tests/test-ui-color.py

tags-cache: skip the filternode step if we are not going to use it

When warming the hgtagsfnodescache, we don't need the actual result, so we can
simply skip the part that "filter" fnode we read from the cache. So provide a
quite visible speed up to the top level `hg debugupdatecache` function.

### data-env-vars.name            = mozilla-try-2023-03-22-zstd-sparse-revlog
  # benchmark.name                = hg.debug.debug-update-cache
  # bin-env-vars.hg.flavor        = default
  # bin-env-vars.hg.py-re2-module = default
  # benchmark.variants.pre-state  = warm
before: 19.947581
after:  18.916804   (-5.17%, -1.03)

import os
from mercurial import (
    dispatch,
    ui as uimod,
)
from mercurial.utils import stringutil

# ensure errors aren't buffered
testui = uimod.ui()
testui.pushbuffer()
testui.writenoi18n(b'buffered\n')
testui.warnnoi18n(b'warning\n')
testui.write_err(b'error\n')
print(stringutil.pprint(testui.popbuffer(), bprefix=True).decode('ascii'))

# test dispatch.dispatch with the same ui object
hgrc = open(os.environ["HGRCPATH"], 'wb')
hgrc.write(b'[extensions]\n')
hgrc.write(b'color=\n')
hgrc.close()

ui_ = uimod.ui.load()
ui_.setconfig(b'ui', b'formatted', b'True')

# we're not interested in the output, so write that to devnull
ui_.fout = open(os.devnull, 'wb')

# call some arbitrary command just so we go through
# color's wrapped _runcommand twice.
def runcmd():
    dispatch.dispatch(dispatch.request([b'version', b'-q'], ui_))


runcmd()
print("colored? %s" % (ui_._colormode is not None))
runcmd()
print("colored? %s" % (ui_._colormode is not None))