view tests/test-ui-verbosity.py @ 14007:d764463b433e

atomictempfile: avoid infinite recursion in __del__().

The problem is that a programmer using atomictempfile directly can
make an innocent everyday mistake -- not enough args to the
constructor -- which escalates badly.  You would expect a simple
TypeError crash in that case, but you actually get an infinite
recursion that is surprisingly difficult to kill: it happens between
__del__() and __getattr__(), and Python does not handle infinite
recursion from __del__() well.

The fix is to not implement __getattr__(), but instead assign instance
attributes for the methods we wish to delegate to the builtin file
type: write() and fileno(). I've audited mercurial.* and hgext.* and
found no users of atomictempfile using methods other than write() and
rename(). I audited third-party extensions and found one (snap)
passing an atomictempfile to util.fstat(), so I also threw in
fileno().

The last time I submitted a similar patch, Matt proposed that we make
atomictempfile a subclass of file instead of wrapping it. Rejected on
grounds of unnecessary complexity: for one thing, it would make the
Windows implementation of posixfile quite a bit more complex. It would
have to become a subclass of file rather than a simple function -- but
since it's written in C, this is non-obvious and non-trivial.
Furthermore, there's nothing wrong with wrapping objects and
delegating methods: it's a well-established pattern that works just
fine in many cases. Subclassing is not the answer to all of life's
problems.

import os
from mercurial import ui

hgrc = os.environ['HGRCPATH']
f = open(hgrc)
basehgrc = f.read()
f.close()

print '      hgrc settings    command line options      final result   '
print '    quiet verbo debug   quiet verbo debug      quiet verbo debug'

for i in xrange(64):
    hgrc_quiet   = bool(i & 1<<0)
    hgrc_verbose = bool(i & 1<<1)
    hgrc_debug   = bool(i & 1<<2)
    cmd_quiet    = bool(i & 1<<3)
    cmd_verbose  = bool(i & 1<<4)
    cmd_debug    = bool(i & 1<<5)

    f = open(hgrc, 'w')
    f.write(basehgrc)
    f.write('\n[ui]\n')
    if hgrc_quiet:
        f.write('quiet = True\n')
    if hgrc_verbose:
        f.write('verbose = True\n')
    if hgrc_debug:
        f.write('debug = True\n')
    f.close()

    u = ui.ui()
    if cmd_quiet or cmd_debug or cmd_verbose:
        u.setconfig('ui', 'quiet', str(bool(cmd_quiet)))
        u.setconfig('ui', 'verbose', str(bool(cmd_verbose)))
        u.setconfig('ui', 'debug', str(bool(cmd_debug)))

    check = ''
    if u.debugflag:
        if not u.verbose or u.quiet:
            check = ' *'
    elif u.verbose and u.quiet:
        check = ' +'

    print ('%2d  %5s %5s %5s   %5s %5s %5s  ->  %5s %5s %5s%s'
           % (i, hgrc_quiet, hgrc_verbose, hgrc_debug,
              cmd_quiet, cmd_verbose, cmd_debug,
              u.quiet, u.verbose, u.debugflag, check))