#! /usr/bin/env python """fixdiv - tool to fix division operators. To use this tool, first run `python -Qwarnall yourscript.py 2>warnings'.This runs the script `yourscript.py' while writing warning messagesabout all uses of the classic division operator to the file`warnings'.  The warnings look like this:   <file>:<line>: DeprecationWarning: classic <type> division The warnings are written to stderr, so you must use `2>' for the I/Oredirect.  I know of no way to redirect stderr on Windows in a DOSbox, so you will have to modify the script to set sys.stderr to somekind of log file if you want to do this on Windows. The warnings are not limited to the script; modules imported by thescript may also trigger warnings.  In fact a useful technique is towrite a test script specifically intended to exercise all code in aparticular module or set of modules. Then run `python fixdiv.py warnings'.  This first reads the warnings,looking for classic division warnings, and sorts them by file name andline number.  Then, for each file that received at least one warning,it parses the file and tries to match the warnings up to the divisionoperators found in the source code.  If it is successful, it writesits findings to stdout, preceded by a line of dashes and a line of theform:   Index: <file> If the only findings found are suggestions to change a / operator intoa // operator, the output is acceptable input for the Unix 'patch'program. Here are the possible messages on stdout (N stands for a line number): - A plain-diff-style change ('NcN', a line marked by '<', a line  containing '---', and a line marked by '>'):   A / operator was found that should be changed to //.  This is the  recommendation when only int and/or long arguments were seen. - 'True division / operator at line N' and a line marked by '=':   A / operator was found that can remain unchanged.  This is the  recommendation when only float and/or complex arguments were seen. - 'Ambiguous / operator (..., ...) at line N', line marked by '?':   A / operator was found for which int or long as well as float or  complex arguments were seen.  This is highly unlikely; if it occurs,  you may have to restructure the code to keep the classic semantics,  or maybe you don't care about the classic semantics. - 'No conclusive evidence on line N', line marked by '*':   A / operator was found for which no warnings were seen.  This could  be code that was never executed, or code that was only executed  with user-defined objects as arguments.  You will have to  investigate further.  Note that // can be overloaded separately from  /, using __floordiv__.  True division can also be separately  overloaded, using __truediv__.  Classic division should be the same  as either of those.  (XXX should I add a warning for division on  user-defined objects, to disambiguate this case from code that was  never executed?) - 'Phantom ... warnings for line N', line marked by '*':   A warning was seen for a line not containing a / operator.  The most  likely cause is a warning about code executed by 'exec' or eval()  (see note below), or an indirect invocation of the / operator, for  example via the div() function in the operator module.  It could  also be caused by a change to the file between the time the test  script was run to collect warnings and the time fixdiv was run. - 'More than one / operator in line N'; or  'More than one / operator per statement in lines N-N':   The scanner found more than one / operator on a single line, or in a  statement split across multiple lines.  Because the warnings  framework doesn't (and can't) show the offset within the line, and  the code generator doesn't always give the correct line number for  operations in a multi-line statement, we can't be sure whether all  operators in the statement were executed.  To be on the safe side,  by default a warning is issued about this case.  In practice, these  cases are usually safe, and the -m option suppresses these warning. - 'Can't find the / operator in line N', line marked by '*':   This really shouldn't happen.  It means that the tokenize module  reported a '/' operator but the line it returns didn't contain a '/'  character at the indicated position. - 'Bad warning for line N: XYZ', line marked by '*':   This really shouldn't happen.  It means that a 'classic XYZ  division' warning was read with XYZ being something other than  'int', 'long', 'float', or 'complex'. Notes: - The augmented assignment operator /= is handled the same way as the  / operator. - This tool never looks at the // operator; no warnings are ever  generated for use of this operator. - This tool never looks at the / operator when a future division  statement is in effect; no warnings are generated in this case, and  because the tool only looks at files for which at least one classic  division warning was seen, it will never look at files containing a  future division statement. - Warnings may be issued for code not read from a file, but executed  using an exec statement or the eval() function.  These may have  <string> in the filename position, in which case the fixdiv script  will attempt and fail to open a file named '<string>' and issue a  warning about this failure; or these may be reported as 'Phantom'  warnings (see above).  You're on your own to deal with these.  You  could make all recommended changes and add a future division  statement to all affected files, and then re-run the test script; it  should not issue any warnings.  If there are any, and you have a  hard time tracking down where they are generated, you can use the  -Werror option to force an error instead of a first warning,  generating a traceback. - The tool should be run from the same directory as that from which  the original script was run, otherwise it won't be able to open  files given by relative pathnames.""" import sysimport getoptimport reimport tokenize multi_ok = 0 def main():    try:        opts, args = getopt.getopt(sys.argv[1:], "hm")    except getopt.error, msg:        usage(msg)        return 2    for o, a in opts:        if o == "-h":            print __doc__            return        if o == "-m":            global multi_ok            multi_ok = 1    if not args:        usage("at least one file argument is required")        return 2    if args[1:]:        sys.stderr.write("%s: extra file arguments ignored\n", sys.argv[0])    warnings = readwarnings(args[0])    if warnings is None:        return 1    files = warnings.keys()    if not files:        print "No classic division warnings read from", args[0]        return    files.sort()    exit = None    for filename in files:        x = process(filename, warnings[filename])        exit = exit or x    return exit def usage(msg):    sys.stderr.write("%s: %s\n" % (sys.argv[0], msg))    sys.stderr.write("Usage: %s [-m] warnings\n" % sys.argv[0])    sys.stderr.write("Try `%s -h' for more information.\n" % sys.argv[0]) PATTERN = ("^(.+?):(\d+): DeprecationWarning: "           "classic (int|long|float|complex) division$") def readwarnings(warningsfile):    prog = re.compile(PATTERN)    try:        f = open(warningsfile)    except IOError, msg:        sys.stderr.write("can't open: %s\n" % msg)        return    warnings = {}    while 1:        line = f.readline()        if not line:            break        m = prog.match(line)        if not m:            if line.find("division") >= 0:                sys.stderr.write("Warning: ignored input " + line)            continue        filename, lineno, what = m.groups()        list = warnings.get(filename)        if list is None:            warnings[filename] = list = []        list.append((int(lineno), intern(what)))    f.close()    return warnings def process(filename, list):    print "-"*70    assert list # if this fails, readwarnings() is broken    try:        fp = open(filename)    except IOError, msg:        sys.stderr.write("can't open: %s\n" % msg)        return 1    print "Index:", filename    f = FileContext(fp)    list.sort()    index = 0 # list[:index] has been processed, list[index:] is still to do    g = tokenize.generate_tokens(f.readline)    while 1:        startlineno, endlineno, slashes = lineinfo = scanline(g)        if startlineno is None:            break        assert startlineno <= endlineno is not None        orphans = []        while index < len(list) and list[index][0] < startlineno:            orphans.append(list[index])            index += 1        if orphans:            reportphantomwarnings(orphans, f)        warnings = []        while index < len(list) and list[index][0] <= endlineno:            warnings.append(list[index])            index += 1        if not slashes and not warnings:            pass        elif slashes and not warnings:            report(slashes, "No conclusive evidence")        elif warnings and not slashes:            reportphantomwarnings(warnings, f)        else:            if len(slashes) > 1:                if not multi_ok:                    rows = []                    lastrow = None                    for (row, col), line in slashes:                        if row == lastrow:                            continue                        rows.append(row)                        lastrow = row                    assert rows                    if len(rows) == 1:                        print "*** More than one / operator in line", rows[0]                    else:                        print "*** More than one / operator per statement",                        print "in lines %d-%d" % (rows[0], rows[-1])            intlong = []            floatcomplex = []            bad = []            for lineno, what in warnings:                if what in ("int", "long"):                    intlong.append(what)                elif what in ("float", "complex"):                    floatcomplex.append(what)                else:                    bad.append(what)            lastrow = None            for (row, col), line in slashes:                if row == lastrow:                    continue                lastrow = row                line = chop(line)                if line[col:col+1] != "/":                    print "*** Can't find the / operator in line %d:" % row                    print "*", line                    continue                if bad:                    print "*** Bad warning for line %d:" % row, bad                    print "*", line                elif intlong and not floatcomplex:                    print "%dc%d" % (row, row)                    print "<", line                    print "---"                    print ">", line[:col] + "/" + line[col:]                elif floatcomplex and not intlong:                    print "True division / operator at line %d:" % row                    print "=", line                elif intlong and floatcomplex:                    print "*** Ambiguous / operator (%s, %s) at line %d:" % (                        "|".join(intlong), "|".join(floatcomplex), row)                    print "?", line    fp.close() def reportphantomwarnings(warnings, f):    blocks = []    lastrow = None    lastblock = None    for row, what in warnings:        if row != lastrow:            lastblock = [row]            blocks.append(lastblock)        lastblock.append(what)    for block in blocks:        row = block[0]        whats = "/".join(block[1:])        print "*** Phantom %s warnings for line %d:" % (whats, row)        f.report(row, mark="*") def report(slashes, message):    lastrow = None    for (row, col), line in slashes:        if row != lastrow:            print "*** %s on line %d:" % (message, row)            print "*", chop(line)            lastrow = row class FileContext:    def __init__(self, fp, window=5, lineno=1):        self.fp = fp        self.window = 5        self.lineno = 1        self.eoflookahead = 0        self.lookahead = []        self.buffer = []    def fill(self):        while len(self.lookahead) < self.window and not self.eoflookahead:            line = self.fp.readline()            if not line:                self.eoflookahead = 1                break            self.lookahead.append(line)    def readline(self):        self.fill()        if not self.lookahead:            return ""        line = self.lookahead.pop(0)        self.buffer.append(line)        self.lineno += 1        return line    def truncate(self):        del self.buffer[-window:]    def __getitem__(self, index):        self.fill()        bufstart = self.lineno - len(self.buffer)        lookend = self.lineno + len(self.lookahead)        if bufstart <= index < self.lineno:            return self.buffer[index - bufstart]        if self.lineno <= index < lookend:            return self.lookahead[index - self.lineno]        raise KeyError    def report(self, first, last=None, mark="*"):        if last is None:            last = first        for i in range(first, last+1):            try:                line = self[first]            except KeyError:                line = "<missing line>"            print mark, chop(line) def scanline(g):    slashes = []    startlineno = None    endlineno = None    for type, token, start, end, line in g:        endlineno = end[0]        if startlineno is None:            startlineno = endlineno        if token in ("/", "/="):            slashes.append((start, line))        if type == tokenize.NEWLINE:            break    return startlineno, endlineno, slashes def chop(line):    if line.endswith("\n"):        return line[:-1]    else:        return line if __name__ == "__main__":    sys.exit(main())