view doc/check-seclevel.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

#!/usr/bin/env python3
#
# 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()