doc/gendoc.py

push: rework the computation of fallbackheads to be correct

The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.

The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)

In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::

  e
  |
  d f
  |/
  c
  |
  b
  |
  a

The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.

I added a couple of performance related common for further investigation later
on.

#!/usr/bin/env python3
"""usage: %s DOC ...

where DOC is the name of a document
"""


import os
import sys
import textwrap

try:
    import msvcrt

    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

# This script is executed during installs and may not have C extensions
# available. Relax C module requirements.
os.environ['HGMODULEPOLICY'] = 'allow'
# import from the live mercurial repo
sys.path.insert(0, os.path.abspath(".."))
from mercurial import demandimport

demandimport.enable()

from mercurial import (
    commands,
    encoding,
    extensions,
    fancyopts,
    help,
    minirst,
    pycompat,
    ui as uimod,
)
from mercurial.i18n import (
    gettext,
    _,
)
from mercurial.utils import stringutil

table = commands.table
globalopts = commands.globalopts
helptable = help.helptable
loaddoc = help.loaddoc


def get_desc(docstr):
    if not docstr:
        return b"", b""
    # sanitize
    docstr = docstr.strip(b"\n")
    docstr = docstr.rstrip()
    shortdesc = docstr.splitlines()[0].strip()

    i = docstr.find(b"\n")
    if i != -1:
        desc = docstr[i + 2 :]
    else:
        desc = shortdesc

    desc = textwrap.dedent(desc.decode('latin1')).encode('latin1')

    return (shortdesc, desc)


def get_opts(opts):
    for opt in opts:
        if len(opt) == 5:
            shortopt, longopt, default, desc, optlabel = opt
        else:
            shortopt, longopt, default, desc = opt
            optlabel = _(b"VALUE")
        allopts = []
        if shortopt:
            allopts.append(b"-%s" % shortopt)
        if longopt:
            allopts.append(b"--%s" % longopt)
        if isinstance(default, list):
            allopts[-1] += b" <%s[+]>" % optlabel
        elif (default is not None) and not isinstance(default, bool):
            allopts[-1] += b" <%s>" % optlabel
        if b'\n' in desc:
            # only remove line breaks and indentation
            desc = b' '.join(l.lstrip() for l in desc.split(b'\n'))
        if isinstance(default, fancyopts.customopt):
            default = default.getdefaultvalue()
        if default:
            default = stringutil.forcebytestr(default)
            desc += _(b" (default: %s)") % default
        yield (b", ".join(allopts), desc)


def get_cmd(cmd, cmdtable):
    d = {}
    attr = cmdtable[cmd]
    cmds = cmd.lstrip(b"^").split(b"|")

    d[b'cmd'] = cmds[0]
    d[b'aliases'] = cmd.split(b"|")[1:]
    d[b'desc'] = get_desc(gettext(pycompat.getdoc(attr[0])))
    d[b'opts'] = list(get_opts(attr[1]))

    s = b'hg ' + cmds[0]
    if len(attr) > 2:
        if not attr[2].startswith(b'hg'):
            s += b' ' + attr[2]
        else:
            s = attr[2]
    d[b'synopsis'] = s.strip()

    return d


def showdoc(ui):
    # print options
    ui.write(minirst.section(_(b"Options")))
    multioccur = False
    for optstr, desc in get_opts(globalopts):
        ui.write(b"%s\n    %s\n\n" % (optstr, desc))
        if optstr.endswith(b"[+]>"):
            multioccur = True
    if multioccur:
        ui.write(_(b"\n[+] marked option can be specified multiple times\n"))
        ui.write(b"\n")

    # print cmds
    ui.write(minirst.section(_(b"Commands")))
    commandprinter(ui, table, minirst.subsection, minirst.subsubsection)

    # print help topics
    # The config help topic is included in the hgrc.5 man page.
    helpprinter(ui, helptable, minirst.section, exclude=[b'config'])

    ui.write(minirst.section(_(b"Extensions")))
    ui.write(
        _(
            b"This section contains help for extensions that are "
            b"distributed together with Mercurial. Help for other "
            b"extensions is available in the help system."
        )
    )
    ui.write(
        (
            b"\n\n"
            b".. contents::\n"
            b"   :class: htmlonly\n"
            b"   :local:\n"
            b"   :depth: 1\n\n"
        )
    )

    for extensionname in sorted(allextensionnames()):
        mod = extensions.load(ui, extensionname, None)
        ui.write(minirst.subsection(extensionname))
        ui.write(b"%s\n\n" % gettext(pycompat.getdoc(mod)))
        cmdtable = getattr(mod, 'cmdtable', None)
        if cmdtable:
            ui.write(minirst.subsubsection(_(b'Commands')))
            commandprinter(
                ui,
                cmdtable,
                minirst.subsubsubsection,
                minirst.subsubsubsubsection,
            )


def showtopic(ui, topic):
    extrahelptable = [
        ([b"common"], b'', loaddoc(b'common'), help.TOPIC_CATEGORY_MISC),
        ([b"hg.1"], b'', loaddoc(b'hg.1'), help.TOPIC_CATEGORY_CONFIG),
        ([b"hg-ssh.8"], b'', loaddoc(b'hg-ssh.8'), help.TOPIC_CATEGORY_CONFIG),
        (
            [b"hgignore.5"],
            b'',
            loaddoc(b'hgignore.5'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
        ([b"hgrc.5"], b'', loaddoc(b'hgrc.5'), help.TOPIC_CATEGORY_CONFIG),
        (
            [b"hgignore.5.gendoc"],
            b'',
            loaddoc(b'hgignore'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
        (
            [b"hgrc.5.gendoc"],
            b'',
            loaddoc(b'config'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
    ]
    helpprinter(ui, helptable + extrahelptable, None, include=[topic])


def helpprinter(ui, helptable, sectionfunc, include=[], exclude=[]):
    for h in helptable:
        names, sec, doc = h[0:3]
        if exclude and names[0] in exclude:
            continue
        if include and names[0] not in include:
            continue
        for name in names:
            ui.write(b".. _%s:\n" % name)
        ui.write(b"\n")
        if sectionfunc:
            ui.write(sectionfunc(sec))
        if callable(doc):
            doc = doc(ui)
        ui.write(doc)
        ui.write(b"\n")


def commandprinter(ui, cmdtable, sectionfunc, subsectionfunc):
    """Render restructuredtext describing a list of commands and their
    documentations, grouped by command category.

    Args:
      ui: UI object to write the output to
      cmdtable: a dict that maps a string of the command name plus its aliases
        (separated with pipes) to a 3-tuple of (the command's function, a list
        of its option descriptions, and a string summarizing available
        options). Example, with aliases added for demonstration purposes:

          'phase|alias1|alias2': (
             <function phase at 0x7f0816b05e60>,
             [ ('p', 'public', False, 'set changeset phase to public'),
               ...,
               ('r', 'rev', [], 'target revision', 'REV')],
             '[-p|-d|-s] [-f] [-r] [REV...]'
          )
      sectionfunc: minirst function to format command category headers
      subsectionfunc: minirst function to format command headers
    """
    h = {}
    for c, attr in cmdtable.items():
        f = c.split(b"|")[0]
        f = f.lstrip(b"^")
        h[f] = c
    cmds = h.keys()

    def helpcategory(cmd):
        """Given a canonical command name from `cmds` (above), retrieve its
        help category. If helpcategory is None, default to CATEGORY_NONE.
        """
        fullname = h[cmd]
        details = cmdtable[fullname]
        helpcategory = details[0].helpcategory
        return helpcategory or help.registrar.command.CATEGORY_NONE

    cmdsbycategory = {category: [] for category in help.CATEGORY_ORDER}
    for cmd in cmds:
        # If a command category wasn't registered, the command won't get
        # rendered below, so we raise an AssertionError.
        if helpcategory(cmd) not in cmdsbycategory:
            raise AssertionError(
                "The following command did not register its (category) in "
                "help.CATEGORY_ORDER: %s (%s)" % (cmd, helpcategory(cmd))
            )
        cmdsbycategory[helpcategory(cmd)].append(cmd)

    # Print the help for each command. We present the commands grouped by
    # category, and we use help.CATEGORY_ORDER as a guide for a helpful order
    # in which to present the categories.
    for category in help.CATEGORY_ORDER:
        categorycmds = cmdsbycategory[category]
        if not categorycmds:
            # Skip empty categories
            continue
        # Print a section header for the category.
        # For now, the category header is at the same level as the headers for
        # the commands in the category; this is fixed in the next commit.
        ui.write(sectionfunc(help.CATEGORY_NAMES[category]))
        # Print each command in the category
        for f in sorted(categorycmds):
            if f.startswith(b"debug"):
                continue
            d = get_cmd(h[f], cmdtable)
            ui.write(subsectionfunc(d[b'cmd']))
            # short description
            ui.write(d[b'desc'][0])
            # synopsis
            ui.write(b"::\n\n")
            synopsislines = d[b'synopsis'].splitlines()
            for line in synopsislines:
                # some commands (such as rebase) have a multi-line
                # synopsis
                ui.write(b"   %s\n" % line)
            ui.write(b'\n')
            # description
            ui.write(b"%s\n\n" % d[b'desc'][1])
            # options
            opt_output = list(d[b'opts'])
            if opt_output:
                opts_len = max([len(line[0]) for line in opt_output])
                ui.write(_(b"Options:\n\n"))
                multioccur = False
                for optstr, desc in opt_output:
                    if desc:
                        s = b"%-*s  %s" % (opts_len, optstr, desc)
                    else:
                        s = optstr
                    ui.write(b"%s\n" % s)
                    if optstr.endswith(b"[+]>"):
                        multioccur = True
                if multioccur:
                    ui.write(
                        _(
                            b"\n[+] marked option can be specified"
                            b" multiple times\n"
                        )
                    )
                ui.write(b"\n")
            # aliases
            if d[b'aliases']:
                # Note the empty comment, this is required to separate this
                # (which should be a blockquote) from any preceding things (such
                # as a definition list).
                ui.write(
                    _(b"..\n\n    aliases: %s\n\n") % b" ".join(d[b'aliases'])
                )


def allextensionnames():
    return set(extensions.enabled().keys()) | set(extensions.disabled().keys())


if __name__ == "__main__":
    doc = b'hg.1.gendoc'
    if len(sys.argv) > 1:
        doc = encoding.strtolocal(sys.argv[1])

    ui = uimod.ui.load()
    # Trigger extensions to load. This is disabled by default because it uses
    # the current user's configuration, which is often not what is wanted.
    if encoding.environ.get(b'GENDOC_LOAD_CONFIGURED_EXTENSIONS', b'0') != b'0':
        extensions.loadall(ui)

    if doc == b'hg.1.gendoc':
        showdoc(ui)
    else:
        showtopic(ui, encoding.strtolocal(sys.argv[1]))