contrib/hgclient.py

help: backout f3c4edfd35e1 (mark boolean flags with [no-] in help) for now

The ability to negate any boolean flags itself is great, but I think we are not
ready to expose the help side of it yet.

First, while there exist a handful of such flags whose default value can be
changed (eg: git diff, patchwork confirmation), there is only a few of them. The
users who benefit the most from this change are alias users and large
installation that can deploy extension to change behavior (eg: facebook
tweakdefault).  So the majority of user who will be affected by a large change
to command help that is not yet relevant to them. (I expect this to become
relevant when ui.progressive start to exists).

Below is an example of the impact of the new help on 'hg help diff':

  -r --rev REV [+]              revision
  -c --change REV               change made by revision
  -a --[no-]text                treat all files as text
  -g --[no-]git                 use git extended diff format
     --[no-]nodates             omit dates from diff headers
     --[no-]noprefix            omit a/ and b/ prefixes from filenames
  -p --[no-]show-function       show which function each change is in
     --[no-]reverse             produce a diff that undoes the changes
  -w --[no-]ignore-all-space    ignore white space when comparing lines
  -b --[no-]ignore-space-change ignore changes in the amount of white space
  -B --[no-]ignore-blank-lines  ignore changes whose lines are all blank
  -U --unified NUM              number of lines of context to show
     --[no-]stat                output diffstat-style summary of changes
     --root DIR                 produce diffs relative to subdirectory
  -I --include PATTERN [+]      include names matching the given patterns
  -X --exclude PATTERN [+]      exclude names matching the given patterns
  -S --[no-]subrepos            recurse into subrepositories

Another issue with the current state of help, the default value for the
flag is not conveyed to the user. For example in the 'backout' help, there is
no real distinction between "--[no-]backup" (default to True) and "--[no-]keep"
(default) to False:

  --[no-]backup        no backups
  --[no-]keep          do not modify working directory during strip

In addition, I've discussed with Augie Fackler and the last batch of the work on
this have burned him out quite some. Therefore he is not intending to perform
any more work on this topic. Quoting him, he would rather see the help part
backed out than spending more time on it.

I do not think we are ready to expose this to users in 4.0 (freeze in a week),
especially because we cannot expect quick improvement on these aspect as this
topic no longer have an owner. We should be able to reintroduce that change in
the future when someone get back on it and the main issues are solves:

* Introduction of  ui.progressive makes it relevant for a majority of user,
* Current default value are efficiently conveyed to the user.

(In addition, the excerpt from diff help show that we still have some issue with
some negative option like '--nodates' so further improvement are probably
welcome there.)

# A minimal client for Mercurial's command server

from __future__ import absolute_import, print_function
import os
import signal
import socket
import struct
import subprocess
import sys
import time

try:
    import cStringIO as io
    stringio = io.StringIO
except ImportError:
    import io
    stringio = io.StringIO

def connectpipe(path=None):
    cmdline = ['hg', 'serve', '--cmdserver', 'pipe']
    if path:
        cmdline += ['-R', path]

    server = subprocess.Popen(cmdline, stdin=subprocess.PIPE,
                              stdout=subprocess.PIPE)

    return server

class unixconnection(object):
    def __init__(self, sockpath):
        self.sock = sock = socket.socket(socket.AF_UNIX)
        sock.connect(sockpath)
        self.stdin = sock.makefile('wb')
        self.stdout = sock.makefile('rb')

    def wait(self):
        self.stdin.close()
        self.stdout.close()
        self.sock.close()

class unixserver(object):
    def __init__(self, sockpath, logpath=None, repopath=None):
        self.sockpath = sockpath
        cmdline = ['hg', 'serve', '--cmdserver', 'unix', '-a', sockpath]
        if repopath:
            cmdline += ['-R', repopath]
        if logpath:
            stdout = open(logpath, 'a')
            stderr = subprocess.STDOUT
        else:
            stdout = stderr = None
        self.server = subprocess.Popen(cmdline, stdout=stdout, stderr=stderr)
        # wait for listen()
        while self.server.poll() is None:
            if os.path.exists(sockpath):
                break
            time.sleep(0.1)

    def connect(self):
        return unixconnection(self.sockpath)

    def shutdown(self):
        os.kill(self.server.pid, signal.SIGTERM)
        self.server.wait()

def writeblock(server, data):
    server.stdin.write(struct.pack('>I', len(data)))
    server.stdin.write(data)
    server.stdin.flush()

def readchannel(server):
    data = server.stdout.read(5)
    if not data:
        raise EOFError
    channel, length = struct.unpack('>cI', data)
    if channel in 'IL':
        return channel, length
    else:
        return channel, server.stdout.read(length)

def sep(text):
    return text.replace('\\', '/')

def runcommand(server, args, output=sys.stdout, error=sys.stderr, input=None,
               outfilter=lambda x: x):
    print('*** runcommand', ' '.join(args))
    sys.stdout.flush()
    server.stdin.write('runcommand\n')
    writeblock(server, '\0'.join(args))

    if not input:
        input = stringio()

    while True:
        ch, data = readchannel(server)
        if ch == 'o':
            output.write(outfilter(data))
            output.flush()
        elif ch == 'e':
            error.write(data)
            error.flush()
        elif ch == 'I':
            writeblock(server, input.read(data))
        elif ch == 'L':
            writeblock(server, input.readline(data))
        elif ch == 'r':
            ret, = struct.unpack('>i', data)
            if ret != 0:
                print(' [%d]' % ret)
            return ret
        else:
            print("unexpected channel %c: %r" % (ch, data))
            if ch.isupper():
                return

def check(func, connect=connectpipe):
    sys.stdout.flush()
    server = connect()
    try:
        return func(server)
    finally:
        server.stdin.close()
        server.wait()