hgext/fsmonitor/pywatchman/capabilities.py

copies: move short-circuiting of dirstate copies out of _forwardcopies()

I'd like to move the filtering of copies we do after chaining to the
end of all chaining (in a single place in pathcopies()). One problem
that came up when trying that was that we allow things like `hg cp -f
<file> <existing file>` so the user can later amend that in. Filtering
at the end would mean that we remove those copies. That would break
`hg st -C`. This patch therefore moves the short-circuiting of
dirstate copies into pathcopies() so we can more easily handle the
dirstate-only case differently.

I initially thought this might change some behavior when the user does
`hg status --rev 'wdir()' --rev .` during an uncommitted merge, since
_backwardrenames() would reverse the copies in that case. However, I
couldn't come up with a test case where it made a difference.

Differential Revision: https://phab.mercurial-scm.org/D6600

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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
# no unicode literals

import re

def parse_version(vstr):
    res = 0
    for n in vstr.split('.'):
        res = res * 1000
        res = res + int(n)
    return res

cap_versions = {
    "cmd-watch-del-all": "3.1.1",
    "cmd-watch-project": "3.1",
    "relative_root": "3.3",
    "term-dirname": "3.1",
    "term-idirname": "3.1",
    "wildmatch": "3.7",
}

def check(version, name):
    if name in cap_versions:
        return version >= parse_version(cap_versions[name])
    return False

def synthesize(vers, opts):
    """ Synthesize a capability enabled version response
        This is a very limited emulation for relatively recent feature sets
    """
    parsed_version = parse_version(vers['version'])
    vers['capabilities'] = {}
    for name in opts['optional']:
        vers['capabilities'][name] = check(parsed_version, name)
    for name in opts['required']:
        have = check(parsed_version, name)
        vers['capabilities'][name] = have
        if not have:
            vers['error'] = 'client required capability `' + name + \
                            '` is not supported by this server'
    return vers