tests/test-duplicateoptions.py

util: extract compression code in `mercurial.utils.compression`

The code seems large enough to be worth extracting. This is similar to what was
done for various module in `mercurial/utils/`.

Since None of the compression logic takes a `ui` objet, issuing deprecation
warning is tricky. Luckly the logic does not seems to have many external users.

from __future__ import absolute_import, print_function
import os
from mercurial import (
    commands,
    extensions,
    ui as uimod,
)

ignore = {b'highlight', b'win32text', b'factotum', b'beautifygraph'}

try:
    import sqlite3
    del sqlite3 # unused, just checking that import works
except ImportError:
    ignore.add(b'sqlitestore')

if os.name != 'nt':
    ignore.add(b'win32mbcs')

disabled = [ext for ext in extensions.disabled().keys() if ext not in ignore]

hgrc = open(os.environ["HGRCPATH"], 'wb')
hgrc.write(b'[extensions]\n')

for ext in disabled:
    hgrc.write(ext + b'=\n')

hgrc.close()

u = uimod.ui.load()
extensions.loadall(u)
extensions.populateui(u)

globalshort = set()
globallong = set()
for option in commands.globalopts:
    option[0] and globalshort.add(option[0])
    option[1] and globallong.add(option[1])

for cmd, entry in commands.table.items():
    seenshort = globalshort.copy()
    seenlong = globallong.copy()
    for option in entry[1]:
        if ((option[0] and option[0] in seenshort) or
            (option[1] and option[1] in seenlong)):
            print("command '" + cmd + "' has duplicate option " + str(option))
        seenshort.add(option[0])
        seenlong.add(option[1])