[Zope-dev] Fwd: Multi-argument append() is illegal

Patrick Phalen zope@teleo.net
Fri, 3 Mar 2000 08:45:12 -0800


[Martijn Pieters, on Fri, 03 Mar 2000]

:: Using a more advanced pattern (one that weeds out most proper appends, and
:: takes multiple lines into account), plus some hand weeding, brings up the
:: following list of 'illegal' tuple appends:

[snip]


Here, courtesy of Tim Peters, is checkappend.py.It might be interesting
to see if it also turns up eight examples. I have seen a comment by
Fredrik Lundh that it may need to be run multiple times to catch
everything, but haven't drilled down to figure out why that may be true.

#! /usr/bin/env python

# Released to the public domain, by Tim Peters, 28 February 2000.

"""checkappend.py -- search for multi-argument .append() calls.

Usage:  specify one or more file or directory paths:
checkappend [-v] file_or_dir [file_or_dir] ...

Each file_or_dir is checked for multi-argument .append() calls.  When
a directory, all .py files in the directory, and recursively in its
subdirectories, are checked.

Use -v for status msgs.  Use -vv for more status msgs.

In the absence of -v, the only output is pairs of the form

filename(linenumber):
line containing the suspicious append

Note that this finds multi-argument append calls regardless of whether
they're attached to list objects.  If a module defines a class with an
append method that takes more than one argument, calls to that method
will be listed.

Note that this will not find multi-argument list.append calls made via a
bound method object.  For example, this is not caught:

somelist = []
push = somelist.append
push(1, 2, 3)
"""

__version__ = 1, 0, 0

import os
import sys
import string
import getopt
import tokenize

verbose = 0

def errprint(*args):
msg = string.join(args)
sys.stderr.write(msg)
sys.stderr.write("\n")

def main():
args = sys.argv[1:]
global verbose
try:
opts, args = getopt.getopt(sys.argv[1:], "v")
except getopt.error, msg:
errprint(msg + "\n\n" + __doc__)
return
for opt, optarg in opts:
if opt == '-v':
verbose = verbose + 1
if not args:
errprint(__doc__)
return
for arg in args:
check(arg)

def check(file):
if os.path.isdir(file) and not os.path.islink(file):
if verbose:
print "%s: listing directory" % `file`
names = os.listdir(file)
for name in names:
fullname = os.path.join(file, name)
if ((os.path.isdir(fullname) and
not os.path.islink(fullname))
or os.path.normcase(name[-3:]) == ".py"):
check(fullname)
return

try:
f = open(file)
except IOError, msg:
errprint("%s: I/O Error: %s" % (`file`, str(msg)))
return

if verbose > 1:
print "checking", `file`, "..."

ok = AppendChecker(file, f).run()
if verbose and ok:
print "%s: Clean bill of health." % `file`

[FIND_DOT,
FIND_APPEND,
FIND_LPAREN,
FIND_COMMA,
FIND_STMT]   = range(5)

class AppendChecker:
def __init__(self, fname, file):
self.fname = fname
self.file = file
self.state = FIND_DOT
self.nerrors = 0

def run(self):
try:
tokenize.tokenize(self.file.readline, self.tokeneater)
except tokenize.TokenError, msg:
errprint("%s: Token Error: %s" % (`self.fname`, str(msg)))
self.nerrors = self.nerrors + 1
return self.nerrors == 0

def tokeneater(self, type, token, start, end, line,
NEWLINE=tokenize.NEWLINE,
JUNK=(tokenize.COMMENT, tokenize.NL),
OP=tokenize.OP,
NAME=tokenize.NAME):

state = self.state

if type in JUNK:
pass

elif state is FIND_DOT:
if type is OP and token == ".":
state = FIND_APPEND

elif state is FIND_APPEND:
if type is NAME and token == "append":
self.line = line
self.lineno = start[0]
state = FIND_LPAREN
else:
state = FIND_DOT

elif state is FIND_LPAREN:
if type is OP and token == "(":
self.level = 1
state = FIND_COMMA
else:
state = FIND_DOT

elif state is FIND_COMMA:
if type is OP:
if token in ("(", "{", "["):
self.level = self.level + 1
elif token in (")", "}", "]"):
self.level = self.level - 1
if self.level == 0:
state = FIND_DOT
elif token == "," and self.level == 1:
self.nerrors = self.nerrors + 1
print "%s(%d):\n%s" % (self.fname, self.lineno,
self.line)
# don't gripe about this stmt again
state = FIND_STMT

elif state is FIND_STMT:
if type is NEWLINE:
state = FIND_DOT

else:
raise SystemError("unknown internal state '%s'" % `state`)

self.state = state

if __name__ == '__main__':
main()

# end of file