Issue #22831: Use "with" to avoid possible fd leaks.

Lib/binhex.py

@@ -229,14 +229,13 @@ def binhex(inp, out):
     finfo = getfileinfo(inp)
     ofp = BinHex(finfo, out)
 
-    ifp = io.open(inp, 'rb')
+    with io.open(inp, 'rb') as ifp:
         # XXXX Do textfile translation on non-mac systems
         while True:
             d = ifp.read(128000)
             if not d: break
             ofp.write(d)
         ofp.close_data()
-    ifp.close()
 
     ifp = openrsrc(inp, 'rb')
     while True:
@@ -449,13 +448,12 @@ def hexbin(inp, out):
     if not out:
         out = ifp.FName
 
-    ofp = io.open(out, 'wb')
+    with io.open(out, 'wb') as ofp:
         # XXXX Do translation on non-mac systems
         while True:
             d = ifp.read(128000)
             if not d: break
             ofp.write(d)
-    ofp.close()
     ifp.close_data()
 
     d = ifp.read_rsrc(128000)

Lib/cgitb.py

@@ -294,9 +294,8 @@ class Hook:
             (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
 
             try:
-                file = os.fdopen(fd, 'w')
+                with os.fdopen(fd, 'w') as file:
                     file.write(doc)
-                file.close()
                 msg = '%s contains the description of this error.' % path
             except:
                 msg = 'Tried to save traceback to %s, but failed.' % path

Lib/dbm/__init__.py

@@ -153,9 +153,9 @@ def whichdb(filename):
     except OSError:
         return None
 
+    with f:
         # Read the start of the file -- the magic number
         s16 = f.read(16)
-    f.close()
     s = s16[0:4]
 
     # Return "" if not at least 4 bytes

Lib/http/cookiejar.py

@@ -1999,7 +1999,6 @@ class MozillaCookieJar(FileCookieJar):
 
         magic = f.readline()
         if not self.magic_re.search(magic):
-            f.close()
             raise LoadError(
                 "%r does not look like a Netscape format cookies file" %
                 filename)

Lib/platform.py

@@ -163,7 +163,7 @@ def libc_ver(executable=sys.executable, lib='', version='',
         # here to work around problems with Cygwin not being
         # able to open symlinks for reading
         executable = os.path.realpath(executable)
-    f = open(executable, 'rb')
+    with open(executable, 'rb') as f:
         binary = f.read(chunksize)
         pos = 0
         while 1:
@@ -196,7 +196,6 @@ def libc_ver(executable=sys.executable, lib='', version='',
                     if threads and version[-len(threads):] != threads:
                         version = version + threads
             pos = m.end()
-    f.close()
     return lib, version
 
 def _dist_try_harder(distname, version, id):

Lib/pydoc.py

@@ -1639,9 +1639,8 @@ def writedoc(thing, forceload=0):
     try:
         object, name = resolve(thing, forceload)
         page = html.page(describe(object), html.document(object, name))
-        file = open(name + '.html', 'w', encoding='utf-8')
+        with open(name + '.html', 'w', encoding='utf-8') as file:
             file.write(page)
-        file.close()
         print('wrote', name + '.html')
     except (ImportError, ErrorDuringImport) as value:
         print(value)

Lib/sre_constants.py

@@ -182,7 +182,7 @@ if __name__ == "__main__":
         items = sorted(d)
         for item in items:
             f.write("#define %s_%s %d\n" % (prefix, item, item))
-    f = open("sre_constants.h", "w")
+    with open("sre_constants.h", "w") as f:
         f.write("""\
 /*
  * Secret Labs' Regular Expression Engine
@@ -219,5 +219,4 @@ if __name__ == "__main__":
         f.write("#define SRE_INFO_LITERAL %d\n" % SRE_INFO_LITERAL)
         f.write("#define SRE_INFO_CHARSET %d\n" % SRE_INFO_CHARSET)
 
-    f.close()
     print("done")

Lib/token.py

@@ -97,8 +97,8 @@ def _main():
     except OSError as err:
         sys.stdout.write("I/O error: %s\n" % str(err))
         sys.exit(1)
+    with fp:
         lines = fp.read().split("\n")
-    fp.close()
     prog = re.compile(
         "#define[ \t][ \t]*([A-Z0-9][A-Z0-9_]*)[ \t][ \t]*([0-9][0-9]*)",
         re.IGNORECASE)
@@ -116,8 +116,8 @@ def _main():
     except OSError as err:
         sys.stderr.write("I/O error: %s\n" % str(err))
         sys.exit(2)
+    with fp:
         format = fp.read().split("\n")
-    fp.close()
     try:
         start = format.index("#--start constants--") + 1
         end = format.index("#--end constants--")
@@ -133,8 +133,8 @@ def _main():
     except OSError as err:
         sys.stderr.write("I/O error: %s\n" % str(err))
         sys.exit(4)
+    with fp:
         fp.write("\n".join(format))
-    fp.close()
 
 
 if __name__ == "__main__":

Lib/trace.py

@@ -232,8 +232,8 @@ class CoverageResults:
         if self.infile:
             # Try to merge existing counts file.
             try:
-                counts, calledfuncs, callers = \
-                        pickle.load(open(self.infile, 'rb'))
+                with open(self.infile, 'rb') as f:
+                    counts, calledfuncs, callers = pickle.load(f)
                 self.update(self.__class__(counts, calledfuncs, callers))
             except (OSError, EOFError, ValueError) as err:
                 print(("Skipping counts file %r: %s"
@@ -361,6 +361,7 @@ class CoverageResults:
 
         n_lines = 0
         n_hits = 0
+        with outfile:
             for lineno, line in enumerate(lines, 1):
                 # do the blank/comment match to try to mark more lines
                 # (help the reader find stuff that hasn't been covered)
@@ -380,7 +381,6 @@ class CoverageResults:
                     else:
                         outfile.write("       ")
                 outfile.write(line.expandtabs(8))
-        outfile.close()
 
         return n_hits, n_lines
 

Lib/xmlrpc/client.py

@@ -1010,12 +1010,9 @@ def gzip_encode(data):
     if not gzip:
         raise NotImplementedError
     f = BytesIO()
-    gzf = gzip.GzipFile(mode="wb", fileobj=f, compresslevel=1)
+    with gzip.GzipFile(mode="wb", fileobj=f, compresslevel=1) as gzf:
         gzf.write(data)
-    gzf.close()
-    encoded = f.getvalue()
-    f.close()
-    return encoded
+    return f.getvalue()
 
 ##
 # Decode a string using the gzip content encoding such as specified by the
@@ -1036,8 +1033,7 @@ def gzip_decode(data, max_decode=20971520):
     """
     if not gzip:
         raise NotImplementedError
-    f = BytesIO(data)
-    gzf = gzip.GzipFile(mode="rb", fileobj=f)
+    with gzip.GzipFile(mode="rb", fileobj=BytesIO(data)) as gzf:
         try:
             if max_decode < 0: # no limit
                 decoded = gzf.read()
@@ -1045,8 +1041,6 @@ def gzip_decode(data, max_decode=20971520):
                 decoded = gzf.read(max_decode + 1)
         except OSError:
             raise ValueError("invalid data")
-    f.close()
-    gzf.close()
     if max_decode >= 0 and len(decoded) > max_decode:
         raise ValueError("max gzipped payload length exceeded")
     return decoded