tests/test-ui-verbosity.py

perf: introduce safeattrsetter to replace direct attribute assignment

Referring not-existing attribute immediately causes failure, but
assigning a value to such attribute doesn't.

For example, perf.py has code paths below, which assign a value to
not-existing attribute. This causes incorrect performance measurement,
but these code paths are executed successfully.

  - "repo._tags = None" in perftags()
    recent Mercurial has tags cache information in repo._tagscache

  - "branchmap.write = lambda repo: None" in perfbranchmap()
    branchmap cache is written out by branchcache.write() in branchmap.py

"util.safehasattr() before assignment" can avoid this issue, but might
increase mistake at "copy & paste" attribute name or so.

To centralize (1) examining existence of, (2) assigning a value to,
and (3) restoring an old value to the attribute, this patch introduces
safeattrsetter(). This is used to replace direct attribute assignment
in subsequent patches.

Encapsulation of restoring is needed to completely remove direct
attribute assignment from perf.py, even though restoring isn't needed
so often.

from __future__ import absolute_import, print_function

import os
from mercurial import (
    ui as uimod,
)

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 = uimod.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)))