doc/check-seclevel.py

rust-cpython: mark all PyLeaked methods as unsafe

Unfortunately, these methods can be abused to obtain the inner 'static
reference. The simplest (pseudo-code) example is:

  let leaked: PyLeaked<&'static _> = shared.leak_immutable();
  let static_ref: &'static _ = &*leaked.try_borrow(py)?;
      // PyLeakedRef::deref() tries to bound the lifetime to itself, but
      // the underlying data is a &'static reference, so the returned
      // reference can be &'static.

This problem can be easily fixed by coercing the lifetime, but there are
many other ways to achieve that, and there wouldn't be a generic solution:

  let leaked: PyLeaked<&'static [_]> = shared.leak_immutable();
  let leaked_iter: PyLeaked<slice::Iter<'static, _>>
      = unsafe { leaked.map(|v| v.iter()) };
  let static_slice: &'static [_] = leaked_iter.try_borrow(py)?.as_slice();

So basically I failed to design the safe borrowing interface. Maybe we'll
instead have to add much more restricted interface on top of the unsafe
PyLeaked methods? For instance, Iterator::next() could be implemented if
its Item type is not &'a (where 'a may be cheated.)

Anyway, this seems not an easy issue, so it's probably better to leave the
current interface as unsafe, and get broader comments while upstreaming this
feature.

#!/usr/bin/env python
#
# checkseclevel - checking section title levels in each online help document

from __future__ import absolute_import

import optparse
import os
import sys

# import from the live mercurial repo
os.environ['HGMODULEPOLICY'] = 'py'
sys.path.insert(0, "..")
from mercurial import demandimport

demandimport.enable()
from mercurial import (
    commands,
    extensions,
    help,
    minirst,
    ui as uimod,
)

table = commands.table
helptable = help.helptable

level2mark = [b'"', b'=', b'-', b'.', b'#']
reservedmarks = [b'"']

mark2level = {}
for m, l in zip(level2mark, range(len(level2mark))):
    if m not in reservedmarks:
        mark2level[m] = l

initlevel_topic = 0
initlevel_cmd = 1
initlevel_ext = 1
initlevel_ext_cmd = 3


def showavailables(ui, initlevel):
    avail = '    available marks and order of them in this help: %s\n' % (
        ', '.join(['%r' % (m * 4) for m in level2mark[initlevel + 1 :]])
    )
    ui.warn(avail.encode('utf-8'))


def checkseclevel(ui, doc, name, initlevel):
    ui.notenoi18n('checking "%s"\n' % name)
    if not isinstance(doc, bytes):
        doc = doc.encode('utf-8')
    blocks, pruned = minirst.parse(doc, 0, ['verbose'])
    errorcnt = 0
    curlevel = initlevel
    for block in blocks:
        if block[b'type'] != b'section':
            continue
        mark = block[b'underline']
        title = block[b'lines'][0]
        if (mark not in mark2level) or (mark2level[mark] <= initlevel):
            ui.warn(
                (
                    'invalid section mark %r for "%s" of %s\n'
                    % (mark * 4, title, name)
                ).encode('utf-8')
            )
            showavailables(ui, initlevel)
            errorcnt += 1
            continue
        nextlevel = mark2level[mark]
        if curlevel < nextlevel and curlevel + 1 != nextlevel:
            ui.warnnoi18n(
                'gap of section level at "%s" of %s\n' % (title, name)
            )
            showavailables(ui, initlevel)
            errorcnt += 1
            continue
        ui.notenoi18n(
            'appropriate section level for "%s %s"\n'
            % (mark * (nextlevel * 2), title)
        )
        curlevel = nextlevel

    return errorcnt


def checkcmdtable(ui, cmdtable, namefmt, initlevel):
    errorcnt = 0
    for k, entry in cmdtable.items():
        name = k.split(b"|")[0].lstrip(b"^")
        if not entry[0].__doc__:
            ui.notenoi18n(
                'skip checking %s: no help document\n' % (namefmt % name)
            )
            continue
        errorcnt += checkseclevel(
            ui, entry[0].__doc__, namefmt % name, initlevel
        )
    return errorcnt


def checkhghelps(ui):
    errorcnt = 0
    for h in helptable:
        names, sec, doc = h[0:3]
        if callable(doc):
            doc = doc(ui)
        errorcnt += checkseclevel(
            ui, doc, '%s help topic' % names[0], initlevel_topic
        )

    errorcnt += checkcmdtable(ui, table, '%s command', initlevel_cmd)

    for name in sorted(
        list(extensions.enabled()) + list(extensions.disabled())
    ):
        mod = extensions.load(ui, name, None)
        if not mod.__doc__:
            ui.notenoi18n(
                'skip checking %s extension: no help document\n' % name
            )
            continue
        errorcnt += checkseclevel(
            ui, mod.__doc__, '%s extension' % name, initlevel_ext
        )

        cmdtable = getattr(mod, 'cmdtable', None)
        if cmdtable:
            errorcnt += checkcmdtable(
                ui,
                cmdtable,
                '%%s command of %s extension' % name,
                initlevel_ext_cmd,
            )
    return errorcnt


def checkfile(ui, filename, initlevel):
    if filename == '-':
        filename = 'stdin'
        doc = sys.stdin.read()
    else:
        with open(filename) as fp:
            doc = fp.read()

    ui.notenoi18n(
        'checking input from %s with initlevel %d\n' % (filename, initlevel)
    )
    return checkseclevel(ui, doc, 'input from %s' % filename, initlevel)


def main():
    optparser = optparse.OptionParser(
        """%prog [options]

This checks all help documents of Mercurial (topics, commands,
extensions and commands of them), if no file is specified by --file
option.
"""
    )
    optparser.add_option(
        "-v", "--verbose", help="enable additional output", action="store_true"
    )
    optparser.add_option(
        "-d", "--debug", help="debug mode", action="store_true"
    )
    optparser.add_option(
        "-f",
        "--file",
        help="filename to read in (or '-' for stdin)",
        action="store",
        default="",
    )

    optparser.add_option(
        "-t",
        "--topic",
        help="parse file as help topic",
        action="store_const",
        dest="initlevel",
        const=0,
    )
    optparser.add_option(
        "-c",
        "--command",
        help="parse file as help of core command",
        action="store_const",
        dest="initlevel",
        const=1,
    )
    optparser.add_option(
        "-e",
        "--extension",
        help="parse file as help of extension",
        action="store_const",
        dest="initlevel",
        const=1,
    )
    optparser.add_option(
        "-C",
        "--extension-command",
        help="parse file as help of extension command",
        action="store_const",
        dest="initlevel",
        const=3,
    )

    optparser.add_option(
        "-l",
        "--initlevel",
        help="set initial section level manually",
        action="store",
        type="int",
        default=0,
    )

    (options, args) = optparser.parse_args()

    ui = uimod.ui.load()
    ui.setconfig(b'ui', b'verbose', options.verbose, b'--verbose')
    ui.setconfig(b'ui', b'debug', options.debug, b'--debug')

    if options.file:
        if checkfile(ui, options.file, options.initlevel):
            sys.exit(1)
    else:
        if checkhghelps(ui):
            sys.exit(1)


if __name__ == "__main__":
    main()