This is an archive of the discontinued Mercurial Phabricator instance.

Differential D5019

pager: disable auto pager if we think it doesn't support F, R, X
AbandonedPublic

Authored by spectral on Oct 12 2018, 1:44 PM.

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baymax
Group Reviewers
hg-reviewers

Diff Detail

Repository
rHG Mercurial
Lint
Lint Skipped
Unit
Unit Tests Skipped

Event Timeline

spectral created this revision.Oct 12 2018, 1:44 PM
indygreg added a subscriber: indygreg.Oct 12 2018, 2:24 PM

I need to review this on a fresher brain. But I'll be honest, I'm not sure how I feel about this.

Do you know of other programs that jump through similar hoops to properly set up a pager?

mercurial/ui.py
1120

Won't this iterate integers on Python 3?

baymax requested changes to this revision.Jan 24 2020, 12:32 PM

There seems to have been no activities on this Diff for the past 3 Months.

By policy, we are automatically moving it out of the need-review state.

Please, move it back to need-review without hesitation if this diff should still be discussed.

:baymax:need-review-idle:

This revision now requires changes to proceed.Jan 24 2020, 12:32 PM
spectral abandoned this revision.Oct 29 2021, 5:44 PM

Revision Contents
Changeset List

PathPackages
Mmercurial/ui.py (164 lines)

Diff 11937

mercurial/ui.py

def _isatty(self, fh): def _isatty(self, fh):
if self.configbool('ui', 'nontty'): if self.configbool('ui', 'nontty'):
return False return False
return procutil.isatty(fh) return procutil.isatty(fh)
def disablepager(self): def disablepager(self):
self._disablepager = True self._disablepager = True
def _checkpager(self, explicitpager, pagercmd, pagerenv):
"""Check that the pager can handle things properly.
>>> u = ui()
>>> savedenviron = encoding.environ
>>> u._checkpager(True, '', {'LESS': '-FRX'})
True
>>> u._checkpager(True, 'less -F', {'LESS': '-FRX'})
True
>>> encoding.environ['PAGER'] = 'more'
>>> encoding.environ['LESS'] = '-F'
>>> u._checkpager(False, 'sensible-pager', {})
True
>>> encoding.environ['PAGER'] = 'less -F'
>>> encoding.environ['LESS'] = '-FRM'
>>> u._checkpager(False, 'sensible-pager', {})
False
>>> encoding.environ['PAGER'] = 'less -X'
>>> encoding.environ['LESS'] = '-FRM'
>>> u._checkpager(False, 'sensible-pager', {})
True
>>> encoding.environ['LESS'] = '-F'
>>> u._checkpager(False, 'less -RX', {})
True
>>> u._checkpager(False, 'less -FrX', {})
True
>>> encoding.environ = savedenviron
>>> u._checkpager(False, 'less -RX', {'LESS': '-FRX'})
True
>>> u._checkpager(False, 'less -RX', {'LESS': '-FRX'})
True
>>> u._checkpager(False, '/bin/less --no-init --quit-if-one-screen --RAW-CONTROL-CHARS', {'LESS': '-FRX'})
True
>>> u._checkpager(False, '/bin/less --no-init --quit-if-one-screen --raw-control-chars', {'LESS': '-FRX'})
True
>>> u._checkpager(False, '/bin/less --no-init --quit-if-one-screen', {'LESS': '-FRX'})
True
>>> u._checkpager(False, 'less --unrelated -FRX', {'LESS': '-FRX'})
True
>>> u._checkpager(False, '/bin/less', {'LESS': 'Dn9.2$FRXDs4.1'})
True
>>> u._checkpager(False, '/bin/less', {'LESS': 'Dn9.2$Ds4.1FRX'})
False
>>> u._checkpager(False, '/bin/less', {'LESS': 'FRXDn9.2$Ds4.1'})
True
>>> encoding.environ['TERM'] = 'tmux'
>>> u._checkpager(False, 'less -FRX', {'LESS': '-FRX'})
False
>>> u._checkpager(False, 'less -FrX', {'LESS': '-FRX'})
True
>>> encoding.environ['TERM'] = 'screen-256color-bce'
>>> u._checkpager(False, 'less', {'LESS': '-FRX'})
False
>>> u._checkpager(False, 'less -r', {'LESS': '-FRX'})
True
"""
if explicitpager:
return True # Trust the user
if pagercmd == 'sensible-pager':
# Looks like we're on a Debian system. This should respect PAGER
# and the alternatives system, but we're only checking PAGER here,
# and assuming it's 'less' otherwise. The only time that we should
# misbehave here and *de*activate the pager is if the user is using
# the Debian alternatives system to pick a different pager AND the
# user has the $LESS environment variable set.
pagercmd = encoding.environ.get('PAGER', 'less')
pager = pycompat.shlexsplit(pagercmd)
if not pager:
return True # No idea how this could happen, but don't error
if not pager[0].endswith('less'):
return True # We don't verify non-less pagers right now
# The options that were detected as being enabled
lessoptions = set()
lessenvvar = pagerenv.get('LESS', encoding.environ.get('LESS', None))
assert lessenvvar is not None
# Search the $LESS environment variable for the options we care about
# (if the user does not have the variable set, then the LESS value from
# rcutil.defaultpagerenv will be used).
instrval = False
strvalargs = 'DkoOpPtT'
# Important: if you add any additional lower-case letters to this, check
# the calls below that uppercase things.
desiredargs = 'FRrX'
for ch in lessenvvar:
indygregUnsubmitted
Not Done

Won't this iterate integers on Python 3?

indygreg: Won't this iterate integers on Python 3?
if ch == '-':
continue
if not instrval and ch in strvalargs:
# These flags are documented to take a string value, so we need
# to start ignoring characters until it's over (a $ character)
instrval = True
continue
if instrval:
if ch == '$':
instrval = False
continue
if ch == '$':
# Encountered a $ outside of a string. Looks like we may have
# missed an option that takes a string argument? Let's just
# trust the user knows what they're doing.
return True
if ch in desiredargs:
lessoptions.add(ch.upper())
# This only works for 'r' implying 'R'.
lessoptions.add(ch)
# Really hacky commandline parser - search the commandline (as provided
# in .hgrc, $PAGER, etc.) for the flags.
for arg in pager:
if arg == '--quit-if-one-screen':
lessoptions.add('F')
continue
if arg == '--RAW-CONTROL-CHARS':
lessoptions.add('R')
continue
if arg == '--raw-control-chars':
lessoptions.add('r')
lessoptions.add('R')
continue
if arg == '--no-init':
lessoptions.add('X')
continue
if arg.startswith('-') and not arg.startswith('--'):
for ch in arg:
if ch in strvalargs:
break
if ch in desiredargs:
lessoptions.add(ch.upper())
# This only works for 'r' implying 'R'.
lessoptions.add(ch)
continue
# If any of F, R, or X are NOT in lessoptions...
desired = {'F': 'quit if one screen',
'R': 'color support',
'X': 'avoid clearing screen'}
missing = set(desired.keys()) - lessoptions
if missing:
self.debug(
'NOT enabling pager, config appears to be missing:\n - %s\n'
% '\n - '.join(desired[k] for k in missing))
return False
# On tmux and screen, sgr0 prints ^O, which requires `less -r` (`less
# -R` is insufficient), so refuse to use the pager in that case too.
term = encoding.environ.get('TERM', '')
if term in ['tmux', 'tmux-256color', 'screen'] or \
term.startswith('screen-'):
if 'r' not in lessoptions:
self.debug(
'NOT enabling pager, it might not display correctly.\n')
return False
return True
def pager(self, command): def pager(self, command):
"""Start a pager for subsequent command output. """Start a pager for subsequent command output.
Commands which produce a long stream of output should call Commands which produce a long stream of output should call
this function to activate the user's preferred pagination this function to activate the user's preferred pagination
mechanism (which may be no pager). Calling this function mechanism (which may be no pager). Calling this function
precludes any future use of interactive functionality, such as precludes any future use of interactive functionality, such as
prompting the user or activating curses. prompting the user or activating curses.
Args: Args:
command: The full, non-aliased name of the command. That is, "log" command: The full, non-aliased name of the command. That is, "log"
not "history, "summary" not "summ", etc. not "history, "summary" not "summ", etc.
""" """
if (self._disablepager if (self._disablepager
or self.pageractive): or self.pageractive):
# how pager should do is already determined # how pager should do is already determined
return return
if not command.startswith('internal-always-') and ( explicitpager = command.startswith('internal-always-')
if not explicitpager and (
# explicit --pager=on (= 'internal-always-' prefix) should # explicit --pager=on (= 'internal-always-' prefix) should
# take precedence over disabling factors below # take precedence over disabling factors below
command in self.configlist('pager', 'ignore') command in self.configlist('pager', 'ignore')
or not self.configbool('ui', 'paginate') or not self.configbool('ui', 'paginate')
or not self.configbool('pager', 'attend-' + command, True) or not self.configbool('pager', 'attend-' + command, True)
or encoding.environ.get('TERM') == 'dumb' or encoding.environ.get('TERM') == 'dumb'
# TODO: if we want to allow HGPLAINEXCEPT=pager, # TODO: if we want to allow HGPLAINEXCEPT=pager,
# formatted() will need some adjustment. # formatted() will need some adjustment.
if not pagercmd: if not pagercmd:
return return
pagerenv = {} pagerenv = {}
for name, value in rcutil.defaultpagerenv().items(): for name, value in rcutil.defaultpagerenv().items():
if name not in encoding.environ: if name not in encoding.environ:
pagerenv[name] = value pagerenv[name] = value
if not self._checkpager(explicitpager, pagercmd, pagerenv):
return
self.debug('starting pager for command %r\n' % command) self.debug('starting pager for command %r\n' % command)
self.flush() self.flush()
wasformatted = self.formatted() wasformatted = self.formatted()
if util.safehasattr(signal, "SIGPIPE"): if util.safehasattr(signal, "SIGPIPE"):
signal.signal(signal.SIGPIPE, _catchterm) signal.signal(signal.SIGPIPE, _catchterm)
if self._runpager(pagercmd, pagerenv): if self._runpager(pagercmd, pagerenv):
self.pageractive = True self.pageractive = True