[Python-checkins] bpo-45975: Simplify some while-loops with walrus operator (GH-29347)
ethanfurman
webhook-mailer at python.org
Sat Nov 26 17:33:30 EST 2022
https://github.com/python/cpython/commit/024ac542d738f56b36bdeb3517a10e93da5acab9
commit: 024ac542d738f56b36bdeb3517a10e93da5acab9
branch: main
author: Nick Drozd <nicholasdrozd at gmail.com>
committer: ethanfurman <ethan at stoneleaf.us>
date: 2022-11-26T14:33:25-08:00
summary:
bpo-45975: Simplify some while-loops with walrus operator (GH-29347)
files:
M Lib/_pyio.py
M Lib/base64.py
M Lib/ctypes/_aix.py
M Lib/email/parser.py
M Lib/ftplib.py
M Lib/http/client.py
M Lib/http/cookiejar.py
M Lib/mailbox.py
M Lib/mailcap.py
M Lib/mimetypes.py
M Lib/pstats.py
M Lib/pydoc.py
M Lib/quopri.py
M Lib/shlex.py
M Lib/shutil.py
M Lib/smtplib.py
M Lib/socketserver.py
M Lib/tarfile.py
M Lib/test/test_lzma.py
M Lib/urllib/request.py
M Lib/wsgiref/handlers.py
M Lib/wsgiref/validate.py
M Lib/xdrlib.py
M Lib/xml/dom/expatbuilder.py
M Lib/xml/etree/ElementTree.py
M Lib/xml/sax/xmlreader.py
M Lib/xmlrpc/client.py
M Lib/xmlrpc/server.py
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 163cf9de279f..7f247ff47c9e 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -638,10 +638,7 @@ def read(self, size=-1):
def readall(self):
"""Read until EOF, using multiple read() call."""
res = bytearray()
- while True:
- data = self.read(DEFAULT_BUFFER_SIZE)
- if not data:
- break
+ while data := self.read(DEFAULT_BUFFER_SIZE):
res += data
if res:
return bytes(res)
diff --git a/Lib/base64.py b/Lib/base64.py
index 30796a6fd6d0..95dc7b008605 100755
--- a/Lib/base64.py
+++ b/Lib/base64.py
@@ -508,14 +508,8 @@ def b85decode(b):
def encode(input, output):
"""Encode a file; input and output are binary files."""
- while True:
- s = input.read(MAXBINSIZE)
- if not s:
- break
- while len(s) < MAXBINSIZE:
- ns = input.read(MAXBINSIZE-len(s))
- if not ns:
- break
+ while s := input.read(MAXBINSIZE):
+ while len(s) < MAXBINSIZE and (ns := input.read(MAXBINSIZE-len(s))):
s += ns
line = binascii.b2a_base64(s)
output.write(line)
@@ -523,10 +517,7 @@ def encode(input, output):
def decode(input, output):
"""Decode a file; input and output are binary files."""
- while True:
- line = input.readline()
- if not line:
- break
+ while line := input.readline():
s = binascii.a2b_base64(line)
output.write(s)
diff --git a/Lib/ctypes/_aix.py b/Lib/ctypes/_aix.py
index fc3e95cbcc88..ee790f713a9e 100644
--- a/Lib/ctypes/_aix.py
+++ b/Lib/ctypes/_aix.py
@@ -108,12 +108,8 @@ def get_ld_headers(file):
p = Popen(["/usr/bin/dump", f"-X{AIX_ABI}", "-H", file],
universal_newlines=True, stdout=PIPE, stderr=DEVNULL)
# be sure to read to the end-of-file - getting all entries
- while True:
- ld_header = get_ld_header(p)
- if ld_header:
- ldr_headers.append((ld_header, get_ld_header_info(p)))
- else:
- break
+ while ld_header := get_ld_header(p):
+ ldr_headers.append((ld_header, get_ld_header_info(p)))
p.stdout.close()
p.wait()
return ldr_headers
diff --git a/Lib/email/parser.py b/Lib/email/parser.py
index 7db4da1ff081..e94d455baa52 100644
--- a/Lib/email/parser.py
+++ b/Lib/email/parser.py
@@ -49,10 +49,7 @@ def parse(self, fp, headersonly=False):
feedparser = FeedParser(self._class, policy=self.policy)
if headersonly:
feedparser._set_headersonly()
- while True:
- data = fp.read(8192)
- if not data:
- break
+ while data := fp.read(8192):
feedparser.feed(data)
return feedparser.close()
diff --git a/Lib/ftplib.py b/Lib/ftplib.py
index c7ca8f632e1b..a56e0c308570 100644
--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -434,10 +434,7 @@ def retrbinary(self, cmd, callback, blocksize=8192, rest=None):
"""
self.voidcmd('TYPE I')
with self.transfercmd(cmd, rest) as conn:
- while 1:
- data = conn.recv(blocksize)
- if not data:
- break
+ while data := conn.recv(blocksize):
callback(data)
# shutdown ssl layer
if _SSLSocket is not None and isinstance(conn, _SSLSocket):
@@ -496,10 +493,7 @@ def storbinary(self, cmd, fp, blocksize=8192, callback=None, rest=None):
"""
self.voidcmd('TYPE I')
with self.transfercmd(cmd, rest) as conn:
- while 1:
- buf = fp.read(blocksize)
- if not buf:
- break
+ while buf := fp.read(blocksize):
conn.sendall(buf)
if callback:
callback(buf)
diff --git a/Lib/http/client.py b/Lib/http/client.py
index 0a3e950c6696..15c5cf634cf5 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -578,11 +578,7 @@ def _read_chunked(self, amt=None):
assert self.chunked != _UNKNOWN
value = []
try:
- while True:
- chunk_left = self._get_chunk_left()
- if chunk_left is None:
- break
-
+ while (chunk_left := self._get_chunk_left()) is not None:
if amt is not None and amt <= chunk_left:
value.append(self._safe_read(amt))
self.chunk_left = chunk_left - amt
@@ -998,10 +994,7 @@ def send(self, data):
encode = self._is_textIO(data)
if encode and self.debuglevel > 0:
print("encoding file using iso-8859-1")
- while 1:
- datablock = data.read(self.blocksize)
- if not datablock:
- break
+ while datablock := data.read(self.blocksize):
if encode:
datablock = datablock.encode("iso-8859-1")
sys.audit("http.client.send", self, datablock)
@@ -1031,10 +1024,7 @@ def _read_readable(self, readable):
encode = self._is_textIO(readable)
if encode and self.debuglevel > 0:
print("encoding file using iso-8859-1")
- while True:
- datablock = readable.read(self.blocksize)
- if not datablock:
- break
+ while datablock := readable.read(self.blocksize):
if encode:
datablock = datablock.encode("iso-8859-1")
yield datablock
diff --git a/Lib/http/cookiejar.py b/Lib/http/cookiejar.py
index 65c45e2b17df..b0161a86fdbb 100644
--- a/Lib/http/cookiejar.py
+++ b/Lib/http/cookiejar.py
@@ -1915,9 +1915,7 @@ def _really_load(self, f, filename, ignore_discard, ignore_expires):
"comment", "commenturl")
try:
- while 1:
- line = f.readline()
- if line == "": break
+ while (line := f.readline()) != "":
if not line.startswith(header):
continue
line = line[len(header):].strip()
@@ -2017,12 +2015,9 @@ def _really_load(self, f, filename, ignore_discard, ignore_expires):
filename)
try:
- while 1:
- line = f.readline()
+ while (line := f.readline()) != "":
rest = {}
- if line == "": break
-
# httponly is a cookie flag as defined in rfc6265
# when encoded in a netscape cookie file,
# the line is prepended with "#HttpOnly_"
diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index 70da07ed2e9e..59834a2b3b52 100644
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -1956,10 +1956,7 @@ def readlines(self, sizehint=None):
def __iter__(self):
"""Iterate over lines."""
- while True:
- line = self.readline()
- if not line:
- return
+ while line := self.readline():
yield line
def tell(self):
diff --git a/Lib/mailcap.py b/Lib/mailcap.py
index 7278ea7051fc..2f4656e854b3 100644
--- a/Lib/mailcap.py
+++ b/Lib/mailcap.py
@@ -90,9 +90,7 @@ def _readmailcapfile(fp, lineno):
the viewing command is stored with the key "view".
"""
caps = {}
- while 1:
- line = fp.readline()
- if not line: break
+ while line := fp.readline():
# Ignore comments and blank lines
if line[0] == '#' or line.strip() == '':
continue
diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index 3224363a3f2b..37228de4828d 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -217,10 +217,7 @@ def readfp(self, fp, strict=True):
list of standard types, else to the list of non-standard
types.
"""
- while 1:
- line = fp.readline()
- if not line:
- break
+ while line := fp.readline():
words = line.split()
for i in range(len(words)):
if words[i][0] == '#':
diff --git a/Lib/pstats.py b/Lib/pstats.py
index 80408313e8b2..51bcca841887 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -223,8 +223,6 @@ def get_sort_arg_defs(self):
for word, tup in self.sort_arg_dict_default.items():
fragment = word
while fragment:
- if not fragment:
- break
if fragment in dict:
bad_list[fragment] = 0
break
diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index c79ec77a8c09..0a693f45230c 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -686,9 +686,7 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}):
r'RFC[- ]?(\d+)|'
r'PEP[- ]?(\d+)|'
r'(self\.)?(\w+))')
- while True:
- match = pattern.search(text, here)
- if not match: break
+ while match := pattern.search(text, here):
start, end = match.span()
results.append(escape(text[here:start]))
diff --git a/Lib/quopri.py b/Lib/quopri.py
index 08899c5cb73a..f36cf7b3951c 100755
--- a/Lib/quopri.py
+++ b/Lib/quopri.py
@@ -67,10 +67,7 @@ def write(s, output=output, lineEnd=b'\n'):
output.write(s + lineEnd)
prevline = None
- while 1:
- line = input.readline()
- if not line:
- break
+ while line := input.readline():
outline = []
# Strip off any readline induced trailing newline
stripped = b''
@@ -126,9 +123,7 @@ def decode(input, output, header=False):
return
new = b''
- while 1:
- line = input.readline()
- if not line: break
+ while line := input.readline():
i, n = 0, len(line)
if n > 0 and line[n-1:n] == b'\n':
partial = 0; n = n-1
diff --git a/Lib/shlex.py b/Lib/shlex.py
index a91c9b022627..f4821616b62a 100644
--- a/Lib/shlex.py
+++ b/Lib/shlex.py
@@ -333,10 +333,7 @@ def quote(s):
def _print_tokens(lexer):
- while 1:
- tt = lexer.get_token()
- if not tt:
- break
+ while tt := lexer.get_token():
print("Token: " + repr(tt))
if __name__ == '__main__':
diff --git a/Lib/shutil.py b/Lib/shutil.py
index f372406a6c51..867925aa10cc 100644
--- a/Lib/shutil.py
+++ b/Lib/shutil.py
@@ -194,10 +194,7 @@ def copyfileobj(fsrc, fdst, length=0):
# Localize variable access to minimize overhead.
fsrc_read = fsrc.read
fdst_write = fdst.write
- while True:
- buf = fsrc_read(length)
- if not buf:
- break
+ while buf := fsrc_read(length):
fdst_write(buf)
def _samefile(src, dst):
diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index 05d2f8ccd73c..18c91746fd7b 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -1099,10 +1099,7 @@ def prompt(prompt):
toaddrs = prompt("To").split(',')
print("Enter message, end with ^D:")
msg = ''
- while 1:
- line = sys.stdin.readline()
- if not line:
- break
+ while line := sys.stdin.readline():
msg = msg + line
print("Message length is %d" % len(msg))
diff --git a/Lib/socketserver.py b/Lib/socketserver.py
index 30a5cfa59fe0..842d526b0119 100644
--- a/Lib/socketserver.py
+++ b/Lib/socketserver.py
@@ -292,8 +292,7 @@ def handle_request(self):
selector.register(self, selectors.EVENT_READ)
while True:
- ready = selector.select(timeout)
- if ready:
+ if selector.select(timeout):
return self._handle_request_noblock()
else:
if timeout is not None:
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index b47015f5cb6b..d686435d90ad 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1262,11 +1262,7 @@ def _proc_pax(self, tarfile):
# the newline. keyword and value are both UTF-8 encoded strings.
regex = re.compile(br"(\d+) ([^=]+)=")
pos = 0
- while True:
- match = regex.match(buf, pos)
- if not match:
- break
-
+ while match := regex.match(buf, pos):
length, keyword = match.groups()
length = int(length)
if length == 0:
@@ -2418,10 +2414,8 @@ def _load(self):
"""Read through the entire archive file and look for readable
members.
"""
- while True:
- tarinfo = self.next()
- if tarinfo is None:
- break
+ while self.next() is not None:
+ pass
self._loaded = True
def _check(self, mode=None):
diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index 145c8cfced40..18f474ba2a8b 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -825,10 +825,7 @@ def test_read_0(self):
def test_read_10(self):
with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
chunks = []
- while True:
- result = f.read(10)
- if not result:
- break
+ while result := f.read(10):
self.assertLessEqual(len(result), 10)
chunks.append(result)
self.assertEqual(b"".join(chunks), INPUT)
@@ -911,10 +908,7 @@ def test_read_bad_data(self):
def test_read1(self):
with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
blocks = []
- while True:
- result = f.read1()
- if not result:
- break
+ while result := f.read1():
blocks.append(result)
self.assertEqual(b"".join(blocks), INPUT)
self.assertEqual(f.read1(), b"")
@@ -926,10 +920,7 @@ def test_read1_0(self):
def test_read1_10(self):
with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
blocks = []
- while True:
- result = f.read1(10)
- if not result:
- break
+ while result := f.read1(10):
blocks.append(result)
self.assertEqual(b"".join(blocks), INPUT)
self.assertEqual(f.read1(), b"")
@@ -937,10 +928,7 @@ def test_read1_10(self):
def test_read1_multistream(self):
with LZMAFile(BytesIO(COMPRESSED_XZ * 5)) as f:
blocks = []
- while True:
- result = f.read1()
- if not result:
- break
+ while result := f.read1():
blocks.append(result)
self.assertEqual(b"".join(blocks), INPUT * 5)
self.assertEqual(f.read1(), b"")
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index 278aa3a14bfe..151034e6a81b 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -265,10 +265,7 @@ def urlretrieve(url, filename=None, reporthook=None, data=None):
if reporthook:
reporthook(blocknum, bs, size)
- while True:
- block = fp.read(bs)
- if not block:
- break
+ while block := fp.read(bs):
read += len(block)
tfp.write(block)
blocknum += 1
@@ -1847,10 +1844,7 @@ def retrieve(self, url, filename=None, reporthook=None, data=None):
size = int(headers["Content-Length"])
if reporthook:
reporthook(blocknum, bs, size)
- while 1:
- block = fp.read(bs)
- if not block:
- break
+ while block := fp.read(bs):
read += len(block)
tfp.write(block)
blocknum += 1
diff --git a/Lib/wsgiref/handlers.py b/Lib/wsgiref/handlers.py
index cd0916dc5553..cafe872c7aae 100644
--- a/Lib/wsgiref/handlers.py
+++ b/Lib/wsgiref/handlers.py
@@ -475,10 +475,7 @@ def _write(self,data):
from warnings import warn
warn("SimpleHandler.stdout.write() should not do partial writes",
DeprecationWarning)
- while True:
- data = data[result:]
- if not data:
- break
+ while data := data[result:]:
result = self.stdout.write(data)
def _flush(self):
diff --git a/Lib/wsgiref/validate.py b/Lib/wsgiref/validate.py
index 6044e320a474..1a1853cd63a0 100644
--- a/Lib/wsgiref/validate.py
+++ b/Lib/wsgiref/validate.py
@@ -214,10 +214,7 @@ def readlines(self, *args):
return lines
def __iter__(self):
- while 1:
- line = self.readline()
- if not line:
- return
+ while line := self.readline():
yield line
def close(self):
diff --git a/Lib/xdrlib.py b/Lib/xdrlib.py
index b56ffa59b73d..f8c2c18228da 100644
--- a/Lib/xdrlib.py
+++ b/Lib/xdrlib.py
@@ -224,9 +224,7 @@ def unpack_string(self):
def unpack_list(self, unpack_item):
list = []
- while 1:
- x = self.unpack_uint()
- if x == 0: break
+ while (x := self.unpack_uint()) != 0:
if x != 1:
raise ConversionError('0 or 1 expected, got %r' % (x,))
item = unpack_item()
diff --git a/Lib/xml/dom/expatbuilder.py b/Lib/xml/dom/expatbuilder.py
index 199c22d0af34..7dd667bf3fbe 100644
--- a/Lib/xml/dom/expatbuilder.py
+++ b/Lib/xml/dom/expatbuilder.py
@@ -200,10 +200,7 @@ def parseFile(self, file):
parser = self.getParser()
first_buffer = True
try:
- while 1:
- buffer = file.read(16*1024)
- if not buffer:
- break
+ while buffer := file.read(16*1024):
parser.Parse(buffer, False)
if first_buffer and self.document.documentElement:
self._setup_subset(buffer)
diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
index ebbe2b703bfd..df5d5191126a 100644
--- a/Lib/xml/etree/ElementTree.py
+++ b/Lib/xml/etree/ElementTree.py
@@ -566,10 +566,7 @@ def parse(self, source, parser=None):
# it with chunks.
self._root = parser._parse_whole(source)
return self._root
- while True:
- data = source.read(65536)
- if not data:
- break
+ while data := source.read(65536):
parser.feed(data)
self._root = parser.close()
return self._root
diff --git a/Lib/xml/sax/xmlreader.py b/Lib/xml/sax/xmlreader.py
index 716f22840414..e906121d23b9 100644
--- a/Lib/xml/sax/xmlreader.py
+++ b/Lib/xml/sax/xmlreader.py
@@ -120,10 +120,8 @@ def parse(self, source):
file = source.getCharacterStream()
if file is None:
file = source.getByteStream()
- buffer = file.read(self._bufsize)
- while buffer:
+ while buffer := file.read(self._bufsize):
self.feed(buffer)
- buffer = file.read(self._bufsize)
self.close()
def feed(self, data):
diff --git a/Lib/xmlrpc/client.py b/Lib/xmlrpc/client.py
index bef23f4505e0..ea8da766cb5a 100644
--- a/Lib/xmlrpc/client.py
+++ b/Lib/xmlrpc/client.py
@@ -1339,10 +1339,7 @@ def parse_response(self, response):
p, u = self.getparser()
- while 1:
- data = stream.read(1024)
- if not data:
- break
+ while data := stream.read(1024):
if self.verbose:
print("body:", repr(data))
p.feed(data)
diff --git a/Lib/xmlrpc/server.py b/Lib/xmlrpc/server.py
index 0c4b558045a9..4dddb1d10e08 100644
--- a/Lib/xmlrpc/server.py
+++ b/Lib/xmlrpc/server.py
@@ -720,9 +720,7 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}):
r'RFC[- ]?(\d+)|'
r'PEP[- ]?(\d+)|'
r'(self\.)?((?:\w|\.)+))\b')
- while 1:
- match = pattern.search(text, here)
- if not match: break
+ while match := pattern.search(text, here):
start, end = match.span()
results.append(escape(text[here:start]))
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