess.check_call([GIT,'commit','--amend','-m',message.encode('utf-8')])
         except subprocess.CalledProcessError as e:
-            printf("ERROR: Cannot update message.",file=stderr)
-            exit(4)
+            print("ERROR: Cannot update message.", file=stderr)
+            sys.exit(4)
 
         print_merge_details(pull, title, branch, base_branch, head_branch)
         print()
@@ -268,7 +269,7 @@ def main():
         if testcmd:
             if subprocess.call(testcmd,shell=True):
                 print("ERROR: Running %s failed." % testcmd,file=stderr)
-                exit(5)
+                sys.exit(5)
 
             # Show the created merge.
             diff = subprocess.check_output([GIT,'diff',merge_branch+'..'+local_merge_branch])
@@ -279,7 +280,7 @@ def main():
                 if reply.lower() == 'ignore':
                     print("Difference with github ignored.",file=stderr)
                 else:
-                    exit(6)
+                    sys.exit(6)
         else:
             # Verify the result manually.
             print("Dropping you on a shell so you can try building/testing the merged source.",file=stderr)
@@ -292,7 +293,7 @@ def main():
         second_sha512 = tree_sha512sum()
         if first_sha512 != second_sha512:
             print("ERROR: Tree hash changed unexpectedly",file=stderr)
-            exit(8)
+            sys.exit(8)
 
         # Sign the merge commit.
         print_merge_details(pull, title, branch, base_branch, head_branch)
@@ -306,7 +307,7 @@ def main():
                     print("Error while signing, asking again.",file=stderr)
             elif reply == 'x':
                 print("Not signing off on merge, exiting.",file=stderr)
-                exit(1)
+                sys.exit(1)
 
         # Put the result in branch.
         subprocess.check_call([GIT,'checkout','-q',branch])
@@ -326,7 +327,7 @@ def main():
             subprocess.check_call([GIT,'push',host_repo,'refs/heads/'+branch])
             break
         elif reply == 'x':
-            exit(1)
+            sys.exit(1)
 
 if __name__ == '__main__':
     main()

contrib/devtools/security-check.py

@@ -211,5 +211,5 @@ def identify_executable(executable):
         except IOError:
             print('%s: cannot open' % filename)
             retval = 1
-    exit(retval)
+    sys.exit(retval)
 

contrib/devtools/symbol-check.py

@@ -158,6 +158,6 @@ def read_libraries(filename):
                 print('%s: NEEDED library %s is not allowed' % (filename, library_name))
                 retval = 1
 
-    exit(retval)
+    sys.exit(retval)
 
 

contrib/devtools/update-translations.py

@@ -35,12 +35,12 @@ def check_at_repository_root():
     if not os.path.exists('.git'):
         print('No .git directory found')
         print('Execute this script at the root of the repository', file=sys.stderr)
-        exit(1)
+        sys.exit(1)
 
 def fetch_all_translations():
     if subprocess.call([TX, 'pull', '-f', '-a']):
         print('Error while fetching translations', file=sys.stderr)
-        exit(1)
+        sys.exit(1)
 
 def find_format_specifiers(s):
     '''Find all format specifiers in a string.'''

contrib/linearize/linearize-hashes.py

@@ -87,7 +87,7 @@ def get_block_hashes(settings, max_blocks_per_call=10000):
 		for x,resp_obj in enumerate(reply):
 			if rpc.response_is_error(resp_obj):
 				print('JSON-RPC: error at height', height+x, ': ', resp_obj['error'], file=sys.stderr)
-				exit(1)
+				sys.exit(1)
 			assert(resp_obj['id'] == x) # assume replies are in-sequence
 			if settings['rev_hash_bytes'] == 'true':
 				resp_obj['result'] = hex_switchEndian(resp_obj['result'])
@@ -140,7 +140,7 @@ def get_rpc_cookie():
 	if 'datadir' in settings and not use_userpass:
 		use_datadir = True
 	if not use_userpass and not use_datadir:
-		print("Missing datadir or username and/or password in cfg file", file=stderr)
+		print("Missing datadir or username and/or password in cfg file", file=sys.stderr)
 		sys.exit(1)
 
 	settings['port'] = int(settings['port'])

contrib/seeds/generate-seeds.py

@@ -114,7 +114,7 @@ def process_nodes(g, f, structname, defaultport):
 def main():
     if len(sys.argv)<2:
         print(('Usage: %s <path_to_nodes_txt>' % sys.argv[0]), file=sys.stderr)
-        exit(1)
+        sys.exit(1)
     g = sys.stdout
     indir = sys.argv[1]
     g.write('#ifndef DASH_CHAINPARAMSSEEDS_H\n')

contrib/zmq/zmq_sub.py

@@ -32,7 +32,7 @@
 
 if not (sys.version_info.major >= 3 and sys.version_info.minor >= 5):
     print("This example only works with Python 3.5 and greater")
-    exit(1)
+    sys.exit(1)
 
 port = 28332
 

contrib/zmq/zmq_sub3.4.py

@@ -36,7 +36,7 @@
 
 if not (sys.version_info.major >= 3 and sys.version_info.minor >= 4):
     print("This example only works with Python 3.4 and greater")
-    exit(1)
+    sys.exit(1)
 
 port = 28332
 

share/qt/extract_strings_qt.py

@@ -57,7 +57,7 @@ def parse_po(text):
 if not XGETTEXT:
     print('Cannot extract strings: xgettext utility is not installed or not configured.',file=sys.stderr)
     print('Please install package "gettext" and re-run \'./configure\'.',file=sys.stderr)
-    exit(1)
+    sys.exit(1)
 child = Popen([XGETTEXT,'--output=-','-n','--keyword=_'] + files, stdout=PIPE)
 (out, err) = child.communicate()
 

test/functional/bip68-sequence.py

@@ -388,7 +388,7 @@ def test_version2_relay(self):
         tx = FromHex(CTransaction(), rawtxfund)
         tx.nVersion = 2
         tx_signed = self.nodes[1].signrawtransaction(ToHex(tx))["hex"]
-        tx_id = self.nodes[1].sendrawtransaction(tx_signed)
+        self.nodes[1].sendrawtransaction(tx_signed)
 
 if __name__ == '__main__':
     BIP68Test().main()

test/functional/fundrawtransaction.py

@@ -310,7 +310,6 @@ def run_test(self):
         ##############################################
         # test a fundrawtransaction with invalid vin #
         ##############################################
-        listunspent = self.nodes[2].listunspent()
         inputs  = [ {'txid' : "1c7f966dab21119bac53213a2bc7532bff1fa844c124fd750a7d0b1332440bd1", 'vout' : 0} ] #invalid vin!
         outputs = { self.nodes[0].getnewaddress() : 10}
         rawtx   = self.nodes[2].createrawtransaction(inputs, outputs)

test/functional/import-rescan.py

@@ -167,7 +167,6 @@ def run_test(self):
                 variant.check()
 
         # Create new transactions sending to each address.
-        fee = self.nodes[0].getnetworkinfo()["relayfee"]
         for i, variant in enumerate(IMPORT_VARIANTS):
             variant.sent_amount = 10 - (2 * i + 1) / 8.0
             variant.sent_txid = self.nodes[0].sendtoaddress(variant.address["address"], variant.sent_amount)

test/functional/importmulti.py

@@ -20,16 +20,7 @@ def run_test (self):
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
 
-        # keyword definition
-        PRIV_KEY = 'privkey'
-        PUB_KEY = 'pubkey'
-        ADDRESS_KEY = 'address'
-        SCRIPT_KEY = 'script'
-
-
         node0_address1 = self.nodes[0].validateaddress(self.nodes[0].getnewaddress())
-        node0_address2 = self.nodes[0].validateaddress(self.nodes[0].getnewaddress())
-        node0_address3 = self.nodes[0].validateaddress(self.nodes[0].getnewaddress())
 
         #Check only one address
         assert_equal(node0_address1['ismine'], True)
@@ -241,7 +232,6 @@ def run_test (self):
         transactionid = self.nodes[1].sendtoaddress(multi_sig_script['address'], 10.00)
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
-        transaction = self.nodes[1].gettransaction(transactionid)
 
         self.log.info("Should import a p2sh")
         result = self.nodes[1].importmulti([{
@@ -269,7 +259,6 @@ def run_test (self):
         transactionid = self.nodes[1].sendtoaddress(multi_sig_script['address'], 10.00)
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
-        transaction = self.nodes[1].gettransaction(transactionid)
 
         self.log.info("Should import a p2sh with respective redeem script")
         result = self.nodes[1].importmulti([{
@@ -297,7 +286,6 @@ def run_test (self):
         transactionid = self.nodes[1].sendtoaddress(multi_sig_script['address'], 10.00)
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
-        transaction = self.nodes[1].gettransaction(transactionid)
 
         self.log.info("Should import a p2sh with respective redeem script and private keys")
         result = self.nodes[1].importmulti([{
@@ -325,7 +313,6 @@ def run_test (self):
         transactionid = self.nodes[1].sendtoaddress(multi_sig_script['address'], 10.00)
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
-        transaction = self.nodes[1].gettransaction(transactionid)
 
         self.log.info("Should import a p2sh with respective redeem script and private keys")
         result = self.nodes[1].importmulti([{

test/functional/importprunedfunds.py

@@ -21,7 +21,6 @@ def run_test(self):
         address1 = self.nodes[0].getnewaddress()
         # pubkey
         address2 = self.nodes[0].getnewaddress()
-        address2_pubkey = self.nodes[0].validateaddress(address2)['pubkey']                 # Using pubkey
         # privkey
         address3 = self.nodes[0].getnewaddress()
         address3_privkey = self.nodes[0].dumpprivkey(address3)                              # Using privkey
@@ -74,13 +73,13 @@ def run_test(self):
 
         #Import with affiliated address with no rescan
         self.nodes[1].importaddress(address2, "add2", False)
-        result2 = self.nodes[1].importprunedfunds(rawtxn2, proof2)
+        self.nodes[1].importprunedfunds(rawtxn2, proof2)
         balance2 = self.nodes[1].getbalance("add2", 0, False, True)
         assert_equal(balance2, Decimal('0.05'))
 
         #Import with private key with no rescan
         self.nodes[1].importprivkey(privkey=address3_privkey, label="add3", rescan=False)
-        result3 = self.nodes[1].importprunedfunds(rawtxn3, proof3)
+        self.nodes[1].importprunedfunds(rawtxn3, proof3)
         balance3 = self.nodes[1].getbalance("add3", 0, False, False)
         assert_equal(balance3, Decimal('0.025'))
         balance3 = self.nodes[1].getbalance("*", 0, False, True)

test/functional/mempool_packages.py

@@ -211,7 +211,7 @@ def run_test(self):
         value = send_value
 
         # Create tx1
-        (tx1_id, tx1_value) = self.chain_transaction(self.nodes[0], tx0_id, 0, value, fee, 1)
+        tx1_id, _ = self.chain_transaction(self.nodes[0], tx0_id, 0, value, fee, 1)
 
         # Create tx2-7
         vout = 1

test/functional/p2p-compactblocks.py

@@ -258,7 +258,8 @@ def test_compactblock_construction(self, node, test_node, version):
 
         # Store the raw block in our internal format.
         block = FromHex(CBlock(), node.getblock("%02x" % block_hash, False))
-        [tx.calc_sha256() for tx in block.vtx]
+        for tx in block.vtx:
+            tx.calc_sha256()
         block.rehash()
 
         # Wait until the block was announced (via compact blocks)